The aim was to explore the linear regression prediction models between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum in autumn idle land. [Method] The relationships between sowing tim...The aim was to explore the linear regression prediction models between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum in autumn idle land. [Method] The relationships between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum were simulated and compared by employing field plot experiment and linear regression analysis. [Result] The sowing time had a great impact on plant height, leaf stem ratio and DW/FW ratio of forage sorghum in autumn idle land. With the delay of sowing time, the plant height and DW/FW ratio of forage sorghum decreased, while the leaf stem ratio increased. The regression models between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum were established： plant height and sowing time, yheight = 234.725- 5.005X; leaf stem ratio and sowing time,ylcaf= 0.096 ＋ 0,019x; DW/FW ratio and sowing time, ydry= 0.305-0.002X. From July 23rd to August 30th, the plant height of forage sorghum was reduced by 5.005 cm, the leaf stem ratio was increased by 0.019 and the DW/FW ratio was reduced by 0.002 in average when hhe sowing time was delayed by one day. [Conclusion] This study provides a theoretical support for the production of forage sorghum in autumn idle land.展开更多
Nitrogen(N)and phosphorus(P)are two essential nutrients that determine plant growth and many nutrient cycling processes.Increasing N and P deposition is an important driver of ecosystem changes.However,in contrast to ...Nitrogen(N)and phosphorus(P)are two essential nutrients that determine plant growth and many nutrient cycling processes.Increasing N and P deposition is an important driver of ecosystem changes.However,in contrast to numerous studies about the impacts of nutrient addition on forests and temperate grasslands,how plant foliar stoichiometry and nutrient resorption respond to N and P addition in alpine grasslands is poorly understood.Therefore,we conducted an N and P addition experiment(involving control,N addition,P addition,and N+P addition)in an alpine grassland on Kunlun Mountains(Xinjiang Uygur Autonomous Region,China)in 2016 and 2017 to investigate the changes in leaf nutrient concentrations(i.e.,leaf N,Leaf P,and leaf N:P ratio)and nutrient resorption efficiency of Seriphidium rhodanthum and Stipa capillata,which are dominant species in this grassland.Results showed that N addition has significant effects on soil inorganic N(NO_(3)^(-)-N and NH_(4)^(+)-N)and leaf N of both species in the study periods.Compared with green leaves,leaf nutrient concentrations and nutrient resorption efficiency in senesced leaves of S.rhodanthum was more sensitive to N addition,whereas N addition influenced leaf N and leaf N:P ratio in green and senesced leaves of S.capillata.N addition did not influence N resorption efficiency of the two species.P addition and N+P addition significantly improved leaf P and had a negative effect on P resorption efficiency of the two species in the study period.These influences on plants can be explained by increasing P availability.The present results illustrated that the two species are more sensitive to P addition than N addition,which implies that P is the major limiting factor in the studied alpine grassland ecosystem.In addition,an interactive effect of N+P addition was only discernable with respect to soil availability,but did not affect plants.Therefore,exploring how nutrient characteristics and resorption response to N and P addition in the alpine grassland is important to understand nutrient use strategy of plants in terrestrial ecosystems.展开更多
[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] ...[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] Effects of such two influencing factors as line spacing and seedling density on the leaf-stem ratio, DW/FW ratio and grass yield of forage sweet sorghum were analyzed by using split-plot experiment design experiment method and LSD method of IBM. SPSS. Statis- tics. v22 stati, stics software. [ Results ~ Seedling density and line spacing had no obvious effect on the leaf-stem ratio and DW/FW ratio of forage sweet sorghum but had obvious influences on the grass yield. Moreover, the optimal combination of seedling density and line spacing for high yield of forage sweet sorghum was A2 B4, that is, seedling density was 225 000 plants/hm2, and line spacing was 40 cm. [ Conclusions] The results provided a theoretical basis and technical support for high-yield cultivation techniques of forage sweet sorghum.展开更多
