As part of the global effort to mitigate climate change effects, New Zealand’s Climate Change Commission has recommended the establishment of 300,000 ha of native trees across the country by 2035. To achieve this goa...As part of the global effort to mitigate climate change effects, New Zealand’s Climate Change Commission has recommended the establishment of 300,000 ha of native trees across the country by 2035. To achieve this goal, significant improvement in seedling production and field establishment is needed. Across New Zealand, there is a trade-off between seedling size and early seedling establishment success;plants grown in large pots are more resistant to weeds, pests and frost;however, they are more expensive and take longer to grow. We tested this trade-off between cost and establishment success by raising seedlings of twelve key native species in three container grade sizes: small, large, and revegetation grade, and tracking their success across five sites around Rotorua, in the Central North Island of New Zealand. After two-year post-planting, we found that high-quality sites and larger container systems tended to promote higher survival and faster early growth (plant height and root collar diameter). Some species, such as Kunzea ericoides and Leptospermum scoparium, survived and grew well (> 75%) even when raised in small container sizes. Other species such as Sophora microphylla had very low survival (< 25%) even when raised in revegetation container grade sizes. If the quality of the planting site is high, the container size seems to be less important for most species. Other species such as Aristotelia serrata, Cordyline australis, Plagianthus regius and Podocarpus totara appear to depend more on site quality. In conclusion, nursery container systems for raising New Zealand native plants should be chosen based on the biology of the species, nursery management practices, quality of the planting site, and a balance between cost and benefit for each situation.展开更多
Short rotation plantation forestry(SRF)is being widely adopted to increase wood production,in order to meet global demand for wood products.However,to ensure maximum gains from SRF,optimised management regimes need to...Short rotation plantation forestry(SRF)is being widely adopted to increase wood production,in order to meet global demand for wood products.However,to ensure maximum gains from SRF,optimised management regimes need to be established by integrating robust predictions and an understanding of mechanisms underlying tree growth.Hybrid ecophysiological models,such as potentially useable light sum equation(PULSE)models,are useful tools requiring minimal input data that meet the requirements of SRF.PULSE models have been tested and calibrated for different evergreen conifers and broadleaves at both juvenile and mature stages of tree growth with coarse soil and climate data.Therefore,it is prudent to question:can adding detailed soil and climatic data reduce errors in this type of model?In addition,PULSE techniques have not been used to model deciduous species,which are a challenge for ecophysiological models due to their phenology.This study developed a PULSE model for a clonal Populus tomentosa plantation in northern China using detailed edaphic and climatic data.The results showed high precision and low bias in height(m)and basal area(m^(2)·ha^(-1))predictions.While detailed edaphoclimatic data produce highly precise predictions and a good mechanistic understanding,the study suggested that local climatic data could also be employed.The study showed that PULSE modelling in combination with coarse level of edaphic and local climate data resulted in reasonably precise tree growth prediction and minimal bias.展开更多
Investing in projects that support environmental benefits,such as tree harvesting,has the potential to reduce air pollution levels in the atmosphere in the future.However,this kind of investment may increase the curre...Investing in projects that support environmental benefits,such as tree harvesting,has the potential to reduce air pollution levels in the atmosphere in the future.However,this kind of investment may increase the current level of emissions.Therefore,it is necessary to estimate how much the policy affects the current level of CO_(2) emissions.This makes sure the policy doesn’t increase the level of CO_(2) emis-sions.This study aims to analyze the effect of the One Bil-lion Trees program on CO_(2) emissions in New Zealand by employing the 2020 input–output table analysis.This inves-tigation examines the direct and indirect effects of policy on both the demand and supply sides across six regions of New Zealand.The results of this study for the first year of plantation suggest that the policy increases the level of CO_(2) emissions in all regions,especially in the Waikato region.The direct and indirect impact of the policy leads to 64 kt of CO_(2) emissions on the demand side and 270 kt of CO_(2) emis-sions on the supply side.These lead to 0.19 and 0.74%of total CO_(2) emissions being attributed to investment shocks.Continuing the policy is recommended,as it has a low effect on CO_(2) emissions.However,it is crucial to prioritize the use of low-carbon machinery that uses fossil fuels during the plantation process.展开更多
Dear Editor,Remediation of cadmium(Cd)-contaminated soil is a popular topic in global environmental science.Phytoremediation using hyperaccumulators or certain plants to accumulate and remove Cd from polluted soils is...Dear Editor,Remediation of cadmium(Cd)-contaminated soil is a popular topic in global environmental science.Phytoremediation using hyperaccumulators or certain plants to accumulate and remove Cd from polluted soils is a promising approach.Wei et al.(2005)first described Solanum nigrum L.as a Cd hyperaccumulator.Subsequently,various aspects of S.nigrum,including the protective effects on proline,physiological and biochemical responses,earthworms,arbuscular mycorrhizal fungi,and fertilizers and the intercropping with Solanum photeinocarpum,have been extensively studied(Xu et al.,2009;Khan et al.,2014;Wang et al.,2015;Tang et al.,2017;Yang et al.,2019).展开更多
The canola oil industry generates significant waste as canola meal(CM)which has limited scope and applications.This study demonstrates the possibility of valorization of CM as a sustainable natural filler in a biodegr...The canola oil industry generates significant waste as canola meal(CM)which has limited scope and applications.This study demonstrates the possibility of valorization of CM as a sustainable natural filler in a biodegradable polymer composite of Poly(lactic acid)(PLA).Generally,interfacial bonding between natural fibers and the polymer matrix in the composite is weak and non-uniform.One possible solution is to derivatize natural fibre to introduce interfacial bond strength and compatibility with the PLA polymer matrix.Here,CM was succinylated in a reactive extrusion process using succinic anhydride at 30 wt%to get 14%derivatization with 0.02 g of-COOH density per g of CM.The CM or succinylated CM at 5 and 15 wt%was co-extruded with amorphous PLA to get composite fibers.CM-PLA and succinylated CM-PLA biocomposites were foamed using a mild and green microcellular foaming process,with CO_(2) as an impregnating agent without any addition of organic solvents.The properties of the foams were analyzed using differential scanning calorimetry(DSC),Dynamic mechanical thermal analysis(DMTA),shrinkage,and imaging.The addition of CM or succinylated CM as a natural filler did not significantly change the glass transition temperature,melting point,percent crystallization,stiffness,and thermal stability of PLA foams.This suggests succinylation(modification)of CM is not a mandatory step for improving interphase compatibility with the amorphous PLA.The new PLA-CM foams can be a good alternative in the packaging industry replacing the existing petroleum-based polymer foams.展开更多
