The culm of the Triticum aestivum L. cv. “Lankao 906_4”, a high_yield cultivar, in comparison with “Jing 411”, a widely_planted cultivar, was studied by means of anatomical technique coupled with mechanical an...The culm of the Triticum aestivum L. cv. “Lankao 906_4”, a high_yield cultivar, in comparison with “Jing 411”, a widely_planted cultivar, was studied by means of anatomical technique coupled with mechanical and chemical theory. A anatomical analysis revealed that “Lankao 906_4” possessed thicker mechanical tissue and larger vascular bundle area than those of “Jing 411”. In terms of the resistance to lodging, “Lankao 906_4” had higher culm strength. Furthermore the content of lignin was semiquantitatively analyzed with confocal laser scanning mircoscope (CLSM), and revealed a much higher lignin content in the culm of “Lankao 906_4” than that in the culm of “Jing 411”. All of these indicated that the characteristics of culm were important factors in breeding the super_production wheat cultivar.展开更多
Rice culm carbohydrate transport can simultaneously affect grain filling and stem lodging resistance by regulating non-structural carbohydrate(NSC) and structural carbohydrate(SC) contents. However, the relationship b...Rice culm carbohydrate transport can simultaneously affect grain filling and stem lodging resistance by regulating non-structural carbohydrate(NSC) and structural carbohydrate(SC) contents. However, the relationship between carbohydrate transposition and culm strength is not well documented. Accordingly, a high-yielding hybrid rice cultivar(Y Liangyou 2) was tested under different N fertilization regimes at two locations, Taoyuan(a special high-yield eco-site), Yunnan province and Danyang(a representative eco-site of the middle and lower Yangtze), Jiangsu province, China. Significantly higher grain yield and basal stem strength were found at Taoyuan than Danyang under all N rates throughout the two-year experiment. At heading stage, soluble sugars, starch, cellulose and lignin contents of the basal culm at Taoyuan were significantly 132.0%, 73.7%, 1.2%, and 62.7% higher than those at Danyang, respectively. At 20 days after heading, soluble sugars and starch content at Taoyuan decreased significantly compared to Danyang, but lignin content remained higher. Culm carbohydrate transport to kernels at Taoyuan was significantly greater than that at Danyang, and the proportion of soluble sugars and starch was correspondingly 62.9%lower. However, the proportion of lignin and cellulose was 22.7% higher at Taoyuan than that at Danyang. Soluble sugars and starch partitioning were significantly reduced under an increased nitrogen application rate, but SC partitioning was little affected. There were significant positive correlations between basal culm bending stress and dry weight and cellulose and lignin proportions at both locations under all N rates, suggesting that the higher SC proportion at 20 days after heading was primarily responsible for culm strength.These results suggest that high-yielding rice populations with greater culm strength require both moderate NSC transport and greater SC accumulation.展开更多
We investigated the culm form for one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houz. in relation to the me- chanical constraint principles, i.e., elastic, stress and geometric similarity. The fi...We investigated the culm form for one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houz. in relation to the me- chanical constraint principles, i.e., elastic, stress and geometric similarity. The fine-resolution analysis of the culm taper indicated that the culm for P. pubescens consisted of three or four segments with various forms, except for the butt swell. This implied that the taper of the whole culm for P. pubescens could be expressed by neither of these principles. The regression slope between culm height and diameter at breast height on the double logarithmic coordinates was 0.629, which was significantly different from the values predicted from these principles. In conclusion, none of these mechanical constraint principles can express the culm taper and height-diameter relationship, and there may be a need for a more complicated model to express the culm form for P. pubescens.展开更多
Because plant mechanical strength influences plant growth and development,the regulatory mechanisms underlying cell-wall synthesis deserve investigation.Rice mutants are useful for such research.We have identified a n...Because plant mechanical strength influences plant growth and development,the regulatory mechanisms underlying cell-wall synthesis deserve investigation.Rice mutants are useful for such research.We have identified a novel brittle culm 25(bc25)mutant with reduced growth and partial sterility.BC25 encodes an UDP-glucuronic acid decarboxylase involved in cellulose synthesis and belongs to the UXS family.A single-nucleotide mutation in BC25 accounts for its altered cell morphology and cellwall composition.Transmission electron microscopy analysis showed that the thickness of the secondary cell wall was reduced in bc25.Monosaccharide analysis revealed significant increases in content of rhamnose and arabinose but not of other monosaccharides,indicating that BC25 was involved in xylose synthesis with some level of functional redundancy.Enzymatic assays suggested that BC25 functions with high activity to interconvert UDP-glucuronic acid(UDP-Glc A)and UDP-xylose.GUS staining showed that BC25 was ubiquitously expressed with higher expression in culm,root and sheath,in agreement with that shown by quantitative real-time(q RT)-PCR.RNA-seq further suggested that BC25 is involved in sugar metabolism.We conclude that BC25 strongly influences rice cell wall formation.展开更多