The study was performed with seven groundnut varieties/genotypes and F1s derived from crossing in all possible combinations without reciprocal among the mentioned varieties/genotypes. The objective was to assess wheth...The study was performed with seven groundnut varieties/genotypes and F1s derived from crossing in all possible combinations without reciprocal among the mentioned varieties/genotypes. The objective was to assess whether low Ca2＋ content and Ca2＋/Na＋ ratio of leaf tissue or stem tissue determine salinity tolerance in terms of economic yield （kernel yield） in groundnut. It revealed that the varieties, “Binachinabadam-6”, “Binachinabadam-5” and the F1 G2 × G3 were most tolerant based on kernel yield under 8 dS/m and 10 dS/m salinity stresses. These two tolerant varieties and the F1 also showed lower Ca2＋ and Ca2＋/Na＋ ratios in leaf tissue, which indicated lower Ca2＋ and Ca2＋/Na＋ ratio of leaf tissue determined salinity tolerance in terms of kernel yield in Spanish type groundnut. These findings could be applied in future plant breeding applications for screening salt tolerant Spanish type groundnut genotypes.展开更多
Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on c...Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season.展开更多
Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of bas...Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of basal internodes persists.The objectives of this study were(1)to identify key factors affecting the elongation of basal internodes and(2)to establish a quantitative relationship between basal internode length and canopy indices.An inbred rice cultivar,Yinjingruanzhan,was grown in two split-plot field experiments with three N rates(0,75,and 150 kg N ha−1 in early season and 0,90,and 180 kg N ha−1 in late season)as main plots,three seedling densities(16.7,75.0,and 187.5 seedlings m−2)as subplots,and three replications in the 2015 early and late seasons in Guangzhou,China.Light intensity at base of canopy(Lb),light quality as determined from red/far-red light ratio(R/FR),light transmission ratio(LTR),leaf area index(LAI),leaf N concentration(NLV)and final length of second internode(counted from soil surface upward)(FIL)were recorded.Higher N rate and seedling density resulted in significantly longer FIL.FIL was negatively correlated with Lb,LTR,and R/FR(P<0.01)and positively correlated with LAI(P<0.01),but not correlated with NLV(P>0.05).Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI(R2=0.82).Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL.We conclude that FIL is determined mainly by Lb and LAI at jointing stage.NLV has no direct effect on the elongation of basal internodes.N application indirectly affects FIL by changing LAI and light conditions in the rice canopy.Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice.展开更多
Plant residue application is an important way to maintain soil productivity. In order to determine whether walnut leaf can be returned to soil or not and get the conditions of efficient decomposition, the effect of wa...Plant residue application is an important way to maintain soil productivity. In order to determine whether walnut leaf can be returned to soil or not and get the conditions of efficient decomposition, the effect of walnut （Juglans sigillata Dode） leaf decomposition under various conditions （different temperatures, durations and leaf-soil ratios） upon soil chemicals and biological properties were analyzed. Compared with the original soil, adding walnut leaf to soil could decrease soil pH, increase EC, nutrient contents, microbial quantity and enzyme activities. Total nitrogen, total organic carbon and organic matter increased with the increasing of decomposition duration, temperature and leaf-soil ratio. Enzyme activities changed with different decomposition conditions, but the highest activities of alkaline phosphatase and catalase were associated with the lower temperature （15℃）, the highest concentration （10 ： 100） and the shortest duration （0 day）. Walnut leaves decomposition for 20 or 30 days at 15℃ and with 10 ： 100 ratio significantly promoted bacteria, fungi and the total microbial quantity. Walnut leaves can be returned to soil because their decomposition could improve relevant indicators of soil fertility, decomposition conditions as shorter durations （20 days）, lower temperature （ 15 ℃） and higher concentrations of leaves （ 10 ： 100） were the more effective decomposition conditions for walnut leaves.展开更多