Background:Natural forests cover approximately 29%of New Zealand’s landmass and represent a large terrestrial carbon pool.In 2002 New Zealand implemented its first representative plot-based natural forest inventory t...Background:Natural forests cover approximately 29%of New Zealand’s landmass and represent a large terrestrial carbon pool.In 2002 New Zealand implemented its first representative plot-based natural forest inventory to assess carbon stocks and stock changes in these mostly undisturbed old-growth forests.Although previous studies have provided estimates of biomass or carbon stocks,these were either not fully representative or lacked data from important pools such as dead wood(coarse woody debris).The current analysis provides the most complete estimates of carbon stocks and stock changes in natural forests in New Zealand.Results:We present estimates of per hectare carbon stocks and stock changes in live and dead organic matter pools excluding soil carbon based on the first two measurement cycles of the New Zealand Natural Forest Inventory carried out from 2002 to 2014.These show that New Zealand’s natural forests are in balance and are neither a carbon source nor a carbon sink.The average total carbon stock was 227.0±14.4 tC·ha^(−1)(95%C.I.)and did not change significantly in the 7.7 years between measurements with the net annual change estimated to be 0.03±0.18 tC·ha^(−1)·yr^(−1).There was a wide variation in carbon stocks between forest groups.Regenerating forest had an averaged carbon stock of only 53.6±9.4 tC·ha^(−1) but had a significant sequestration rate of 0.63±0.25 tC·ha^(−1)·yr^(−1),while tall forest had an average carbon stock of 252.4±15.5 tC·ha^(−1),but its sequestration rate did not differ significantly from zero(−0.06±0.20 tC·ha^(−1)·yr^(−1)).The forest alliance with the largest average carbon stock in above and below ground live and dead organic matter pools was silver beech-red beech-kamahi forest carrying 360.5±34.6 tC·ha^(−1).Dead wood and litter comprised 27%of the total carbon stock.Conclusions:New Zealand’s Natural Forest Inventory provides estimates of carbon stocks including estimates for difficult to measure pools such as dead wood and roots.It also provides estimates of uncertainties including effects of model prediction error and sampling variation between plots.Importantly it shows that on a national level New Zealand’s natural forests are in balance.Nevertheless,this is a nationally important carbon pool that requires continuous monitoring to identify potential negative or positive changes.展开更多
Organic pollutants, such as polychlorinated dJbenzo-p-dioxins and polychlofinated dibenzofurans （PCDD/Fs）, polychlodnated biphenyls （PCBs）, antibiotics, herbicides, and bisphenol A （BPA）, are commonly found in a...Organic pollutants, such as polychlorinated dJbenzo-p-dioxins and polychlofinated dibenzofurans （PCDD/Fs）, polychlodnated biphenyls （PCBs）, antibiotics, herbicides, and bisphenol A （BPA）, are commonly found in agricultural environments. They are released into the environment as a result of their use for human health purposes and farm management activities, and are often discharged as waste-water effluents. Most of these organic pollutants are taken up by plants through roots and leaves, and when they enter the tissue, they cause serious damage to the plants. Although the toxicity of organic pollutants to plants, especially to plant cells, has been intensively studied, a systematic review of these studies is lacking. Here we review researches on the toxicity of organic pollutants, their uptake, and translocation in plants. Our objective is to assemble existing knowledge concerning the interaction of organic pollutants with plants, which should be useful for the development of plant-based systems for removing pollutants from aquatic and agricultural environments.展开更多
Objective To identify the bamboo VOCs (volatile organic compounds) effect on animal physiological indices, which associated with human health. Methods GC/MS was used to analyze the volatile organic compounds from Mos...Objective To identify the bamboo VOCs (volatile organic compounds) effect on animal physiological indices, which associated with human health. Methods GC/MS was used to analyze the volatile organic compounds from Moso bamboo (Phyllostachys heterocyla cv. pubescens). The effect of VOCs on environmental health was evaluated by analyzing the metabolic indices of the type 2 diabetic mouse model. Results Spectra of VOC generated by GC/MS were blasted against an in-house MS library confirming the identification of 33 major components that were manually validated. The relative constituent compounds as a percentage of total VOCs determined were alcohols (34.63%), followed by ether (22.02%), aldehyde (15.84%), ketone (11.47%), ester (4.98%), terpenoid (4.38%), and acids (3.83%). Further experimentation established that the metabolic incidence of the disease can be improved if treated with vanillin, leaf alcohol,β-ionone and methyl salicylate. The effects of these VOCs on type 2 diabetes were evident in the blood lipid and blood glucose levels. Conclusion Our model suggests that VOCs can potentially control the metabolic indices in type 2 diabetes mice. This experiment data also provides the scientific basis for the comprehensive utilization of ornamental bamboos and some reference for other similar study of environmental plants.展开更多
Disparities in the substrate affinity and tolerance threshold for ammonia have been believed to play a key role in driving niche differentiation between ammonia-oxidizing archaea (AOA) and bacteria (AOB);however, rece...Disparities in the substrate affinity and tolerance threshold for ammonia have been believed to play a key role in driving niche differentiation between ammonia-oxidizing archaea (AOA) and bacteria (AOB);however, recent surveys argue that direct competition between AOA and AOB is also important in this phenomenon. Accordingly, it is reasonable to predict that diverse AOA lineages would grow in ammonium (NH_(4)^(+))-rich alkaline arable soils if AOB growth is suppressed. To test this hypothesis, a microcosm study was established using three different types of alkaline arable soils, in which a high NH_(4)^(+) concentration (200 μg N g^(-1) dry soil) was maintained by routinely replenishing urea and the activities of AOB were selectively inhibited by 1-octyne or 3,4-dimethylpyrazole phosphate (DMPP). Compared with amendment with urea alone, 1-octyne partially retarded AOB growth, while DMPP completely inhibited AOB. Both inhibitors accelerated the growth of AOA, with significantly higher ratios of abundance of AOA to AOB observed with DMPP amendment across soils. Nonmetric multidimensional scaling analysis (NMDS) indicated that different treatments significantly altered the community structures of both AOA and AOB and AOA OTUs enriched by high-NH_(4)^(+) amendment were taxonomically constrained across the soils tested and closely related to Nitrososphaera viennensis EN76 and N. garnensis. Given that these representative strains have been demonstrated to be sensitive to high ammonia concentrations, our results suggest that it is the competitiveness for ammonia, rather than disparities in substrate affinity and tolerance threshold for ammonia, that drives niche differentiation between these phylotypes and AOB in NH_(4)^(+)-rich alkaline soils.展开更多
A hydroponic experiment was carried out to study the effect of elevated carbon dioxide(CO2) on root growth of tomato seedlings.Compared with the control(350 μL L-1),CO2 enrichment(800 μL L-1) significantly increased...A hydroponic experiment was carried out to study the effect of elevated carbon dioxide(CO2) on root growth of tomato seedlings.Compared with the control(350 μL L-1),CO2 enrichment(800 μL L-1) significantly increased the dry matter of both shoot and root,the ratio of root to shoot,total root length,root surface area,root diameter,root volume,and root tip numbers,which are important for forming a strong root system.The elevated CO2 treatment also significantly improved root hair development and elongation,thus enhancing nutrient uptake.Increased indole acetic acid concentration in plant tissues and ethylene release in the elevated CO2 treatment might have resulted in root growth enhancement and root hair development and elongation.展开更多