We investigated the influence of season on the rooting be- haviour of eight important bamboo species viz., Bambusa balcooa, B. bambos, B. nutans, B. tuMa, B. vulgaris, Dendrocalamus giganteus, D. hamiltonii and D. str...We investigated the influence of season on the rooting be- haviour of eight important bamboo species viz., Bambusa balcooa, B. bambos, B. nutans, B. tuMa, B. vulgaris, Dendrocalamus giganteus, D. hamiltonii and D. strictus. We collected 2-3 node culm cuttings in three growing seasons viz. spring （March）, summer （June） and rainy （August） from superior candidate plus clumps （CPCs） centralized in the germplasm garden. Cuttings were placed horizontally in sand and were provided with intermittent misting at regular intervals. Bamboo species exhibited differential rhizogenesis behavior in different seasons. The study reveals significant variation in sprouting and rooting behaviour in different bamboo species. B. bambos had maximum rooting （78.89%）, followed by B. vulgaris （74.44%）. In general, the potential of different bamboo species for rooting was found to be in the order： B. bambos 〉 B. vulgaris 〉 B. balcooa 〉 D. hamiltonii 〉 B. tulda 〉 D. strictus 〉 D. giganteus 〉B. nutans. The maximum rooting was recorded in spring （56.67%）, which was closely followed by summer （54.58%）. In winter season, minimum rooting （36.67%） was observed. The interaction effect of species x season was also significant on sprouting and rooting pa- rameters. In B. balcooa, B. nutans, B. vulgaris, D. hamiltonii and D. strictus, cuttings collected in summer season showed maximum sprouting and rooting, whereas, B. bambos, B. tulda and D. giganteus had maximum rooting in spring. The maximum number of roots developed per cutting was observed in B. tulda （43.8） during spring season.展开更多
Cadmium （Cd） accumulation and toxicity in rice plants were characterized and identified by using brittle culm 1 （bcl）, a fragile rice mutant and its wild type （Shuangkezao, an indica rice） as materials by hydrop...Cadmium （Cd） accumulation and toxicity in rice plants were characterized and identified by using brittle culm 1 （bcl）, a fragile rice mutant and its wild type （Shuangkezao, an indica rice） as materials by hydroponics. The low Cd level didn＇t obviously affect the growth parameters in both rice genotypes, but under high Cd levels （1.0 and 5.0 μmol/L）, the growth of both rice plants were substantially inhibited. Moreover, bcl tended to suffer more seriously from Cd toxicity than Shuangkezao. Cd accumulation in both rice plants increased with the increase of Cd levels. There was a significant difference in Cd accumulation between the two rice genotypes with constantly higher Cd concentration in bcl, which also accumulated more Cd at 0, 0.1, and 1.0 μmol/L Cd levels. The same case was found in the two rice plants grown on Cd-contaminated soil. This suggested that cell wall might play an important role in Cd accumulation in rice plants by the physiological mechanisms. The malondialdehyde （MDA） content, superoxide dismutase （SOD） and peroxidase （POD） activities in rice plants were affected differently under Cd treatments, and which implied that POD might play the main role in detoxifying active oxygen free radical. A significant difference in antioxidative system between the two rice genotypes was found with constantly higher MDA content, SOD and POD activities in bcl. In summary, bcl accumulated more Cd and appeared to be more sensitive to Cd stress compared with its wild type.展开更多
The hollow cylindrical culm is one of the most remarkable morphological characters of most bamboo species.In relation to its hollow structure,there are two different attributes of the culm volume in bamboo:the apparen...The hollow cylindrical culm is one of the most remarkable morphological characters of most bamboo species.In relation to its hollow structure,there are two different attributes of the culm volume in bamboo:the apparent culm volume(va:the total culm volume including the hollow portion)and the woody culm volume(vw:the volume of the woody walls of the culm).The ratio of vw to va is defined as the reduction factor for culm volume(fv).The quantity fv is useful to quantify the biomass resources of bamboo culms as well as to evaluate the carbon stock of bamboo forests.However,the direct measurement of fv requires destructive sampling,which consumes time and labor.Hence,an alternative method for obtaining fv is desired.In this study,we examined fv in five species of the genus Phyllostachys and proposed alternative methods to estimate fv.Our data showed that fv varied by species,some of which exhibited a dependency of fv on culm sizes.These findings indicate that the intraspecific and interspecific variation in fv should be considered carefully when converting va into vw by fv.Based on our results,we propose here six approaches for predicting fv and we discuss their advantages and disadvantages.Our results are intended to facilitate evaluation of the carbon sequestration capacity of bamboo forests and the commercial utilization of bamboo culms.展开更多
Leaf nitrogen resorption is very important to Phyllostachys edulis development because the withdrawn nitrogen can help newly emerging and growing culms.However, few studies have focused on the ontogenetic changes in l...Leaf nitrogen resorption is very important to Phyllostachys edulis development because the withdrawn nitrogen can help newly emerging and growing culms.However, few studies have focused on the ontogenetic changes in leaf nitrogen resorption of P. edulis. Here, we examined the variability in mature leaf nitrogen concentrations(Nm), nitrogen resorption efficiency(NRE) and proficiency(NRP or Ns) and leaf-level nitrogen use efficiency(NUE) of the current-, 3 rd-and 5 th-year culms in P.edulis stands under extensive management. Analyses of variance and correlation indicated that patterns of Nm,NRP, NRE and NUE were markedly affected by culm age and leaf nitrogen status. Nm, Nsand NRE were significant higher in younger(current-year) culms with 1-year lifespan leaves, while NUE was markedly higher in older(3 rd-or 5 th-year) culms with 2-year lifespan leaves. Significant linear correlations between Nmand NRP, NRE and NUE,Nmand NUE, Nsand NRE were found for each culm age,and Nmwas significantly positively correlated to NRE for all culms pooled. Higher proficiency in older culms led to higher NUE and lower NRE, these relationships can be modulated by Nm, which in turn, is restrained by leaf N availability and acquisition. Our results revealed that at the intraspecific level, P. edulis can adjust its leaf NRE, NRP,and leaf-level NUE in concert with culm development.Understanding nitrogen resorption characteristics and NUE of P. edulis can help decision-makers design appropriate deforestation strategies and achieve precise N fertilization for sustainable bamboo forest management.展开更多
We used thermal images of bamboo culms of Guadua angustifolia Kunth to analyze the relationship between culm surface temperature and maturity, driven by the hypothesis that young culms may exhibit lower surface temper...We used thermal images of bamboo culms of Guadua angustifolia Kunth to analyze the relationship between culm surface temperature and maturity, driven by the hypothesis that young culms may exhibit lower surface temperatures than old ones. The culm surface temperature shows small but constant differences between three age classes of 1, 2, and 3 years. Our findings indicate that surface temperature may be applied as an additional indi- cator to support the determination of maturity of guadua culms besides the visual assessment of the culms.展开更多