Variations in leaf morphology and stomatal characteristics have been extensively studied at both inter- and intraspecific levels although not explicitly in the context of paper birch (Betula papyrifera Marsh) populati...Variations in leaf morphology and stomatal characteristics have been extensively studied at both inter- and intraspecific levels although not explicitly in the context of paper birch (Betula papyrifera Marsh) populations. The birch populations might have developed the leaf variations that allowed them to adapt to a wide climatic gradient. Therefore, in this study we examined variations in the leaf morphological and stomatal characteristics of sixteen paper birch populations collected across Canada and grown in a common garden. We also examined the relationship between these leaf characteristics and the climate of the population’s origin. Significant genotypic differences were found in the leaf characteristics measured among the birch populations. Thus, we expected that the observed leaf variations may be partly explained as natural diversity in the birch due to differences in environment of origin. We noticed that along mean annual precipitation and aridity gradients, hair density on leaf adaxial surface had decreased whereas stomatal density increased significantly. Our results showed that the populations with larger leaf area and specific leaf area had higher hair density but low stomatal density. These leaf characteristics provided a structural basis in reducing water loss through leaves and increasing water use efficiency. A trade-off between stomatal area and density resulted in this study might be a strategy of the birch to balance stomatal conductance in decreased precipitation.展开更多
An allelic sorghum [Sorghum bicolor (L.) Moench] mutant with thick and narrow erect leaves (Thl) and reduced adaxial stomatal density was isolated from the Annotated Individually pedigreed Mutagenized Sorghum mutant l...An allelic sorghum [Sorghum bicolor (L.) Moench] mutant with thick and narrow erect leaves (Thl) and reduced adaxial stomatal density was isolated from the Annotated Individually pedigreed Mutagenized Sorghum mutant library developed at the Plant Stress and Germplasm Development Unit at Lubbock TX. The mutant, Thl, was isolated from a pedigreed M3 family generated by ethyl methanesulfonate mutagenization from an elite inbred sorghum line, BTx623, which had been used to sequence the sorghum genome. The mutant has been backcrossed to the wild-type BTx623 confirming that the trait results derive from a stable recessive nuclear gene mutation. Herein, we briefly described morphological and selected physiological characteristics of this mutant sorghum.展开更多
Two-year field experiments were conducted at Linqing, Yellow River valley of China, to study the plant response to the removal of early fruiting branches in transgenic Bt （Bacillus thuringiensis） cotton （Gossypium ...Two-year field experiments were conducted at Linqing, Yellow River valley of China, to study the plant response to the removal of early fruiting branches in transgenic Bt （Bacillus thuringiensis） cotton （Gossypium hirsutum L.） from 2003 to 2004. Plants were undamaged and treated by removing two basal fruiting branches （FB） at squaring to form the control and the removal treatment, respectively. The plant height, leaf area （LA）, dry weight of fruiting forms （DWFF）, the number of fruiting nodes （NFN）, photosynthetic （Pn） rate, and levels of leaf chlorophyll （Chl）, N, P, K, and Cry lAc protein in main- stem leaves were measured at a 10- or 20-d interval after FB removal, and the sink/source ratio as indicated by NFN/LA and DWFF/LA was determined. FB removal significantly increased the plant height, LA, and plant biomass in both years. Lint yields were increased 7.5 and 5.2% by removal compared with their controls in 2003 and 2004, respectively. Significant increases in boll size （5.7 and 5.1%） were also observed in removal than in control for both years. Either NFN/LA or DWFF/LA was significantly reduced by removal before 40 d after removal; however, both NFN/LA and DWFF/LA were significantly enhanced by FB removal at 80 d after removal compared to the untreated control. There was no significant difference in fiber quality in the first two harvests between removal and control, but fiber strength and micronarie in the third harvest were significantly improved by FB removal. In terms of leaf Chl, Pn rate, levels of total N, P, and K in late season, leaf senescence was considerably delayed by FB removal. Levels of CrylAc protein in the fully expanded young leaves were considerably higher in FB-excised plants than in control, indicating FB removal enhanced CrylAc expression. It is suggested that the yield and quality improvement with FB removal may be attributed to the increased NFN/LA or DWFF/LA in late season and delayed leaf senescence, respectively. FB removal can be a potential practice incorporated into the intensive cultivation system for enhancing transgenic Bt cotton production.展开更多