Mixed or chloride salty ions dominate in saline soils, and exert wide-ranging adversely affect on soil biological processes and soil functions. The objectives of this study were to（1） explore the impacts of mixed（0...Mixed or chloride salty ions dominate in saline soils, and exert wide-ranging adversely affect on soil biological processes and soil functions. The objectives of this study were to（1） explore the impacts of mixed（0, 3, 6, 10, 20 and 40 g Cl–/SO42–salt/kg dry soil） and chloride（0, 1.5, 3, 5, 8 and 15 g Cl– salt/kg dry soil） salts on soil enzyme activities, soil physiological functional（Biolog） profiles and microbial community structure by using soil enzymatic, Biolog-Eco microplates as well as denaturing gradient gel electrophoresis（DEEG） methods, and（2） determine the threshold concentration of soil electronic conductivity（EC1：5） on maintaining the functional and structural diversity of soil microbial community. The addition of either Cl– or mixed Cl–/SO42–salt obviously increased soil EC, but adversely affected soil biological activities including soil invertase activity, soil microbial biomass carbon（MBC） and substrate-induced respiration（SIR）. Cl– salt showed a greater deleterious influence than mixed Cl–/SO42–salt on soil enzymes and MBC, e.g., the higher soil MBC consistently appeared with Cl–/SO42–instead of Cl– treated soil. Meanwhile, we found that SIR was more reliable than soil basal respiration（SBR） on explaining the changes of soil biological activity responsive to salt disturbance. In addition, microbial community structures of the soil bacteria, fungi, and Bacillus were obviously affected by both salt types and soil EC levels, and its diversity increased with increasing of mixed Cl–/SO42–salt rates, and then sharply declined down after it reached critical point. Moreover, the diversity of fungal community was more sensitive to the mixed salt addition than other groups. The response of soil physiological profiles（Biolog） followed a dose-response pattern with Cl–（R2=0.83） or mixed Cl–/SO42–（R2=0.89） salt. The critical threshold concentrations of salts for soil physiological function were 0.45 d S/m for Cl– and 1.26 d S/m for Cl–/SO42–, and those for soil microbial community structural diversity were 0.70 d S/m for Cl– and 1.75 d S/m for Cl–/SO42–.展开更多
Oxytetracycline(OTC)residues have been found in soil and water,and they may pose potential risks to agricultural ecological environments.One of the most impactful ways for OTC to enter the soil and water environments ...Oxytetracycline(OTC)residues have been found in soil and water,and they may pose potential risks to agricultural ecological environments.One of the most impactful ways for OTC to enter the soil and water environments is through excrement used as organic fertilizer.Therefore,it is important to remove OTC during manure composting and to understand the transformation of the organic materials during composting in the presence of OTC.In the present paper,chicken manure and wheat sawdust spiked with OTC were composted under different initial moisture contents(MC)to evaluate the degradation of OTC and changes of organic matter during the composting process.The MC has a significant effect on OTC degradation during composting.A higher MC of 65% was more conducive to OTC degradation(77.4%)and compost maturity compared to the lower MC.However,the higher MC of 65%could increase the ammonia volatilization by promoting nitrification compared to the lower MC.An increase in the initial MC could improve the composting temperature.NMR results illustrated that the presence of OTC could affect the internal transformation of aliphatics,and OTC inhibited compost humification.Thus,an initial MC of 55–65% can alleviate the impacts of OTC on humification during manure composting.展开更多
In this study the transfer characteristics of mercury(Hg)from a wide range of Chinese soils to corn grain(cultivar Zhengdan 958)were investigated.Prediction models were developed for determining the Hg bioconcentratio...In this study the transfer characteristics of mercury(Hg)from a wide range of Chinese soils to corn grain(cultivar Zhengdan 958)were investigated.Prediction models were developed for determining the Hg bioconcentration factor(BCF)of Zhengdan 958 from soil,including the soil properties,such as p H,organic matter(OM)concentration,cation exchange capacity(CEC),total nitrogen concentration(TN),total phosphorus concentration(TP),total potassium concentration(TK),and total Hg concentration(THg),using multiple stepwise regression analysis.These prediction models were applied to other non-model corn cultivars using a cross-species extrapolation approach.The results indicated that the soil p H was the most important factor associated with the transfer of Hg from soil to corn grain.Hg bioaccumulation in corn grain increased with the decreasing p H.No significant differences were found between two prediction models derived from different rates of Hg applied to the soil as HgCl2.The prediction models established in this study can be applied to other non-model corn cultivars and are useful for predicting Hg bioconcentration in corn grain and assessing the ecological risk of Hg in different soils.展开更多
Background:The grazing behaviour of herbivores and their grazing personalities might in part be determined genetically,but there are few studies in beef cattle illustrating this.In this study,we investigated for first...Background:The grazing behaviour of herbivores and their grazing personalities might in part be determined genetically,but there are few studies in beef cattle illustrating this.In this study,we investigated for first time the genetic variation within a candidate‘grazing gene',the glutamate metabotropic receptor 5 gene(GRM5),and tested associations between variation in that gene and variation in grazing personality behaviours(GP-behaviours)displayed by free-ranging cows during winter grazing in the steep and rugged rangelands of New Zealand.Mature beef cows(n=303,from 3 to 10 years of age)were tracked with global positioning system(GPS)and,with 5-minutes(min)relocation frequency,various GP-behaviours were calculated.These included horizontal and vertical distances travelled,mean elevation,elevation range,elevation gain,slope,home range and movement tortuosity,variously calculated using daily relocation trajectories with repeated measurements(i.e.,7 to 24 days(d))and satellite-derived digital elevation models(DEM).The different GP-behaviours were fitted into mixed models to ascertain their associations with variant sequences and genotypes of GRM5.Results:We discovered three GRM5 variants(A,B and C)and identified the six possible genotypes in the cattle studied.The mixed models revealed that A was significantly associated with elevation range,home range and movement tortuosity.Similarly,GRM5 genotypes were associated(P<0.05)to home range and movement tortuosity,while trends suggesting association(P<0.1)were also revealed for elevation range and horizontal distance travelled.Most GP-behaviour models were improved by correcting for cow age-class as a fixed factor.The analysis of GP-behaviours averaged per cow age-class suggests that grazing personality is fully established as beef cows reached 4 years of age.Home range and movement tortuosity were not only associated with GRM5 variation,but also negatively correlated with each other(r=-0.27,P<0.001).Conclusions:There seems to be a genetically determined trade-off between home range and movement tortuosity that may be useful in beef cattle breeding programmes aiming to improve the grazing distribution and utilisation of steep and rugged rangelands.展开更多