Due to their interesting properties, bamboo fibers are more and more used as reinforcements in polymer matrices as a substitute for synthetic fibers. For their future service life, it is important to understand their ...Due to their interesting properties, bamboo fibers are more and more used as reinforcements in polymer matrices as a substitute for synthetic fibers. For their future service life, it is important to understand their physical and mechanical behavior over time in order to control the aging phenomenon within this fiber. The paper analyzed the influence of the age of the bamboo thatch and the vertical position of the Bambusa vulgaris species cultivated in Cameroon on the physicomechanical properties of the fibers extracted from the thatch. Fibers were mechanically extracted from three bamboo culms aged respectively 3 years (BV3), 4 years (BV4) and 5 years (BV5). The culms were thus identified according to their number of ramifications, and were felled no abated for a total of three culms. A section of about one meter on each of the parts (lower part, middle part, upper part) of these three culms was made for the opposite technological studies. Each age was therefore represented by three portions of thatch, one from the upper part, one from the middle part and the last from the lower part of the thatch, all giving a total number of nine samples taken and marked BV3inf, BV3moy, BV3sup, BV4inf, BV4moy, BV4sup, BV5inf, BV5moy, BV5sup before handling in the laboratory. Physical (density, moisture absorption rate) and mechanical (tensile tests according to DIN EN ISO 13934-1, natural durability) characterizations were used to better understand the mechanisms of this influence. In view of all the results obtained, the fiber from the upper part of the 3-year-old thatch (BV3sup) is the one with the best characteristics and is recommended for a better elaboration of bamboo fiber composites: (Density: 0.83;Absorption rate 11.7%;Young’s modulus: 7.4 GPa;Maximal stress: 64.3 MPa;Elongation at rupture: 1.1;Loss of mass natural durability: 7.63%).展开更多
Bamboo is one of the fastest growing and highest yielding renewable resources with multiple uses in the world. Lack of seedlings in sufficient number has generally been a major constraint in establishing more bamboo p...Bamboo is one of the fastest growing and highest yielding renewable resources with multiple uses in the world. Lack of seedlings in sufficient number has generally been a major constraint in establishing more bamboo plantations. This study investigated the efficiency of regenerating Bambusa vulgaris through cuttings at Busogo sector, Musanze district, using vertical and horizontal methods with and without water treatment. The experiment consisted in a RCBD （Randomized Complete Block Design） with 4 replications. The growth and sprouting of the 64 cuttings were monitored for three months and 18 days （105 days）. In terms of planting method, horizontal planting method showed best sprouting percentage of 68%. In terms of treatment used, horizontal planting method without using water treatment showed slightly better sprouting percentage of 60%. The results further show that about 87% of sprouts had between 0 and 30 cm height and 98% of sprouts had basal diameter ranging from 0 to 20 mm only 105 days after planting. Indeed, the horizontal planting methods provided highest survival rate of sprouts than the vertical planting method （74%） of planted cuttings. Furthermore, the results show that, 105 days after planting, cuttings with horizontal method were more productive in terms of root development. In terms of planting method using water treatment, the horizontal planting method with water treatment showed highest rooting percentage （44%）. Therefore, farmers should be trained and encouraged to use horizontal planting method using water treatment in order to get better results in regenerating bamboo through cuttings.展开更多
Dwindling supplies of bamboo resources and the increase in the demand for bamboo ha</span></span><span><span><span style="font-family:"">ve</span></span></sp...Dwindling supplies of bamboo resources and the increase in the demand for bamboo ha</span></span><span><span><span style="font-family:"">ve</span></span></span><span><span><span style="font-family:""> led to the need for better propagation techniques. This is the only way to ensure the sustainability of the bamboo resource base and improve livelihoods. Thus, this study was carried out to examine the different growth parameters of culm cuttings of <i>Bambusa vulgaris</i> in propagation beds with a substrate consisting of dark soil, manure (compost) and sand in a ratio of 1:1:1. Data on different growth parameters was collected on a daily basis over a three week period and analyzed using appropriate descriptive and inferential statistics. It was found that the different growth parameters (diameter, height, leaves and sheaths) of culm cuttings of <i>B. vulgaris</i> evolved in like manner in three propagation beds. Descriptive statistics for growth parameters of culm cuttings of <i>B. vulgaris</i> showed little or no differences across three shelter/propagation beds (shelter bed 1, shelter bed 2 and shelter bed 3) with 1.4675 ± 1.6172 cm, 93 ± 112 cm, 22 ± 30 leaves, and 4 ± 6 sheaths being the mean diameter, height, number of leaves and number of sheaths for all three propagation beds, respectively. ANOVA test showed no statistically significant variation (<i>p</i> > 0.05) between growth parameters of culm cuttings of <i>B. vulgaris</i> across the three propagation beds, implying that the different growth parameters were relatively similar. Pearson correlation showed the existence of direct and inverse relationships between the different growth parameters of culm cuttings of bamboo. The existence of these direct and inverse relationships could be attributed to the rapid growth rate of bamboo, the substrate used, and the species of bamboo used (<i>B. vulgaris</i>). The study recommends more large-scale propagation projects of this bamboo species in order to ensure the sustainability of the bamboo resource base and improve livelihoods of bamboo dependent rural communities.展开更多