Two tolerant (BB24 and BB43) and two susceptible (BARI busbean-2 and BB04) genotypes of common bean (Phaseolus vulgaris L.) were evaluated for their water status and its relationship with reproductive responses under ...Two tolerant (BB24 and BB43) and two susceptible (BARI busbean-2 and BB04) genotypes of common bean (Phaseolus vulgaris L.) were evaluated for their water status and its relationship with reproductive responses under continuous water stress (50% field capacity) and control (80% field capacity) conditions in a net house covered with polyethylene sheet at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh. Under water stress condition, the susceptible genotype namely BB04 exhibited more negative leaf water potential (LWP) which was followed by that of BARI bushbean-2 in all the time of the day except at noon. The tolerant genotype namely BB24 exhibited less negative LWP at noon. The tolerant genotypes maintained higher relative water content (WRC) than the susceptible ones from dawn to dusk. The relationship between RWC and LWP was examined separately for four genotypes under water stress condition. The genotype BB24 showed a smaller decrease in RWC with more negative LWP than BB04. Water stress reduced pod setting ratio. The relationship between the leaf water status and reproductive responses showed that the genotype with a little reduction in mid-day drop of RWC or with high mid-day RWC displayed a high pod setting ratio.展开更多
Generally, plant species with shorter leaf longevity maintain a positive carbon balance by decreasing leaf mass per area (LMA) and increasing photosynthesis. However, plants at high elevations need to increase LMA aga...Generally, plant species with shorter leaf longevity maintain a positive carbon balance by decreasing leaf mass per area (LMA) and increasing photosynthesis. However, plants at high elevations need to increase LMA against environmental stresses. Therefore, plants need to increase both LMA and photosynthesis at high elevations. To examine how deciduous plants maintain a positive carbon balance at high elevations, photosynthesis and related leaf traits for deciduous broad-leaved tree Betula ermanii were measured at three elevations. LMA was greater at middle and high elevations than at low elevation. Leaf δ13C was greater at higher elevations, and positively correlated with LMA, indicating greater long-term deficiency of CO2 in leaves at higher elevations. However, the Ci/Ca ratio at photosynthetic measurement was not low at high elevations. Nitrogen content per leaf mass and stomatal conductance were greater at higher elevations. Photosynthetic rates and photosynthetic nitrogen use efficiency (PNUE) did not differ among the three elevations. Photosynthetic rate showed a strong positive correlation with stomatal conductance on a leaf area basis (R2 = 0.83, P < 0.001). Therefore, this study suggests B. ermanii compensates the deficiency of CO2 in leaves at high elevation by increasing stomatal conductance, and maintains photosynthesis and PNUE at high elevation as much as at low elevation.展开更多
An experiment was conducted at Rice Research Institute, Kala Shah Kaku in 2010 during kharif season to study the influence of nitrogen (N) and potash (K) on severity of Bacterial leaf blight (BLB) of rice (Oryza sativ...An experiment was conducted at Rice Research Institute, Kala Shah Kaku in 2010 during kharif season to study the influence of nitrogen (N) and potash (K) on severity of Bacterial leaf blight (BLB) of rice (Oryza sativa L.) aimed at improving productivity. The experiment was laid out in randomized complete block design with factorial arrangement with three replications. Treatments comprised of: 0 kg N ha-1, 75 kg N ha-1, 100 kg N ha-1, 125 kg N ha-1 and 0 kg K ha-1, 50 kg K ha-1, 75 kg K ha-1, 100 kg K ha-1. Data on disease severity and paddy yield were recorded using standard procedures. Paddy yield was affected significantly by various combinations of N & K. In case of bacterial leaf blight, minimum diseased incidence percentage was observed when nitrogen alone was applied @ 75 kg·ha-1 in contrast to fertilizer applied @ 125 kg N ha-1 + 50 kg K ha-1 which showed maximum diseased incidence percentage. Maximum paddy yield (4.32 t·ha-1 ) was recorded when rice was fertilized @ 75 kg N ha-1 + 100 kg K ha-1 as compared to sole fertilization of 75 kg K ha-1 that produced minimum paddy yield (2.40 t·ha-1). Maximum gross income, net returns and benefit cost ratio were obtained where rice crop was fertilized @ 75 kg N ha-1 and 100 kg K ha-1.展开更多