Exogenous application of a cytokinin-like compound forchlorfenuron(CPPU)can promote fruit growth,although often at the expense of dry matter(DM),an important indicator of fruit quality.Actinidia chinensis var.delicios...Exogenous application of a cytokinin-like compound forchlorfenuron(CPPU)can promote fruit growth,although often at the expense of dry matter(DM),an important indicator of fruit quality.Actinidia chinensis var.deliciosa‘Hayward’fruit are very responsive to CPPU treatments,but the mechanism underlying the significant fruit weight increase and associated decrease in DM is unclear.In this study,we hypothesised that CPPU-enhanced growth increases fruit carbohydrate demand,but limited carbohydrate supply resulted in decreased fruit DM.During fruit development,CPPU effects on physical parameters,metabolites,osmotic pressure and transcriptional changes were assessed under conditions of both standard and a high carbohydrate supply.We showed that CPPU increased fruit fresh weight but the dramatic DM decrease was not carbohydrate limited.Enhanced glucose and fructose concentrations contributed to an increase in soluble carbohydrate osmotic pressure,which was correlated with increased water accumulation in CPPU-treated fruit and up-regulation of water channel aquaporin gene PIP2.4 at 49 days after anthesis.Transcipt analysis suggested that the molecular mechanism contributing to increased glucose and fructose concentrations was altered by carbohydrate supply.At standard carbohydrate supply,the early glucose increase in CPPU fruit was associated with reduced starch synthesis and increased starch degradation.When carbohydrate supply was high,the early glucose increase in CPPU fruit was associated with a general decrease in starch synthesis but up-regulation of vacuolar invertase and fructokinase genes.We conclude that CPPU affected fruit expansion by increasing the osmotically-driven water uptake and its effect was not carbohydrate supply-limited.展开更多
Background:Forest management practices(e.g.choice of stand density,fertilisation)are just as important in carbon(C)forestry as in other types of forestry and will affect the level of C sequestration and profitability....Background:Forest management practices(e.g.choice of stand density,fertilisation)are just as important in carbon(C)forestry as in other types of forestry and will affect the level of C sequestration and profitability.Because C stored in wood is approximately proportional to the product of its volume and density,it is necessary to account for both volume growth and wood density when assessing the effects of fertilisation on C sequestration in pine forests.Methods:The effects of nitrogen(N)input from biosolids application on forest C sequestration were quantified from an intensively monitored biosolids field trial in a Pinus radiata plantation on a sandy soil in New Zealand.The field trial tested the application of three biosolids rates:Control(no application),Standard(300 kg N⋅ha^(-1) applied every three years),and High(600 kg N⋅ha^(-1) applied every three years),across three levels of stand density:300,450,and 600 stems⋅ha^(-1).Carbon sequestration was estimated using the C-Change model from annual plot measurements of stand density,stem height and diameter,and annual breast height wood densities obtained from increment cores.Results:By age 24 years,N-fertilised trees had sequestered 40 t C⋅ha^(-1) more than unfertilised trees,an increase of 18%.Fertilisation increased stem volume by 23%but reduced stem wood density by 2.5%.Most of the increased C sequestration occurred between age 6 and age 17 years and the Standard rate gave the same increase in C sequestration as the High rate.On average,there was no significant difference in growth rate between fertilised and unfertilised trees after the 17th growth year,but the increased growth ceased earlier at higher stand densities,and later at lower stand densities.Conclusions:This study indicates that 2–3 applications of the Standard rate would have been sufficient to achieve the increased C sequestration,with an applied N to C conversion ratio of 43–65 kg C⋅kg^(-1) N.Our results highlight that N fertilisation will become more widespread under greenhouse gas emissions trading schemes which en-courages forest management practices that improve C sequestration in young forests in New Zealand in particular and other countries in general.展开更多
Chitosan oligomers （average Dp-4） are known for their antifungal activity and wood decay resistance. These oligomers are susceptible to moisture, and promote yeast growth upon air exposure after a sufficient length ...Chitosan oligomers （average Dp-4） are known for their antifungal activity and wood decay resistance. These oligomers are susceptible to moisture, and promote yeast growth upon air exposure after a sufficient length of time. Chitosan oligomers of three different states viz. completely dried, freshly prepared and highly viscous form, were prepared to compare their in-vitro antifungal activities against three brown-rot fungi, two sapstain and one mould fungus using agar nutrient medium. Additionally, a mixture of chitosan oligomers and boric acid was used for wood treatment. The nutrient medium bioassay results show that all states of chitosan oligomers inhibited the growth of tested basidiomycetes fungi, but not sapstain and mould fungi. Subsequently, wood decay results confirm antifungal activity of chitosan oligomers plus boron against basidiomycetes, but highlighted their leachability upon water exposure.展开更多
A competitive co-evolutionary Multi-Objective Genetic Algorithm (cc-MOGA) was used to approximate a Pareto front of efficient silvicultural regimes for Eucalyptus fastigata. The three objectives to be maximised includ...A competitive co-evolutionary Multi-Objective Genetic Algorithm (cc-MOGA) was used to approximate a Pareto front of efficient silvicultural regimes for Eucalyptus fastigata. The three objectives to be maximised included, sawlog, pulpwood and carbon sequestration payment. Three carbon price scenarios (3CPS), i.e. NZ $25, NZ $50 and NZ $100 for a tonne of CO2 sequestered, were used to assess the impact on silvicultural regimes, against a fourth non-carbon Pareto set of efficient regimes (nonCPS), determined from a cc-MOGA with two objectives, i.e. competing sawlog and pulpwood productions. Carbon prices included in stand valuation were found to influence the silvicultural regimes by increasing the rotation length and lowering the final crop number before clearfell. However, there were no significant changes in the frequency, timing, and intensity of thinning operations amongst all the four Pareto sets of solutions. However, the 3CPS were not significantly different from each other, which meant that these silvicultural regimes were insensitive to the price of carbon. This was because maximising carbon sequestration was directly related to the biological growth rate. As such an optimal mix of frequency, intensity, and timing of thinning maintained maximum growth rate for as long as possible for any one rotation.展开更多
Restoration of grassland such as exclusion of grazing has been considered to increase aboveground plant diversity and soil fertility. However, knowledge on the effect of long-term exclusion of grazing on soil bacteria...Restoration of grassland such as exclusion of grazing has been considered to increase aboveground plant diversity and soil fertility. However, knowledge on the effect of long-term exclusion of grazing on soil bacterial community structure and diversity is not well understood. The two sites were selected in the Inner Mongolian grassland, i.e., one fenced off since 1979 (UG79) and the other continually grazed by sheep (FG) all along. Soil microbial biomass was measured using fumigation method and bacterial community structure and diversity were assessed using methods of Denaturing Gradient Gel Electrophoresis (DGGE) and clone library. Results showed that the UG79 soil had significantly higher microbial biomass carbon and nitrogen compared with the FG soil. There was a clear separation in soil bacterial community structure, but not in bacterial diversity between the two sites. Moreover, 55 clones from the UG79 soil and 56 clones from the FG soil were selected and sequenced. Phylogenetic analysis of all clone sequences indicated that bacterial communities were dominated by the groups of Actinomycetes, Proteobacteria and Bacteroidetes, but there were no significant differences in bacterial diversity between the two sites, consistent with the results obtained from DGGE. The results highlighted that although long-term exclusion of grazing increased soil microbial biomass, but it did not harbor higher bacterial diversity compared with freely grazed site.展开更多
基金supported by Te Uru Rākau,Ministry of Primary Industry-1 Billion trees project(QT-8094 TUR_2020_026 MPI)Scion SSIF funding(0810–P15502).