Rapid growth is an innovative trait of woody bamboos that has been widely studied.However,the genetic basis and evolution of this trait are poorly understood.Taking advantage of genomic resources of 11 representative ...Rapid growth is an innovative trait of woody bamboos that has been widely studied.However,the genetic basis and evolution of this trait are poorly understood.Taking advantage of genomic resources of 11 representative bamboos at different ploidal levels,we integrated morphological,physiological,and transcriptomic datasets to investigate rapid growth.In particular,these bamboos include two large-sized and a small-sized woody species,compared with a diploid herbaceous species.Our results showed that gibberellin A1 was important for the rapid shoot growth of the world's largest bamboo,Dendrocalamus sinicus,and indicated that two gibberellins(GAs)-related genes,KAO and SLRL1,were key to the rapid shoot growth and culm size in woody bamboos.The expression of GAs-related genes exhibited significant subgenome asymmetry with subgenomes A and C demonstrating expression dominance in the large-sized woody bamboos while the generally submissive subgenomes B and D dominating in the small-sized species.The subgenome asymmetry was found to be correlated with the subgenome-specific gene structure,particularly UTRs and core promoters.Our study provides novel insights into the molecular mechanism and evolution of rapid shoot growth following allopolyploidization in woody bamboos,particularly via subgenome asymmetry.These findings are helpful for understanding of how polyploidization in general and subgenome asymmetry in particular contributed to the origin of innovative traits in plants.展开更多
This study characterizes a brittle culm (bc88) mutant of rice (Oryza sativa L.) obtained by ethylene methylsulfonate (EMS)-induced mutagenesis of Wuyunjing 7. The bc88 mutant exhibits a diversity of pleiotropic phenot...This study characterizes a brittle culm (bc88) mutant of rice (Oryza sativa L.) obtained by ethylene methylsulfonate (EMS)-induced mutagenesis of Wuyunjing 7. The bc88 mutant exhibits a diversity of pleiotropic phenotypes, including brittle culm at the whole-plant growth stages, withered leaf tips at the seedling stage, and 18-d delay in heading date at the mature stage. Genetic analysis indicates that the bc88 mutant is controlled by a single recessive nuclear gene. The mutated bc88 gene isolated by map-based cloning contains only one point mutation in the 5th exon relative to its wild-type BC88 (LOC_Os09g25490 and Os09g0422500), leading to an amino acid change from P to L in bc88 plants. Alignment of the putative protein sequence with its homologs indicates that the mutation is located in the conserved region of the sequence. Detection of the transcription level of BC88 in rice plants shows that the expression level of BC88 is higher in spikes and culms than in leaves, roots, and leaf sheaths. These contribute to understanding of the molecular mechanism of cellulose synthesis. The target gene BC88 can be a useful tool in molecular marker-assisted selection for rice culm trait breeding.展开更多
【目的】通过探究花叶矢竹体细胞无性系变异株系茎秆形态、解剖结构及细胞壁组分等特征的动态变化,揭示花叶矢竹茎秆倒伏的生理机制。【方法】以发生体细胞无性系变异的花叶矢竹矮化倒伏突变体(dwarf and lodging mutant,DWF)为研究对象...【目的】通过探究花叶矢竹体细胞无性系变异株系茎秆形态、解剖结构及细胞壁组分等特征的动态变化,揭示花叶矢竹茎秆倒伏的生理机制。【方法】以发生体细胞无性系变异的花叶矢竹矮化倒伏突变体(dwarf and lodging mutant,DWF)为研究对象,以正常组织培养的花叶矢竹(WT)为对照,同时移栽90、180、270、和360天后,分别调查其新生竹秆的表型、横切面解剖结构、细胞壁组分含量的变化。【结果】DWF在不同移栽时期中茎秆形态、解剖结构、细胞壁组分含量与WT差异显著。1)相较于WT,DWF茎秆在4个移栽时期中均发生不同程度的倒伏,移栽90天时茎秆与地面夹角为35.27°,茎秆倒伏程度最大,移栽360天时茎秆与地面夹角为73.13°,茎秆倒伏程度最小。2)DWF茎秆直径、茎秆高度、基部节间长度极显著低于WT,移栽360天时差异最大;DWF生长缓慢,移栽270~360天时,DWF新生茎秆高度增幅仅为WT的21.41%,新生茎秆直径增幅只有WT的17.49%。3)DWF大小维管束数量及面积均极显著低于WT,移栽360天时DWF大维管束数量及面积分别比WT低65.71%及55.35%,小维管束数量及面积分别比WT低75.44%及55.51%,WT新生茎秆大小维管束数量及面积快速增长时,DWF增幅缓慢;DWF厚壁组织厚度变薄,在4个时期中与WT均存在极显著差异,分别比WT低50.21%、55.77%、54.59%、45.41%;DWF髓腔发育缓慢,移栽270天与360天时出现髓腔,髓腔直径极显著低于WT。4)随着移栽时间的延长,DWF新生茎秆的木质素、纤维素含量增加,但极显著低于WT,且半纤维素含量无显著差异,节间木质素及纤维素沉积程度也低于WT。5)DWF茎秆倒伏程度与其茎秆直径存在显著负相关关系,与大小维管束数量及面积、厚壁组织厚度、木质素及纤维素含量存在极显著负相关关系。【结论】相较于花叶矢竹WT,DWF在发育过程中,茎秆高度增长滞缓和呈现矮化,茎秆强度弱和发生倒伏。DWF茎秆直径小、大小维管束的数量少和面积小、厚壁组织厚度低,是其发生倒伏的一个重要原因;DWF细胞壁的木质素及纤维素含量低,造成其茎秆强度弱,是其发生倒伏的另一原因。展开更多
In the present study, In order to systematically dissect the genetic mechanism of rice （Oryza satlva L.） tilling for the super rice ideotype and the model system of branching development, two ethyl methane suifonate...In the present study, In order to systematically dissect the genetic mechanism of rice （Oryza satlva L.） tilling for the super rice ideotype and the model system of branching development, two ethyl methane suifonate-induced rice reduced-culm-number（rcn） mutants from the progeny of Nippobare （O. satlva ssp. japonica）, namely rcn8 and rcn9, were used. Their maximum tillers were both less than 4. in addition, rcn9 had another major feature of rust-spotted leaves. Allelic tests between these two mutants and seven other recessive few-tiller mutants revealed that they were previously unknown loci. Genetic analysis showed that the rcn traits were all controlled by a pair of different recessive genes, designated as RCN8and RCNg, respectively. Two F2 populations derived from crosses between the rcn8 or rcn9 mutants and 93-11 were constructed. Linkage analysis using two rcn F2 mapping populations with published simple sequence repeat markers demonstrated that the RCN8 and RCN9 genes were mapped on the long arm of chromosome 1 （119.6 cM） and the short arm of chromosome 6 （63.6 cM）, respectively. The results of the present study are beneficial to map-based cloning and functional analysis of the RCN8 and RCN9 genes.展开更多
基金The State Key Basic Research and Development Plan(G1998010100)
文摘The culm of the Triticum aestivum L. cv. “Lankao 906_4”, a high_yield cultivar, in comparison with “Jing 411”, a widely_planted cultivar, was studied by means of anatomical technique coupled with mechanical and chemical theory. A anatomical analysis revealed that “Lankao 906_4” possessed thicker mechanical tissue and larger vascular bundle area than those of “Jing 411”. In terms of the resistance to lodging, “Lankao 906_4” had higher culm strength. Furthermore the content of lignin was semiquantitatively analyzed with confocal laser scanning mircoscope (CLSM), and revealed a much higher lignin content in the culm of “Lankao 906_4” than that in the culm of “Jing 411”. All of these indicated that the characteristics of culm were important factors in breeding the super_production wheat cultivar.