文摘The aim was to explore the linear regression prediction models between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum in autumn idle land. [Method] The relationships between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum were simulated and compared by employing field plot experiment and linear regression analysis. [Result] The sowing time had a great impact on plant height, leaf stem ratio and DW/FW ratio of forage sorghum in autumn idle land. With the delay of sowing time, the plant height and DW/FW ratio of forage sorghum decreased, while the leaf stem ratio increased. The regression models between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum were established： plant height and sowing time, yheight = 234.725- 5.005X; leaf stem ratio and sowing time,ylcaf= 0.096 ＋ 0,019x; DW/FW ratio and sowing time, ydry= 0.305-0.002X. From July 23rd to August 30th, the plant height of forage sorghum was reduced by 5.005 cm, the leaf stem ratio was increased by 0.019 and the DW/FW ratio was reduced by 0.002 in average when hhe sowing time was delayed by one day. [Conclusion] This study provides a theoretical support for the production of forage sorghum in autumn idle land.
基金This research was supported by the National Natural Science Foundation of China(41807335)the Shandong Provincial Natural Science Foundation,China(ZR2020MC040)+2 种基金the National Key Technology Research and Development Program of China(2019YFC0507602-2)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2020434)the National Postdoctoral Program for Innovative Talents(BX201700279).
文摘Nitrogen(N)and phosphorus(P)are two essential nutrients that determine plant growth and many nutrient cycling processes.Increasing N and P deposition is an important driver of ecosystem changes.However,in contrast to numerous studies about the impacts of nutrient addition on forests and temperate grasslands,how plant foliar stoichiometry and nutrient resorption respond to N and P addition in alpine grasslands is poorly understood.Therefore,we conducted an N and P addition experiment(involving control,N addition,P addition,and N+P addition)in an alpine grassland on Kunlun Mountains(Xinjiang Uygur Autonomous Region,China)in 2016 and 2017 to investigate the changes in leaf nutrient concentrations(i.e.,leaf N,Leaf P,and leaf N:P ratio)and nutrient resorption efficiency of Seriphidium rhodanthum and Stipa capillata,which are dominant species in this grassland.Results showed that N addition has significant effects on soil inorganic N(NO_(3)^(-)-N and NH_(4)^(+)-N)and leaf N of both species in the study periods.Compared with green leaves,leaf nutrient concentrations and nutrient resorption efficiency in senesced leaves of S.rhodanthum was more sensitive to N addition,whereas N addition influenced leaf N and leaf N:P ratio in green and senesced leaves of S.capillata.N addition did not influence N resorption efficiency of the two species.P addition and N+P addition significantly improved leaf P and had a negative effect on P resorption efficiency of the two species in the study period.These influences on plants can be explained by increasing P availability.The present results illustrated that the two species are more sensitive to P addition than N addition,which implies that P is the major limiting factor in the studied alpine grassland ecosystem.In addition,an interactive effect of N+P addition was only discernable with respect to soil availability,but did not affect plants.Therefore,exploring how nutrient characteristics and resorption response to N and P addition in the alpine grassland is important to understand nutrient use strategy of plants in terrestrial ecosystems.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(20120304201)
文摘[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] Effects of such two influencing factors as line spacing and seedling density on the leaf-stem ratio, DW/FW ratio and grass yield of forage sweet sorghum were analyzed by using split-plot experiment design experiment method and LSD method of IBM. SPSS. Statis- tics. v22 stati, stics software. [ Results ~ Seedling density and line spacing had no obvious effect on the leaf-stem ratio and DW/FW ratio of forage sweet sorghum but had obvious influences on the grass yield. Moreover, the optimal combination of seedling density and line spacing for high yield of forage sweet sorghum was A2 B4, that is, seedling density was 225 000 plants/hm2, and line spacing was 40 cm. [ Conclusions] The results provided a theoretical basis and technical support for high-yield cultivation techniques of forage sweet sorghum.