文摘As part of the global effort to mitigate climate change effects, New Zealand’s Climate Change Commission has recommended the establishment of 300,000 ha of native trees across the country by 2035. To achieve this goal, significant improvement in seedling production and field establishment is needed. Across New Zealand, there is a trade-off between seedling size and early seedling establishment success;plants grown in large pots are more resistant to weeds, pests and frost;however, they are more expensive and take longer to grow. We tested this trade-off between cost and establishment success by raising seedlings of twelve key native species in three container grade sizes: small, large, and revegetation grade, and tracking their success across five sites around Rotorua, in the Central North Island of New Zealand. After two-year post-planting, we found that high-quality sites and larger container systems tended to promote higher survival and faster early growth (plant height and root collar diameter). Some species, such as Kunzea ericoides and Leptospermum scoparium, survived and grew well (> 75%) even when raised in small container sizes. Other species such as Sophora microphylla had very low survival (< 25%) even when raised in revegetation container grade sizes. If the quality of the planting site is high, the container size seems to be less important for most species. Other species such as Aristotelia serrata, Cordyline australis, Plagianthus regius and Podocarpus totara appear to depend more on site quality. In conclusion, nursery container systems for raising New Zealand native plants should be chosen based on the biology of the species, nursery management practices, quality of the planting site, and a balance between cost and benefit for each situation.
基金The National Key Research and Development Program of China(Grant No.2021YFD2201203)the 5·5 Engineering Research&Innovation Team Project of Beijing Forestry University(No.BLRC2023C05)the Key Research and Development Program of Shandong Province(No.2021SFGC02050102)。
文摘Short rotation plantation forestry(SRF)is being widely adopted to increase wood production,in order to meet global demand for wood products.However,to ensure maximum gains from SRF,optimised management regimes need to be established by integrating robust predictions and an understanding of mechanisms underlying tree growth.Hybrid ecophysiological models,such as potentially useable light sum equation(PULSE)models,are useful tools requiring minimal input data that meet the requirements of SRF.PULSE models have been tested and calibrated for different evergreen conifers and broadleaves at both juvenile and mature stages of tree growth with coarse soil and climate data.Therefore,it is prudent to question:can adding detailed soil and climatic data reduce errors in this type of model?In addition,PULSE techniques have not been used to model deciduous species,which are a challenge for ecophysiological models due to their phenology.This study developed a PULSE model for a clonal Populus tomentosa plantation in northern China using detailed edaphic and climatic data.The results showed high precision and low bias in height(m)and basal area(m^(2)·ha^(-1))predictions.While detailed edaphoclimatic data produce highly precise predictions and a good mechanistic understanding,the study suggested that local climatic data could also be employed.The study showed that PULSE modelling in combination with coarse level of edaphic and local climate data resulted in reasonably precise tree growth prediction and minimal bias.
基金Open Access funding enabled and organized by CAUL and its Member Institutions
文摘Investing in projects that support environmental benefits,such as tree harvesting,has the potential to reduce air pollution levels in the atmosphere in the future.However,this kind of investment may increase the current level of emissions.Therefore,it is necessary to estimate how much the policy affects the current level of CO_(2) emissions.This makes sure the policy doesn’t increase the level of CO_(2) emis-sions.This study aims to analyze the effect of the One Bil-lion Trees program on CO_(2) emissions in New Zealand by employing the 2020 input–output table analysis.This inves-tigation examines the direct and indirect effects of policy on both the demand and supply sides across six regions of New Zealand.The results of this study for the first year of plantation suggest that the policy increases the level of CO_(2) emissions in all regions,especially in the Waikato region.The direct and indirect impact of the policy leads to 64 kt of CO_(2) emissions on the demand side and 270 kt of CO_(2) emis-sions on the supply side.These lead to 0.19 and 0.74%of total CO_(2) emissions being attributed to investment shocks.Continuing the policy is recommended,as it has a low effect on CO_(2) emissions.However,it is crucial to prioritize the use of low-carbon machinery that uses fossil fuels during the plantation process.
基金supported by Sanqin Talents,Shaanxi Provincial First-class Team——“Contaminated Soil Remediation and Resource Utilization Innovation Team at Shaanxi University of Technology”,China,Shaanxi University of Technology Research Ability Enhancement Project,China(No.SLGNL202405)Qin Chuangyuan“Scientists+Engineers”Team Construction in Shaanxi Province,China(No.2024QCY-KXJ-104)+5 种基金the Open Fund of Cultivation State Key Laboratory of Qinba Biological Resources and Ecological Environment,China(No.SLGPT2019KF0402)Qinba Bioremediation and Resource Development Research and Innovation Base,China(No.2022-ZC-GXYZ0029)the Project of Foreign Experts Bureau of Shaanxi Province,China(No.2024WZ-ZDXM-15)the Project of Foreign Experts Bureau of China(Nos.G2023041029L and DL2023041006L)the City University Co-construction of Shaanxi Province,China(No.SXJ-2101)the program financed by Poland Minister of Science under the“Regional Excellence Initiative”for 2024–2027。
文摘Dear Editor,Remediation of cadmium(Cd)-contaminated soil is a popular topic in global environmental science.Phytoremediation using hyperaccumulators or certain plants to accumulate and remove Cd from polluted soils is a promising approach.Wei et al.(2005)first described Solanum nigrum L.as a Cd hyperaccumulator.Subsequently,various aspects of S.nigrum,including the protective effects on proline,physiological and biochemical responses,earthworms,arbuscular mycorrhizal fungi,and fertilizers and the intercropping with Solanum photeinocarpum,have been extensively studied(Xu et al.,2009;Khan et al.,2014;Wang et al.,2015;Tang et al.,2017;Yang et al.,2019).
基金supported by the Biopolymer Network Limited(a research collaboration funded by the New Zealand Ministry of Business,Innovation and Employment).
文摘The canola oil industry generates significant waste as canola meal(CM)which has limited scope and applications.This study demonstrates the possibility of valorization of CM as a sustainable natural filler in a biodegradable polymer composite of Poly(lactic acid)(PLA).Generally,interfacial bonding between natural fibers and the polymer matrix in the composite is weak and non-uniform.One possible solution is to derivatize natural fibre to introduce interfacial bond strength and compatibility with the PLA polymer matrix.Here,CM was succinylated in a reactive extrusion process using succinic anhydride at 30 wt%to get 14%derivatization with 0.02 g of-COOH density per g of CM.The CM or succinylated CM at 5 and 15 wt%was co-extruded with amorphous PLA to get composite fibers.CM-PLA and succinylated CM-PLA biocomposites were foamed using a mild and green microcellular foaming process,with CO_(2) as an impregnating agent without any addition of organic solvents.The properties of the foams were analyzed using differential scanning calorimetry(DSC),Dynamic mechanical thermal analysis(DMTA),shrinkage,and imaging.The addition of CM or succinylated CM as a natural filler did not significantly change the glass transition temperature,melting point,percent crystallization,stiffness,and thermal stability of PLA foams.This suggests succinylation(modification)of CM is not a mandatory step for improving interphase compatibility with the amorphous PLA.The new PLA-CM foams can be a good alternative in the packaging industry replacing the existing petroleum-based polymer foams.