基金supported by the National Natural Science Foundation of China (31501268)National Key Research and Development Program of China (2016YFD0300501)+1 种基金National Key Technology R&D Program of China (2015BAC02B02)the Agricultural Science and Technology Innovation Program of CAAS (Y2016PT12, Y2016XT01)
文摘Rice culm carbohydrate transport can simultaneously affect grain filling and stem lodging resistance by regulating non-structural carbohydrate(NSC) and structural carbohydrate(SC) contents. However, the relationship between carbohydrate transposition and culm strength is not well documented. Accordingly, a high-yielding hybrid rice cultivar(Y Liangyou 2) was tested under different N fertilization regimes at two locations, Taoyuan(a special high-yield eco-site), Yunnan province and Danyang(a representative eco-site of the middle and lower Yangtze), Jiangsu province, China. Significantly higher grain yield and basal stem strength were found at Taoyuan than Danyang under all N rates throughout the two-year experiment. At heading stage, soluble sugars, starch, cellulose and lignin contents of the basal culm at Taoyuan were significantly 132.0%, 73.7%, 1.2%, and 62.7% higher than those at Danyang, respectively. At 20 days after heading, soluble sugars and starch content at Taoyuan decreased significantly compared to Danyang, but lignin content remained higher. Culm carbohydrate transport to kernels at Taoyuan was significantly greater than that at Danyang, and the proportion of soluble sugars and starch was correspondingly 62.9%lower. However, the proportion of lignin and cellulose was 22.7% higher at Taoyuan than that at Danyang. Soluble sugars and starch partitioning were significantly reduced under an increased nitrogen application rate, but SC partitioning was little affected. There were significant positive correlations between basal culm bending stress and dry weight and cellulose and lignin proportions at both locations under all N rates, suggesting that the higher SC proportion at 20 days after heading was primarily responsible for culm strength.These results suggest that high-yielding rice populations with greater culm strength require both moderate NSC transport and greater SC accumulation.
基金supported in part by the Sumitomo Foundation (Grant no. 083062)
文摘We investigated the culm form for one of the largest bamboo species, Phyllostachys pubescens Mazel ex Houz. in relation to the me- chanical constraint principles, i.e., elastic, stress and geometric similarity. The fine-resolution analysis of the culm taper indicated that the culm for P. pubescens consisted of three or four segments with various forms, except for the butt swell. This implied that the taper of the whole culm for P. pubescens could be expressed by neither of these principles. The regression slope between culm height and diameter at breast height on the double logarithmic coordinates was 0.629, which was significantly different from the values predicted from these principles. In conclusion, none of these mechanical constraint principles can express the culm taper and height-diameter relationship, and there may be a need for a more complicated model to express the culm form for P. pubescens.
基金supported by the Key Research and Development Program of Zhejiang Province(2021C02056,2021C02063-6)the National Key Research and Development Program of China(2021YFD1200503)+1 种基金the Fundamental Research Funds for Central Public Welfare Research Institutes of China National Rice Research Institute(CPSIBRF-CNRRI-202101)Chinese Academy of Agricultural Sciences(CAAS-ASTIP-201X-CNRRI)。
文摘Because plant mechanical strength influences plant growth and development,the regulatory mechanisms underlying cell-wall synthesis deserve investigation.Rice mutants are useful for such research.We have identified a novel brittle culm 25(bc25)mutant with reduced growth and partial sterility.BC25 encodes an UDP-glucuronic acid decarboxylase involved in cellulose synthesis and belongs to the UXS family.A single-nucleotide mutation in BC25 accounts for its altered cell morphology and cellwall composition.Transmission electron microscopy analysis showed that the thickness of the secondary cell wall was reduced in bc25.Monosaccharide analysis revealed significant increases in content of rhamnose and arabinose but not of other monosaccharides,indicating that BC25 was involved in xylose synthesis with some level of functional redundancy.Enzymatic assays suggested that BC25 functions with high activity to interconvert UDP-glucuronic acid(UDP-Glc A)and UDP-xylose.GUS staining showed that BC25 was ubiquitously expressed with higher expression in culm,root and sheath,in agreement with that shown by quantitative real-time(q RT)-PCR.RNA-seq further suggested that BC25 is involved in sugar metabolism.We conclude that BC25 strongly influences rice cell wall formation.