文摘The study was performed with seven groundnut varieties/genotypes and F1s derived from crossing in all possible combinations without reciprocal among the mentioned varieties/genotypes. The objective was to assess whether low Ca2＋ content and Ca2＋/Na＋ ratio of leaf tissue or stem tissue determine salinity tolerance in terms of economic yield （kernel yield） in groundnut. It revealed that the varieties, “Binachinabadam-6”, “Binachinabadam-5” and the F1 G2 × G3 were most tolerant based on kernel yield under 8 dS/m and 10 dS/m salinity stresses. These two tolerant varieties and the F1 also showed lower Ca2＋ and Ca2＋/Na＋ ratios in leaf tissue, which indicated lower Ca2＋ and Ca2＋/Na＋ ratio of leaf tissue determined salinity tolerance in terms of kernel yield in Spanish type groundnut. These findings could be applied in future plant breeding applications for screening salt tolerant Spanish type groundnut genotypes.
文摘Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season.
基金supported by the Natural Science Foundation of Guangdong Province,China(S2012020011043)the National High Technology Research and Development Program of China(2014AA10A605)+2 种基金the Special Fund for Agro-scientific Research in the Public Interest(201503106)Modern Agriculture Industry Technology System for Rice in Guangdong Province(2016LM1066,2017LM1066,2018LM1066)the Swiss Agency for Development and Cooperation through its funding of “Closing Rice Yield Gaps in Asia” Project(CORIGAP)
文摘Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of basal internodes persists.The objectives of this study were(1)to identify key factors affecting the elongation of basal internodes and(2)to establish a quantitative relationship between basal internode length and canopy indices.An inbred rice cultivar,Yinjingruanzhan,was grown in two split-plot field experiments with three N rates(0,75,and 150 kg N ha−1 in early season and 0,90,and 180 kg N ha−1 in late season)as main plots,three seedling densities(16.7,75.0,and 187.5 seedlings m−2)as subplots,and three replications in the 2015 early and late seasons in Guangzhou,China.Light intensity at base of canopy(Lb),light quality as determined from red/far-red light ratio(R/FR),light transmission ratio(LTR),leaf area index(LAI),leaf N concentration(NLV)and final length of second internode(counted from soil surface upward)(FIL)were recorded.Higher N rate and seedling density resulted in significantly longer FIL.FIL was negatively correlated with Lb,LTR,and R/FR(P<0.01)and positively correlated with LAI(P<0.01),but not correlated with NLV(P>0.05).Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI(R2=0.82).Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL.We conclude that FIL is determined mainly by Lb and LAI at jointing stage.NLV has no direct effect on the elongation of basal internodes.N application indirectly affects FIL by changing LAI and light conditions in the rice canopy.Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice.
基金Supported by Guizhou Science and Technology Major Project([2011]6011)the National Key Technology R&D Program(2014BAD23B03)
文摘Plant residue application is an important way to maintain soil productivity. In order to determine whether walnut leaf can be returned to soil or not and get the conditions of efficient decomposition, the effect of walnut （Juglans sigillata Dode） leaf decomposition under various conditions （different temperatures, durations and leaf-soil ratios） upon soil chemicals and biological properties were analyzed. Compared with the original soil, adding walnut leaf to soil could decrease soil pH, increase EC, nutrient contents, microbial quantity and enzyme activities. Total nitrogen, total organic carbon and organic matter increased with the increasing of decomposition duration, temperature and leaf-soil ratio. Enzyme activities changed with different decomposition conditions, but the highest activities of alkaline phosphatase and catalase were associated with the lower temperature （15℃）, the highest concentration （10 ： 100） and the shortest duration （0 day）. Walnut leaves decomposition for 20 or 30 days at 15℃ and with 10 ： 100 ratio significantly promoted bacteria, fungi and the total microbial quantity. Walnut leaves can be returned to soil because their decomposition could improve relevant indicators of soil fertility, decomposition conditions as shorter durations （20 days）, lower temperature （ 15 ℃） and higher concentrations of leaves （ 10 ： 100） were the more effective decomposition conditions for walnut leaves.