基金The New Zealand Ministry for the Environment provided funding to undertake data analysis and preparation of this manuscript under Statement of Work 21078Additional support was provided by the New Zealand Ministry for Business,Innovation and Employment Core funding to Crown Research Institutes.
文摘Background:Natural forests cover approximately 29%of New Zealand’s landmass and represent a large terrestrial carbon pool.In 2002 New Zealand implemented its first representative plot-based natural forest inventory to assess carbon stocks and stock changes in these mostly undisturbed old-growth forests.Although previous studies have provided estimates of biomass or carbon stocks,these were either not fully representative or lacked data from important pools such as dead wood(coarse woody debris).The current analysis provides the most complete estimates of carbon stocks and stock changes in natural forests in New Zealand.Results:We present estimates of per hectare carbon stocks and stock changes in live and dead organic matter pools excluding soil carbon based on the first two measurement cycles of the New Zealand Natural Forest Inventory carried out from 2002 to 2014.These show that New Zealand’s natural forests are in balance and are neither a carbon source nor a carbon sink.The average total carbon stock was 227.0±14.4 tC·ha^(−1)(95%C.I.)and did not change significantly in the 7.7 years between measurements with the net annual change estimated to be 0.03±0.18 tC·ha^(−1)·yr^(−1).There was a wide variation in carbon stocks between forest groups.Regenerating forest had an averaged carbon stock of only 53.6±9.4 tC·ha^(−1) but had a significant sequestration rate of 0.63±0.25 tC·ha^(−1)·yr^(−1),while tall forest had an average carbon stock of 252.4±15.5 tC·ha^(−1),but its sequestration rate did not differ significantly from zero(−0.06±0.20 tC·ha^(−1)·yr^(−1)).The forest alliance with the largest average carbon stock in above and below ground live and dead organic matter pools was silver beech-red beech-kamahi forest carrying 360.5±34.6 tC·ha^(−1).Dead wood and litter comprised 27%of the total carbon stock.Conclusions:New Zealand’s Natural Forest Inventory provides estimates of carbon stocks including estimates for difficult to measure pools such as dead wood and roots.It also provides estimates of uncertainties including effects of model prediction error and sampling variation between plots.Importantly it shows that on a national level New Zealand’s natural forests are in balance.Nevertheless,this is a nationally important carbon pool that requires continuous monitoring to identify potential negative or positive changes.
基金jointly supported by the special projects foundation of the National Natural Science Foundation of China(31572209)the Beijing Municipal Sciences and Technology Commission,China(Z141105000614012)the Shanxi Province Science and Technology Research Project,China(20140311008-4)
文摘Organic pollutants, such as polychlorinated dJbenzo-p-dioxins and polychlofinated dibenzofurans （PCDD/Fs）, polychlodnated biphenyls （PCBs）, antibiotics, herbicides, and bisphenol A （BPA）, are commonly found in agricultural environments. They are released into the environment as a result of their use for human health purposes and farm management activities, and are often discharged as waste-water effluents. Most of these organic pollutants are taken up by plants through roots and leaves, and when they enter the tissue, they cause serious damage to the plants. Although the toxicity of organic pollutants to plants, especially to plant cells, has been intensively studied, a systematic review of these studies is lacking. Here we review researches on the toxicity of organic pollutants, their uptake, and translocation in plants. Our objective is to assemble existing knowledge concerning the interaction of organic pollutants with plants, which should be useful for the development of plant-based systems for removing pollutants from aquatic and agricultural environments.
基金supported by the National Natural Science Foundation of China(41271337)the Zhejiang Provincial Natural Science Foundation(LY14E030016)
文摘Objective To identify the bamboo VOCs (volatile organic compounds) effect on animal physiological indices, which associated with human health. Methods GC/MS was used to analyze the volatile organic compounds from Moso bamboo (Phyllostachys heterocyla cv. pubescens). The effect of VOCs on environmental health was evaluated by analyzing the metabolic indices of the type 2 diabetic mouse model. Results Spectra of VOC generated by GC/MS were blasted against an in-house MS library confirming the identification of 33 major components that were manually validated. The relative constituent compounds as a percentage of total VOCs determined were alcohols (34.63%), followed by ether (22.02%), aldehyde (15.84%), ketone (11.47%), ester (4.98%), terpenoid (4.38%), and acids (3.83%). Further experimentation established that the metabolic incidence of the disease can be improved if treated with vanillin, leaf alcohol,β-ionone and methyl salicylate. The effects of these VOCs on type 2 diabetes were evident in the blood lipid and blood glucose levels. Conclusion Our model suggests that VOCs can potentially control the metabolic indices in type 2 diabetes mice. This experiment data also provides the scientific basis for the comprehensive utilization of ornamental bamboos and some reference for other similar study of environmental plants.
基金supported by the National Key Research and Development Program of China(Nos.2017YFD0200707 and 2017YFD0200102)the Fundamental Research Funds for the Central Universities of China(No.2019FZJD007)for Yongchao LIANGthe National Natural Science Foundation of China(No.31800418)for Chang YIN.
文摘Disparities in the substrate affinity and tolerance threshold for ammonia have been believed to play a key role in driving niche differentiation between ammonia-oxidizing archaea (AOA) and bacteria (AOB);however, recent surveys argue that direct competition between AOA and AOB is also important in this phenomenon. Accordingly, it is reasonable to predict that diverse AOA lineages would grow in ammonium (NH_(4)^(+))-rich alkaline arable soils if AOB growth is suppressed. To test this hypothesis, a microcosm study was established using three different types of alkaline arable soils, in which a high NH_(4)^(+) concentration (200 μg N g^(-1) dry soil) was maintained by routinely replenishing urea and the activities of AOB were selectively inhibited by 1-octyne or 3,4-dimethylpyrazole phosphate (DMPP). Compared with amendment with urea alone, 1-octyne partially retarded AOB growth, while DMPP completely inhibited AOB. Both inhibitors accelerated the growth of AOA, with significantly higher ratios of abundance of AOA to AOB observed with DMPP amendment across soils. Nonmetric multidimensional scaling analysis (NMDS) indicated that different treatments significantly altered the community structures of both AOA and AOB and AOA OTUs enriched by high-NH_(4)^(+) amendment were taxonomically constrained across the soils tested and closely related to Nitrososphaera viennensis EN76 and N. garnensis. Given that these representative strains have been demonstrated to be sensitive to high ammonia concentrations, our results suggest that it is the competitiveness for ammonia, rather than disparities in substrate affinity and tolerance threshold for ammonia, that drives niche differentiation between these phylotypes and AOB in NH_(4)^(+)-rich alkaline soils.
