Antioxidation responses of maize roots and leaves to partial root-zone irrigation

Antioxidation responses of maize roots and leaves to water deficit and rewatering under partial root-zone irrigation (PRI) were investigated using a pot system. Plants were cultured using three irrigation methods, i.e. conventional irrigation (CI), alternate PRI (APRI) and fixed PRI (FPRI) with three different water regimes including W₁ (70% field capacity, FC), W₂ (50% FC) and W₃ (35% FC). Compared to CI, root peroxidases (POD) activity was enhanced in the irrigated root zone of FPRI and both root zones of APRI during mild water deficit. After rewatering, POD activity was increased in the dry root zone under FPRI but reduced in the roots under APRI. Roots in the dry zone and leaves under FPRI remained high superoxide dismutase (SOD) activity after rewatering. In contrast, SOD activity decreased in the roots and leaves under CI and APRI. Malondialdehyde (MDA) contents were increased in leaves and two sub-roots under FPRI during water deficit and remained higher after rewatering compared to those under CI and APRI. MDA contents in the tissues under APRI showed similar levels to those under CI. Compared to CI, APRI showed the same biomass production, achieving significantly higher water use efficiency under mild water deficit. The results suggested that plants under APRI experienced less oxidative stress or damage induced by water deficit.     

Fuzzy multi-objective linear programming applying to crop area planning

Crop area planning plays significant role in agricultural water management. During the planning, because of ambiguous or uncertain information caused by the vagueness of decision makers’ subjective preference or the uncertainty of objective information, conventional multi-objective linear programming (MOLP) model is not suitable for such decision-making in such fuzzy environment. In this study, we proposed the fuzzy multi-objective linear programming (FMOLP) model with triangular fuzzy numbers and transformed the FMOLP model and its corresponding fuzzy goal programming (FGP) problem to crisp ones which can be solved by the conventional programming methods. The FMOLP model was applied to crop area planning of Liang Zhou region, Gansu province of northwest China, and then the optimal cropping patterns under different water-saving levels and satisfaction grades for water resources availability of the decision makers (DM) were obtained. Compared to the MOLP model, the FMOLP model itself expresses the fuzzy information effectively, and its solutions can represent the DMs satisfactory degree of the subjective preference and propose alternative solutions for better decision support when applied in the crop area planning.     

Water-use efficiency and physiological responses of maize under partial root-zone irrigation

Alternate partial root-zone irrigation (APRI) is a water-saving irrigation method but also can regulate crop physiological responses. This study investigated how water-use efficiency (WUE) and other physiological responses were regulated at different growth stages when maize plants were applied with APRI and how these responses were recovered to control levels when full irrigation was resumed. A pot experiment was carried out at two fertilization levels and with three irrigation methods at the jointing stage (29-38 days after sowing) or during the jointing and tasselling stages (29-77 days after sowing). The irrigation methods included the conventional irrigation (CI), APRI and fixed PRI (FPRI, watering was fixed to one side). Compared to the CI, APRI at the jointing stage for 10 days or during the jointing and tasselling stages for 49 days reduced water consumption by 10.6-12.9 and 31.7-32.4%, respectively, but did not reduce total dry mass accumulation significantly, thus increased canopy WUE by 10.4-13.6 and 41.2-41.8%, respectively. FPRI reduced the total dry mass significantly even though it also improved canopy WUE. APRI had slight effect on the leaf relative water content (RWC), chlorophyll (Chl), carotenoid (CAR), proline (Pro) and malondialdehyde (MDA) contents and superoxide dismutase (SOD) and peroxidase (POD) activities from jointing to tasselling stages but recovery to the levels of CI was rapid after receiving full watering. In comparison, FPRI treatment significantly reduced leaf RWC, Chl and CAR contents and SOD and POD activities and increased the Pro and MAD contents. After receiving full watering, the above-mentioned physiological indexes in FPRI could not recover fully to the levels of CI. High fertilization treatment only increased leaf Chl content significantly and contributed little to the total dry mass accumulation. Our result suggests that APRI can make plants use water and nutrients more efficiently with better drought tolerance.     