文摘Variations in leaf morphology and stomatal characteristics have been extensively studied at both inter- and intraspecific levels although not explicitly in the context of paper birch (Betula papyrifera Marsh) populations. The birch populations might have developed the leaf variations that allowed them to adapt to a wide climatic gradient. Therefore, in this study we examined variations in the leaf morphological and stomatal characteristics of sixteen paper birch populations collected across Canada and grown in a common garden. We also examined the relationship between these leaf characteristics and the climate of the population’s origin. Significant genotypic differences were found in the leaf characteristics measured among the birch populations. Thus, we expected that the observed leaf variations may be partly explained as natural diversity in the birch due to differences in environment of origin. We noticed that along mean annual precipitation and aridity gradients, hair density on leaf adaxial surface had decreased whereas stomatal density increased significantly. Our results showed that the populations with larger leaf area and specific leaf area had higher hair density but low stomatal density. These leaf characteristics provided a structural basis in reducing water loss through leaves and increasing water use efficiency. A trade-off between stomatal area and density resulted in this study might be a strategy of the birch to balance stomatal conductance in decreased precipitation.
文摘An allelic sorghum [Sorghum bicolor (L.) Moench] mutant with thick and narrow erect leaves (Thl) and reduced adaxial stomatal density was isolated from the Annotated Individually pedigreed Mutagenized Sorghum mutant library developed at the Plant Stress and Germplasm Development Unit at Lubbock TX. The mutant, Thl, was isolated from a pedigreed M3 family generated by ethyl methanesulfonate mutagenization from an elite inbred sorghum line, BTx623, which had been used to sequence the sorghum genome. The mutant has been backcrossed to the wild-type BTx623 confirming that the trait results derive from a stable recessive nuclear gene mutation. Herein, we briefly described morphological and selected physiological characteristics of this mutant sorghum.
文摘Two-year field experiments were conducted at Linqing, Yellow River valley of China, to study the plant response to the removal of early fruiting branches in transgenic Bt （Bacillus thuringiensis） cotton （Gossypium hirsutum L.） from 2003 to 2004. Plants were undamaged and treated by removing two basal fruiting branches （FB） at squaring to form the control and the removal treatment, respectively. The plant height, leaf area （LA）, dry weight of fruiting forms （DWFF）, the number of fruiting nodes （NFN）, photosynthetic （Pn） rate, and levels of leaf chlorophyll （Chl）, N, P, K, and Cry lAc protein in main- stem leaves were measured at a 10- or 20-d interval after FB removal, and the sink/source ratio as indicated by NFN/LA and DWFF/LA was determined. FB removal significantly increased the plant height, LA, and plant biomass in both years. Lint yields were increased 7.5 and 5.2% by removal compared with their controls in 2003 and 2004, respectively. Significant increases in boll size （5.7 and 5.1%） were also observed in removal than in control for both years. Either NFN/LA or DWFF/LA was significantly reduced by removal before 40 d after removal; however, both NFN/LA and DWFF/LA were significantly enhanced by FB removal at 80 d after removal compared to the untreated control. There was no significant difference in fiber quality in the first two harvests between removal and control, but fiber strength and micronarie in the third harvest were significantly improved by FB removal. In terms of leaf Chl, Pn rate, levels of total N, P, and K in late season, leaf senescence was considerably delayed by FB removal. Levels of CrylAc protein in the fully expanded young leaves were considerably higher in FB-excised plants than in control, indicating FB removal enhanced CrylAc expression. It is suggested that the yield and quality improvement with FB removal may be attributed to the increased NFN/LA or DWFF/LA in late season and delayed leaf senescence, respectively. FB removal can be a potential practice incorporated into the intensive cultivation system for enhancing transgenic Bt cotton production.