基金supported by National Mission on Bamboo Applications (NMBA),Department of Science & Technology,New Delhi, India
文摘We investigated the influence of season on the rooting be- haviour of eight important bamboo species viz., Bambusa balcooa, B. bambos, B. nutans, B. tuMa, B. vulgaris, Dendrocalamus giganteus, D. hamiltonii and D. strictus. We collected 2-3 node culm cuttings in three growing seasons viz. spring （March）, summer （June） and rainy （August） from superior candidate plus clumps （CPCs） centralized in the germplasm garden. Cuttings were placed horizontally in sand and were provided with intermittent misting at regular intervals. Bamboo species exhibited differential rhizogenesis behavior in different seasons. The study reveals significant variation in sprouting and rooting behaviour in different bamboo species. B. bambos had maximum rooting （78.89%）, followed by B. vulgaris （74.44%）. In general, the potential of different bamboo species for rooting was found to be in the order： B. bambos 〉 B. vulgaris 〉 B. balcooa 〉 D. hamiltonii 〉 B. tulda 〉 D. strictus 〉 D. giganteus 〉B. nutans. The maximum rooting was recorded in spring （56.67%）, which was closely followed by summer （54.58%）. In winter season, minimum rooting （36.67%） was observed. The interaction effect of species x season was also significant on sprouting and rooting pa- rameters. In B. balcooa, B. nutans, B. vulgaris, D. hamiltonii and D. strictus, cuttings collected in summer season showed maximum sprouting and rooting, whereas, B. bambos, B. tulda and D. giganteus had maximum rooting in spring. The maximum number of roots developed per cutting was observed in B. tulda （43.8） during spring season.
文摘Cadmium （Cd） accumulation and toxicity in rice plants were characterized and identified by using brittle culm 1 （bcl）, a fragile rice mutant and its wild type （Shuangkezao, an indica rice） as materials by hydroponics. The low Cd level didn＇t obviously affect the growth parameters in both rice genotypes, but under high Cd levels （1.0 and 5.0 μmol/L）, the growth of both rice plants were substantially inhibited. Moreover, bcl tended to suffer more seriously from Cd toxicity than Shuangkezao. Cd accumulation in both rice plants increased with the increase of Cd levels. There was a significant difference in Cd accumulation between the two rice genotypes with constantly higher Cd concentration in bcl, which also accumulated more Cd at 0, 0.1, and 1.0 μmol/L Cd levels. The same case was found in the two rice plants grown on Cd-contaminated soil. This suggested that cell wall might play an important role in Cd accumulation in rice plants by the physiological mechanisms. The malondialdehyde （MDA） content, superoxide dismutase （SOD） and peroxidase （POD） activities in rice plants were affected differently under Cd treatments, and which implied that POD might play the main role in detoxifying active oxygen free radical. A significant difference in antioxidative system between the two rice genotypes was found with constantly higher MDA content, SOD and POD activities in bcl. In summary, bcl accumulated more Cd and appeared to be more sensitive to Cd stress compared with its wild type.
基金supported by JSPS KAKENHI(Grant Numbers:15KK0220,JP16K12823,JP16K14948,25390147,18H03818,18H02244 and 18KT0027)
文摘The hollow cylindrical culm is one of the most remarkable morphological characters of most bamboo species.In relation to its hollow structure,there are two different attributes of the culm volume in bamboo:the apparent culm volume(va:the total culm volume including the hollow portion)and the woody culm volume(vw:the volume of the woody walls of the culm).The ratio of vw to va is defined as the reduction factor for culm volume(fv).The quantity fv is useful to quantify the biomass resources of bamboo culms as well as to evaluate the carbon stock of bamboo forests.However,the direct measurement of fv requires destructive sampling,which consumes time and labor.Hence,an alternative method for obtaining fv is desired.In this study,we examined fv in five species of the genus Phyllostachys and proposed alternative methods to estimate fv.Our data showed that fv varied by species,some of which exhibited a dependency of fv on culm sizes.These findings indicate that the intraspecific and interspecific variation in fv should be considered carefully when converting va into vw by fv.Based on our results,we propose here six approaches for predicting fv and we discuss their advantages and disadvantages.Our results are intended to facilitate evaluation of the carbon sequestration capacity of bamboo forests and the commercial utilization of bamboo culms.
基金supported by the Key Project of National Key Research and Development Plans(2016YFC0500204)the Chinese National Basic Research Program(2013BAC03B05)+1 种基金the Key Project for the Strategic Science Plan in Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences(No.2012ZD007)State Forestry Administration project948(2014-4-58)
文摘Leaf nitrogen resorption is very important to Phyllostachys edulis development because the withdrawn nitrogen can help newly emerging and growing culms.However, few studies have focused on the ontogenetic changes in leaf nitrogen resorption of P. edulis. Here, we examined the variability in mature leaf nitrogen concentrations(Nm), nitrogen resorption efficiency(NRE) and proficiency(NRP or Ns) and leaf-level nitrogen use efficiency(NUE) of the current-, 3 rd-and 5 th-year culms in P.edulis stands under extensive management. Analyses of variance and correlation indicated that patterns of Nm,NRP, NRE and NUE were markedly affected by culm age and leaf nitrogen status. Nm, Nsand NRE were significant higher in younger(current-year) culms with 1-year lifespan leaves, while NUE was markedly higher in older(3 rd-or 5 th-year) culms with 2-year lifespan leaves. Significant linear correlations between Nmand NRP, NRE and NUE,Nmand NUE, Nsand NRE were found for each culm age,and Nmwas significantly positively correlated to NRE for all culms pooled. Higher proficiency in older culms led to higher NUE and lower NRE, these relationships can be modulated by Nm, which in turn, is restrained by leaf N availability and acquisition. Our results revealed that at the intraspecific level, P. edulis can adjust its leaf NRE, NRP,and leaf-level NUE in concert with culm development.Understanding nitrogen resorption characteristics and NUE of P. edulis can help decision-makers design appropriate deforestation strategies and achieve precise N fertilization for sustainable bamboo forest management.