基金supported by the National Natural Science Foundation of China (No.30871590)the National Key Basic Research Program (973 Program) of China (Nos.2009CB119003 and 2007CB109305)+1 种基金the Major Research Program of Zhejiang Province (No.2008C12061-1)the National "Eleventh Five Years Plan" Key Project on Science and Technology of China (No.2006BAD05B03)
文摘A hydroponic experiment was carried out to study the effect of elevated carbon dioxide(CO2) on root growth of tomato seedlings.Compared with the control(350 μL L-1),CO2 enrichment(800 μL L-1) significantly increased the dry matter of both shoot and root,the ratio of root to shoot,total root length,root surface area,root diameter,root volume,and root tip numbers,which are important for forming a strong root system.The elevated CO2 treatment also significantly improved root hair development and elongation,thus enhancing nutrient uptake.Increased indole acetic acid concentration in plant tissues and ethylene release in the elevated CO2 treatment might have resulted in root growth enhancement and root hair development and elongation.
基金supported by the National Key Technologies Research and Development Program(2016YFC0501404)the National Natural Science Foundation of China(41461064)
文摘Mixed or chloride salty ions dominate in saline soils, and exert wide-ranging adversely affect on soil biological processes and soil functions. The objectives of this study were to（1） explore the impacts of mixed（0, 3, 6, 10, 20 and 40 g Cl–/SO42–salt/kg dry soil） and chloride（0, 1.5, 3, 5, 8 and 15 g Cl– salt/kg dry soil） salts on soil enzyme activities, soil physiological functional（Biolog） profiles and microbial community structure by using soil enzymatic, Biolog-Eco microplates as well as denaturing gradient gel electrophoresis（DEEG） methods, and（2） determine the threshold concentration of soil electronic conductivity（EC1：5） on maintaining the functional and structural diversity of soil microbial community. The addition of either Cl– or mixed Cl–/SO42–salt obviously increased soil EC, but adversely affected soil biological activities including soil invertase activity, soil microbial biomass carbon（MBC） and substrate-induced respiration（SIR）. Cl– salt showed a greater deleterious influence than mixed Cl–/SO42–salt on soil enzymes and MBC, e.g., the higher soil MBC consistently appeared with Cl–/SO42–instead of Cl– treated soil. Meanwhile, we found that SIR was more reliable than soil basal respiration（SBR） on explaining the changes of soil biological activity responsive to salt disturbance. In addition, microbial community structures of the soil bacteria, fungi, and Bacillus were obviously affected by both salt types and soil EC levels, and its diversity increased with increasing of mixed Cl–/SO42–salt rates, and then sharply declined down after it reached critical point. Moreover, the diversity of fungal community was more sensitive to the mixed salt addition than other groups. The response of soil physiological profiles（Biolog） followed a dose-response pattern with Cl–（R2=0.83） or mixed Cl–/SO42–（R2=0.89） salt. The critical threshold concentrations of salts for soil physiological function were 0.45 d S/m for Cl– and 1.26 d S/m for Cl–/SO42–, and those for soil microbial community structural diversity were 0.70 d S/m for Cl– and 1.75 d S/m for Cl–/SO42–.
基金This study was jointly supported by the National Key R&D Program of China(2018YFD0500206)the National Natural Science Foundation of China(31772395)+1 种基金the Fundamental Research Funds for Central Non-profit Scientific Institutions,China(1610132019046)the Science and Technology Support Project of Langfang,Hebei,China(2019013125).
文摘Oxytetracycline(OTC)residues have been found in soil and water,and they may pose potential risks to agricultural ecological environments.One of the most impactful ways for OTC to enter the soil and water environments is through excrement used as organic fertilizer.Therefore,it is important to remove OTC during manure composting and to understand the transformation of the organic materials during composting in the presence of OTC.In the present paper,chicken manure and wheat sawdust spiked with OTC were composted under different initial moisture contents(MC)to evaluate the degradation of OTC and changes of organic matter during the composting process.The MC has a significant effect on OTC degradation during composting.A higher MC of 65% was more conducive to OTC degradation(77.4%)and compost maturity compared to the lower MC.However,the higher MC of 65%could increase the ammonia volatilization by promoting nitrification compared to the lower MC.An increase in the initial MC could improve the composting temperature.NMR results illustrated that the presence of OTC could affect the internal transformation of aliphatics,and OTC inhibited compost humification.Thus,an initial MC of 55–65% can alleviate the impacts of OTC on humification during manure composting.
基金supported by the Special Fund of Public Industry in China (Agriculture, 200903015)the Science and Technology Project of Hebei Province, China (15227504D)
文摘In this study the transfer characteristics of mercury(Hg)from a wide range of Chinese soils to corn grain(cultivar Zhengdan 958)were investigated.Prediction models were developed for determining the Hg bioconcentration factor(BCF)of Zhengdan 958 from soil,including the soil properties,such as p H,organic matter(OM)concentration,cation exchange capacity(CEC),total nitrogen concentration(TN),total phosphorus concentration(TP),total potassium concentration(TK),and total Hg concentration(THg),using multiple stepwise regression analysis.These prediction models were applied to other non-model corn cultivars using a cross-species extrapolation approach.The results indicated that the soil p H was the most important factor associated with the transfer of Hg from soil to corn grain.Hg bioaccumulation in corn grain increased with the decreasing p H.No significant differences were found between two prediction models derived from different rates of Hg applied to the soil as HgCl2.The prediction models established in this study can be applied to other non-model corn cultivars and are useful for predicting Hg bioconcentration in corn grain and assessing the ecological risk of Hg in different soils.
基金CAMG was funded with a Lincoln University Ph D scholarship(Lincoln University Centennial Trust,New Zealand)with research funding from the New Zealand Hereford Association(NZHA)the Hellaby Grasslands Trust。
文摘Background:The grazing behaviour of herbivores and their grazing personalities might in part be determined genetically,but there are few studies in beef cattle illustrating this.In this study,we investigated for first time the genetic variation within a candidate‘grazing gene',the glutamate metabotropic receptor 5 gene(GRM5),and tested associations between variation in that gene and variation in grazing personality behaviours(GP-behaviours)displayed by free-ranging cows during winter grazing in the steep and rugged rangelands of New Zealand.Mature beef cows(n=303,from 3 to 10 years of age)were tracked with global positioning system(GPS)and,with 5-minutes(min)relocation frequency,various GP-behaviours were calculated.These included horizontal and vertical distances travelled,mean elevation,elevation range,elevation gain,slope,home range and movement tortuosity,variously calculated using daily relocation trajectories with repeated measurements(i.e.,7 to 24 days(d))and satellite-derived digital elevation models(DEM).The different GP-behaviours were fitted into mixed models to ascertain their associations with variant sequences and genotypes of GRM5.Results:We discovered three GRM5 variants(A,B and C)and identified the six possible genotypes in the cattle studied.The mixed models revealed that A was significantly associated with elevation range,home range and movement tortuosity.Similarly,GRM5 genotypes were associated(P<0.05)to home range and movement tortuosity,while trends suggesting association(P<0.1)were also revealed for elevation range and horizontal distance travelled.Most GP-behaviour models were improved by correcting for cow age-class as a fixed factor.The analysis of GP-behaviours averaged per cow age-class suggests that grazing personality is fully established as beef cows reached 4 years of age.Home range and movement tortuosity were not only associated with GRM5 variation,but also negatively correlated with each other(r=-0.27,P<0.001).Conclusions:There seems to be a genetically determined trade-off between home range and movement tortuosity that may be useful in beef cattle breeding programmes aiming to improve the grazing distribution and utilisation of steep and rugged rangelands.