文摘Two tolerant (BB24 and BB43) and two susceptible (BARI busbean-2 and BB04) genotypes of common bean (Phaseolus vulgaris L.) were evaluated for their water status and its relationship with reproductive responses under continuous water stress (50% field capacity) and control (80% field capacity) conditions in a net house covered with polyethylene sheet at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh. Under water stress condition, the susceptible genotype namely BB04 exhibited more negative leaf water potential (LWP) which was followed by that of BARI bushbean-2 in all the time of the day except at noon. The tolerant genotype namely BB24 exhibited less negative LWP at noon. The tolerant genotypes maintained higher relative water content (WRC) than the susceptible ones from dawn to dusk. The relationship between RWC and LWP was examined separately for four genotypes under water stress condition. The genotype BB24 showed a smaller decrease in RWC with more negative LWP than BB04. Water stress reduced pod setting ratio. The relationship between the leaf water status and reproductive responses showed that the genotype with a little reduction in mid-day drop of RWC or with high mid-day RWC displayed a high pod setting ratio.
文摘Generally, plant species with shorter leaf longevity maintain a positive carbon balance by decreasing leaf mass per area (LMA) and increasing photosynthesis. However, plants at high elevations need to increase LMA against environmental stresses. Therefore, plants need to increase both LMA and photosynthesis at high elevations. To examine how deciduous plants maintain a positive carbon balance at high elevations, photosynthesis and related leaf traits for deciduous broad-leaved tree Betula ermanii were measured at three elevations. LMA was greater at middle and high elevations than at low elevation. Leaf δ13C was greater at higher elevations, and positively correlated with LMA, indicating greater long-term deficiency of CO2 in leaves at higher elevations. However, the Ci/Ca ratio at photosynthetic measurement was not low at high elevations. Nitrogen content per leaf mass and stomatal conductance were greater at higher elevations. Photosynthetic rates and photosynthetic nitrogen use efficiency (PNUE) did not differ among the three elevations. Photosynthetic rate showed a strong positive correlation with stomatal conductance on a leaf area basis (R2 = 0.83, P < 0.001). Therefore, this study suggests B. ermanii compensates the deficiency of CO2 in leaves at high elevation by increasing stomatal conductance, and maintains photosynthesis and PNUE at high elevation as much as at low elevation.
文摘An experiment was conducted at Rice Research Institute, Kala Shah Kaku in 2010 during kharif season to study the influence of nitrogen (N) and potash (K) on severity of Bacterial leaf blight (BLB) of rice (Oryza sativa L.) aimed at improving productivity. The experiment was laid out in randomized complete block design with factorial arrangement with three replications. Treatments comprised of: 0 kg N ha-1, 75 kg N ha-1, 100 kg N ha-1, 125 kg N ha-1 and 0 kg K ha-1, 50 kg K ha-1, 75 kg K ha-1, 100 kg K ha-1. Data on disease severity and paddy yield were recorded using standard procedures. Paddy yield was affected significantly by various combinations of N & K. In case of bacterial leaf blight, minimum diseased incidence percentage was observed when nitrogen alone was applied @ 75 kg·ha-1 in contrast to fertilizer applied @ 125 kg N ha-1 + 50 kg K ha-1 which showed maximum diseased incidence percentage. Maximum paddy yield (4.32 t·ha-1 ) was recorded when rice was fertilized @ 75 kg N ha-1 + 100 kg K ha-1 as compared to sole fertilization of 75 kg K ha-1 that produced minimum paddy yield (2.40 t·ha-1). Maximum gross income, net returns and benefit cost ratio were obtained where rice crop was fertilized @ 75 kg N ha-1 and 100 kg K ha-1.