基金both financially supported by‘‘Nuevas metodologías para la evaluación y monitoreo de carbono e indicadores de biodiversidad en sistemas silvopastoriles y bosques de guadua en paisajes de la zona cafetera de Colombia’’‘‘Innovación tecnológica para la optimización de procesos y la estandarización de productos en empresas rurales con base en Guadua:una contribución para el fortalecimiento de la competitividad de la cadena productiva de la Guadua en el eje cafetero de Colombia’’by Colciencias
文摘We used thermal images of bamboo culms of Guadua angustifolia Kunth to analyze the relationship between culm surface temperature and maturity, driven by the hypothesis that young culms may exhibit lower surface temperatures than old ones. The culm surface temperature shows small but constant differences between three age classes of 1, 2, and 3 years. Our findings indicate that surface temperature may be applied as an additional indi- cator to support the determination of maturity of guadua culms besides the visual assessment of the culms.
文摘Due to their interesting properties, bamboo fibers are more and more used as reinforcements in polymer matrices as a substitute for synthetic fibers. For their future service life, it is important to understand their physical and mechanical behavior over time in order to control the aging phenomenon within this fiber. The paper analyzed the influence of the age of the bamboo thatch and the vertical position of the Bambusa vulgaris species cultivated in Cameroon on the physicomechanical properties of the fibers extracted from the thatch. Fibers were mechanically extracted from three bamboo culms aged respectively 3 years (BV3), 4 years (BV4) and 5 years (BV5). The culms were thus identified according to their number of ramifications, and were felled no abated for a total of three culms. A section of about one meter on each of the parts (lower part, middle part, upper part) of these three culms was made for the opposite technological studies. Each age was therefore represented by three portions of thatch, one from the upper part, one from the middle part and the last from the lower part of the thatch, all giving a total number of nine samples taken and marked BV3inf, BV3moy, BV3sup, BV4inf, BV4moy, BV4sup, BV5inf, BV5moy, BV5sup before handling in the laboratory. Physical (density, moisture absorption rate) and mechanical (tensile tests according to DIN EN ISO 13934-1, natural durability) characterizations were used to better understand the mechanisms of this influence. In view of all the results obtained, the fiber from the upper part of the 3-year-old thatch (BV3sup) is the one with the best characteristics and is recommended for a better elaboration of bamboo fiber composites: (Density: 0.83;Absorption rate 11.7%;Young’s modulus: 7.4 GPa;Maximal stress: 64.3 MPa;Elongation at rupture: 1.1;Loss of mass natural durability: 7.63%).
文摘Bamboo is one of the fastest growing and highest yielding renewable resources with multiple uses in the world. Lack of seedlings in sufficient number has generally been a major constraint in establishing more bamboo plantations. This study investigated the efficiency of regenerating Bambusa vulgaris through cuttings at Busogo sector, Musanze district, using vertical and horizontal methods with and without water treatment. The experiment consisted in a RCBD （Randomized Complete Block Design） with 4 replications. The growth and sprouting of the 64 cuttings were monitored for three months and 18 days （105 days）. In terms of planting method, horizontal planting method showed best sprouting percentage of 68%. In terms of treatment used, horizontal planting method without using water treatment showed slightly better sprouting percentage of 60%. The results further show that about 87% of sprouts had between 0 and 30 cm height and 98% of sprouts had basal diameter ranging from 0 to 20 mm only 105 days after planting. Indeed, the horizontal planting methods provided highest survival rate of sprouts than the vertical planting method （74%） of planted cuttings. Furthermore, the results show that, 105 days after planting, cuttings with horizontal method were more productive in terms of root development. In terms of planting method using water treatment, the horizontal planting method with water treatment showed highest rooting percentage （44%）. Therefore, farmers should be trained and encouraged to use horizontal planting method using water treatment in order to get better results in regenerating bamboo through cuttings.
文摘Dwindling supplies of bamboo resources and the increase in the demand for bamboo ha</span></span><span><span><span style="font-family:"">ve</span></span></span><span><span><span style="font-family:""> led to the need for better propagation techniques. This is the only way to ensure the sustainability of the bamboo resource base and improve livelihoods. Thus, this study was carried out to examine the different growth parameters of culm cuttings of <i>Bambusa vulgaris</i> in propagation beds with a substrate consisting of dark soil, manure (compost) and sand in a ratio of 1:1:1. Data on different growth parameters was collected on a daily basis over a three week period and analyzed using appropriate descriptive and inferential statistics. It was found that the different growth parameters (diameter, height, leaves and sheaths) of culm cuttings of <i>B. vulgaris</i> evolved in like manner in three propagation beds. Descriptive statistics for growth parameters of culm cuttings of <i>B. vulgaris</i> showed little or no differences across three shelter/propagation beds (shelter bed 1, shelter bed 2 and shelter bed 3) with 1.4675 ± 1.6172 cm, 93 ± 112 cm, 22 ± 30 leaves, and 4 ± 6 sheaths being the mean diameter, height, number of leaves and number of sheaths for all three propagation beds, respectively. ANOVA test showed no statistically significant variation (<i>p</i> > 0.05) between growth parameters of culm cuttings of <i>B. vulgaris</i> across the three propagation beds, implying that the different growth parameters were relatively similar. Pearson correlation showed the existence of direct and inverse relationships between the different growth parameters of culm cuttings of bamboo. The existence of these direct and inverse relationships could be attributed to the rapid growth rate of bamboo, the substrate used, and the species of bamboo used (<i>B. vulgaris</i>). The study recommends more large-scale propagation projects of this bamboo species in order to ensure the sustainability of the bamboo resource base and improve livelihoods of bamboo dependent rural communities.