基金This work was supported by Core Premium Kiwifruit funding.
文摘Exogenous application of a cytokinin-like compound forchlorfenuron(CPPU)can promote fruit growth,although often at the expense of dry matter(DM),an important indicator of fruit quality.Actinidia chinensis var.deliciosa‘Hayward’fruit are very responsive to CPPU treatments,but the mechanism underlying the significant fruit weight increase and associated decrease in DM is unclear.In this study,we hypothesised that CPPU-enhanced growth increases fruit carbohydrate demand,but limited carbohydrate supply resulted in decreased fruit DM.During fruit development,CPPU effects on physical parameters,metabolites,osmotic pressure and transcriptional changes were assessed under conditions of both standard and a high carbohydrate supply.We showed that CPPU increased fruit fresh weight but the dramatic DM decrease was not carbohydrate limited.Enhanced glucose and fructose concentrations contributed to an increase in soluble carbohydrate osmotic pressure,which was correlated with increased water accumulation in CPPU-treated fruit and up-regulation of water channel aquaporin gene PIP2.4 at 49 days after anthesis.Transcipt analysis suggested that the molecular mechanism contributing to increased glucose and fructose concentrations was altered by carbohydrate supply.At standard carbohydrate supply,the early glucose increase in CPPU fruit was associated with reduced starch synthesis and increased starch degradation.When carbohydrate supply was high,the early glucose increase in CPPU fruit was associated with a general decrease in starch synthesis but up-regulation of vacuolar invertase and fructokinase genes.We conclude that CPPU affected fruit expansion by increasing the osmotically-driven water uptake and its effect was not carbohydrate supply-limited.
基金The Ministry of Business,Innovation and Employment,New Zealand provided funding(contract no.C03X0902)for this research.
文摘Background:Forest management practices(e.g.choice of stand density,fertilisation)are just as important in carbon(C)forestry as in other types of forestry and will affect the level of C sequestration and profitability.Because C stored in wood is approximately proportional to the product of its volume and density,it is necessary to account for both volume growth and wood density when assessing the effects of fertilisation on C sequestration in pine forests.Methods:The effects of nitrogen(N)input from biosolids application on forest C sequestration were quantified from an intensively monitored biosolids field trial in a Pinus radiata plantation on a sandy soil in New Zealand.The field trial tested the application of three biosolids rates:Control(no application),Standard(300 kg N⋅ha^(-1) applied every three years),and High(600 kg N⋅ha^(-1) applied every three years),across three levels of stand density:300,450,and 600 stems⋅ha^(-1).Carbon sequestration was estimated using the C-Change model from annual plot measurements of stand density,stem height and diameter,and annual breast height wood densities obtained from increment cores.Results:By age 24 years,N-fertilised trees had sequestered 40 t C⋅ha^(-1) more than unfertilised trees,an increase of 18%.Fertilisation increased stem volume by 23%but reduced stem wood density by 2.5%.Most of the increased C sequestration occurred between age 6 and age 17 years and the Standard rate gave the same increase in C sequestration as the High rate.On average,there was no significant difference in growth rate between fertilised and unfertilised trees after the 17th growth year,but the increased growth ceased earlier at higher stand densities,and later at lower stand densities.Conclusions:This study indicates that 2–3 applications of the Standard rate would have been sufficient to achieve the increased C sequestration,with an applied N to C conversion ratio of 43–65 kg C⋅kg^(-1) N.Our results highlight that N fertilisation will become more widespread under greenhouse gas emissions trading schemes which en-courages forest management practices that improve C sequestration in young forests in New Zealand in particular and other countries in general.
文摘Chitosan oligomers （average Dp-4） are known for their antifungal activity and wood decay resistance. These oligomers are susceptible to moisture, and promote yeast growth upon air exposure after a sufficient length of time. Chitosan oligomers of three different states viz. completely dried, freshly prepared and highly viscous form, were prepared to compare their in-vitro antifungal activities against three brown-rot fungi, two sapstain and one mould fungus using agar nutrient medium. Additionally, a mixture of chitosan oligomers and boric acid was used for wood treatment. The nutrient medium bioassay results show that all states of chitosan oligomers inhibited the growth of tested basidiomycetes fungi, but not sapstain and mould fungi. Subsequently, wood decay results confirm antifungal activity of chitosan oligomers plus boron against basidiomycetes, but highlighted their leachability upon water exposure.
文摘A competitive co-evolutionary Multi-Objective Genetic Algorithm (cc-MOGA) was used to approximate a Pareto front of efficient silvicultural regimes for Eucalyptus fastigata. The three objectives to be maximised included, sawlog, pulpwood and carbon sequestration payment. Three carbon price scenarios (3CPS), i.e. NZ $25, NZ $50 and NZ $100 for a tonne of CO2 sequestered, were used to assess the impact on silvicultural regimes, against a fourth non-carbon Pareto set of efficient regimes (nonCPS), determined from a cc-MOGA with two objectives, i.e. competing sawlog and pulpwood productions. Carbon prices included in stand valuation were found to influence the silvicultural regimes by increasing the rotation length and lowering the final crop number before clearfell. However, there were no significant changes in the frequency, timing, and intensity of thinning operations amongst all the four Pareto sets of solutions. However, the 3CPS were not significantly different from each other, which meant that these silvicultural regimes were insensitive to the price of carbon. This was because maximising carbon sequestration was directly related to the biological growth rate. As such an optimal mix of frequency, intensity, and timing of thinning maintained maximum growth rate for as long as possible for any one rotation.
文摘Restoration of grassland such as exclusion of grazing has been considered to increase aboveground plant diversity and soil fertility. However, knowledge on the effect of long-term exclusion of grazing on soil bacterial community structure and diversity is not well understood. The two sites were selected in the Inner Mongolian grassland, i.e., one fenced off since 1979 (UG79) and the other continually grazed by sheep (FG) all along. Soil microbial biomass was measured using fumigation method and bacterial community structure and diversity were assessed using methods of Denaturing Gradient Gel Electrophoresis (DGGE) and clone library. Results showed that the UG79 soil had significantly higher microbial biomass carbon and nitrogen compared with the FG soil. There was a clear separation in soil bacterial community structure, but not in bacterial diversity between the two sites. Moreover, 55 clones from the UG79 soil and 56 clones from the FG soil were selected and sequenced. Phylogenetic analysis of all clone sequences indicated that bacterial communities were dominated by the groups of Actinomycetes, Proteobacteria and Bacteroidetes, but there were no significant differences in bacterial diversity between the two sites, consistent with the results obtained from DGGE. The results highlighted that although long-term exclusion of grazing increased soil microbial biomass, but it did not harbor higher bacterial diversity compared with freely grazed site.