基金supported by the Key Project of Natural Science Foundation of Yunnan Province (202401AS070082)the National Natural Science Foundation of China (grants 32120103003 and 31970355)
文摘Rapid growth is an innovative trait of woody bamboos that has been widely studied.However,the genetic basis and evolution of this trait are poorly understood.Taking advantage of genomic resources of 11 representative bamboos at different ploidal levels,we integrated morphological,physiological,and transcriptomic datasets to investigate rapid growth.In particular,these bamboos include two large-sized and a small-sized woody species,compared with a diploid herbaceous species.Our results showed that gibberellin A1 was important for the rapid shoot growth of the world's largest bamboo,Dendrocalamus sinicus,and indicated that two gibberellins(GAs)-related genes,KAO and SLRL1,were key to the rapid shoot growth and culm size in woody bamboos.The expression of GAs-related genes exhibited significant subgenome asymmetry with subgenomes A and C demonstrating expression dominance in the large-sized woody bamboos while the generally submissive subgenomes B and D dominating in the small-sized species.The subgenome asymmetry was found to be correlated with the subgenome-specific gene structure,particularly UTRs and core promoters.Our study provides novel insights into the molecular mechanism and evolution of rapid shoot growth following allopolyploidization in woody bamboos,particularly via subgenome asymmetry.These findings are helpful for understanding of how polyploidization in general and subgenome asymmetry in particular contributed to the origin of innovative traits in plants.
基金supported by the National Natural Science Foundation of China (30971760, 31201183)the Zhejiang Provincial Qianjiang Talents Program of China ( 2010R10085)the Zhejiang Program of Education Department (Y201225687)
文摘This study characterizes a brittle culm (bc88) mutant of rice (Oryza sativa L.) obtained by ethylene methylsulfonate (EMS)-induced mutagenesis of Wuyunjing 7. The bc88 mutant exhibits a diversity of pleiotropic phenotypes, including brittle culm at the whole-plant growth stages, withered leaf tips at the seedling stage, and 18-d delay in heading date at the mature stage. Genetic analysis indicates that the bc88 mutant is controlled by a single recessive nuclear gene. The mutated bc88 gene isolated by map-based cloning contains only one point mutation in the 5th exon relative to its wild-type BC88 (LOC_Os09g25490 and Os09g0422500), leading to an amino acid change from P to L in bc88 plants. Alignment of the putative protein sequence with its homologs indicates that the mutation is located in the conserved region of the sequence. Detection of the transcription level of BC88 in rice plants shows that the expression level of BC88 is higher in spikes and culms than in leaves, roots, and leaf sheaths. These contribute to understanding of the molecular mechanism of cellulose synthesis. The target gene BC88 can be a useful tool in molecular marker-assisted selection for rice culm trait breeding.
文摘【目的】通过探究花叶矢竹体细胞无性系变异株系茎秆形态、解剖结构及细胞壁组分等特征的动态变化,揭示花叶矢竹茎秆倒伏的生理机制。【方法】以发生体细胞无性系变异的花叶矢竹矮化倒伏突变体(dwarf and lodging mutant,DWF)为研究对象,以正常组织培养的花叶矢竹(WT)为对照,同时移栽90、180、270、和360天后,分别调查其新生竹秆的表型、横切面解剖结构、细胞壁组分含量的变化。【结果】DWF在不同移栽时期中茎秆形态、解剖结构、细胞壁组分含量与WT差异显著。1)相较于WT,DWF茎秆在4个移栽时期中均发生不同程度的倒伏,移栽90天时茎秆与地面夹角为35.27°,茎秆倒伏程度最大,移栽360天时茎秆与地面夹角为73.13°,茎秆倒伏程度最小。2)DWF茎秆直径、茎秆高度、基部节间长度极显著低于WT,移栽360天时差异最大;DWF生长缓慢,移栽270~360天时,DWF新生茎秆高度增幅仅为WT的21.41%,新生茎秆直径增幅只有WT的17.49%。3)DWF大小维管束数量及面积均极显著低于WT,移栽360天时DWF大维管束数量及面积分别比WT低65.71%及55.35%,小维管束数量及面积分别比WT低75.44%及55.51%,WT新生茎秆大小维管束数量及面积快速增长时,DWF增幅缓慢;DWF厚壁组织厚度变薄,在4个时期中与WT均存在极显著差异,分别比WT低50.21%、55.77%、54.59%、45.41%;DWF髓腔发育缓慢,移栽270天与360天时出现髓腔,髓腔直径极显著低于WT。4)随着移栽时间的延长,DWF新生茎秆的木质素、纤维素含量增加,但极显著低于WT,且半纤维素含量无显著差异,节间木质素及纤维素沉积程度也低于WT。5)DWF茎秆倒伏程度与其茎秆直径存在显著负相关关系,与大小维管束数量及面积、厚壁组织厚度、木质素及纤维素含量存在极显著负相关关系。【结论】相较于花叶矢竹WT,DWF在发育过程中,茎秆高度增长滞缓和呈现矮化,茎秆强度弱和发生倒伏。DWF茎秆直径小、大小维管束的数量少和面积小、厚壁组织厚度低,是其发生倒伏的一个重要原因;DWF细胞壁的木质素及纤维素含量低,造成其茎秆强度弱,是其发生倒伏的另一原因。
基金Supported by the Hi-Tech Research and Development （863） Program of China （2002AA221003） and the National Natural Science Foundation of China （30425034）.
文摘In the present study, In order to systematically dissect the genetic mechanism of rice （Oryza satlva L.） tilling for the super rice ideotype and the model system of branching development, two ethyl methane suifonate-induced rice reduced-culm-number（rcn） mutants from the progeny of Nippobare （O. satlva ssp. japonica）, namely rcn8 and rcn9, were used. Their maximum tillers were both less than 4. in addition, rcn9 had another major feature of rust-spotted leaves. Allelic tests between these two mutants and seven other recessive few-tiller mutants revealed that they were previously unknown loci. Genetic analysis showed that the rcn traits were all controlled by a pair of different recessive genes, designated as RCN8and RCNg, respectively. Two F2 populations derived from crosses between the rcn8 or rcn9 mutants and 93-11 were constructed. Linkage analysis using two rcn F2 mapping populations with published simple sequence repeat markers demonstrated that the RCN8 and RCN9 genes were mapped on the long arm of chromosome 1 （119.6 cM） and the short arm of chromosome 6 （63.6 cM）, respectively. The results of the present study are beneficial to map-based cloning and functional analysis of the RCN8 and RCN9 genes.