甘蔗近缘野生种蔗茅EfGRAS基因克隆及表达分析

为深入挖掘甘蔗品种的抗旱性能,本研究挑选甘蔗品种中参与调控抗旱机制的主要转录因子GRAS的基因进行表达分析。从转录组数据库中调取GRAS转录因子基因序列信息,采用RACE-PCR和qRT-PCR技术从‘蔗茅99-2’中克隆得到1个GRAS基因,将其命名为EfGRAS（GenBank登录号MT499789）,并对其进行生物信息学分析与干旱胁迫表达分析。结果表明,EfGRAS基因编码547个氨基酸,CDS全长1644 bp,该蛋白的分子式为C₂₆₄₅H₄₁₄₉N₇₄₇O₈₁₆S₂₁,相对分子质量为60.14 kDa,不稳定系数为54.85,脂肪系数为84.37,GRAVY值为?0.293,是一类不稳定蛋白和亲水蛋白;亚细胞定位表明其位于细胞核内,EfGRAS蛋白主要的二级结构是α-螺旋和无规则卷曲,与高粱亲缘关系最近;qRT-PCR分析显示,受到干旱胁迫后,‘蔗茅99-2’中基因表达量相比于对照组上调约57.6倍,‘滇蔗01-58’中基因表达量相比于对照上调约27.4倍,‘崖城89-9’中基因表达量相比于对照组上调倍数较低。本研究结果为进一步研究EfGRAS基因在甘蔗中的功能提供理论基础。     

厚皮毛竹纤维形态研究

首次报道了江西特产毛竹栽培变型－厚皮毛竹的秆杆纤维长度,宽度,长宽比,纤维含量和维管束密度的变化规律,并与毛竹同类指标进行了比较,结果表明各项指标的变化规律与毛竹相同。引种后的厚皮毛 影响其利用价值方面的指标 生不良的变化。     

Simulation of artificial neural network model for trunk sap flow of Pyrus pyrifolia and its comparison with multiple-linear regression

Trunk sap flow of tree is an important index in the irrigation decision of orchard. On the basis of the measured sap flow (SF) of pear tree (Pyrus pyrifolia) in the field, the multiple-linear regression for simulating the SF was obtained after analyzing the relationships between the SF and its affecting factors in this study and an artificial neural network (ANN) technique was applied to construct a nonlinear mapping to simulate the SF, then the simulated SF by two models was, respectively, compared to the measured value. Results showed that trunk SF had significant relationship with the vapour pressure deficit (VPD) in the single-variable analysis method but with soil volumetric water content (θ) using the ANN models with default of different variables. The correlation coefficient (R²), mean relative error (MRE) and root mean square error (RMSE) between the measured and simulated sap flows by the ANN model developed by taking VPD, solar radiation (S_r), air temperature (T), wind speed (W_s), θ, leaf area index (LAI) as the input variables were 0.953, 10.0% and 5.33 L d⁻¹, respectively, and the simulation precision of ANN model was superior to that of multiple-linear regression due to its better performance for the nonlinear relationship between trunk SF and its affecting factors, thus ANN model can simulate trunk sap flow and then may help the efficient water management of orchard.     

Response of vegetative growth and fruit development to regulated deficit irrigation at different growth stages of pear-jujube tree

In order to investigate the response of vegetative growth, fruit development and water use efficiency to regulated deficit irrigation at different growth stages of pear-jujube tree (Zizyphus jujube Mill.), different water deficit at single-stage were treated on field grown 7-year old pear-jujube trees in 2005 and 2006. Treatments included severe (SD), moderate (MD) and low (LD) water deficit treatments at bud-burst to leafing (I), flowering to fruit set (II), fruit growth (III) and fruit maturation (IV) stages. Compared to the full irrigation (control), different water deficit treatments at different growth stages reduced photosynthesis rate (P_n) slightly and transpiration rate (T_r) significantly, thus it improved leaf water use efficiency (WUE_L, defined as the ratio of P_n to T_r) by 2.7-26.1%. After the re-watering, P_n had significant compensatory effect, but T_r was not enhanced significantly, thus WUE_L was improved by 31.4-42.2%. I-SD, I-MD, II-SD and II-MD decreased new shoot length, new shoot diameter and panicle length by 8-28%, 13-23% and 10-31%, respectively. Simultaneously, they reduced leaf area index (LAI) and pruning amount significantly. Flowering of pear-jujube tree advanced by 3-8 days in the water deficit treatments at stage I, Furthermore, SD and MD at stage I increased flowers per panicle and final fruit set by 18.9-40.5% and 15.5-36.6%, respectively. After a period of re-watering, different water deficit treatments at different growth stages improved the fruit growth rate by 15-30% without reduction of the final fruit volume. Compared to the control, I-MD, I-SD, I-LD, I-MD and I-SD treatments increased fruit yield by 13.2-31.9%, but reduced water consumption by 9.7-17.5%, therefore, they enhanced water use efficiency at yield level (WUE_Y, defined as ratio of fruit yield to total water use) by 17.3-41.4%. Therefore, suitable period and degree of water deficit can reduce irrigation water and restrain growth redundancy significantly, and it optimize the relationship between vegetative growth and reproductive growth of pear-jujube trees, which maintained or slightly increased the fruit yield, thus water use efficiency was significantly increased.     

Pb-LEX-HPLC分析秸秆糖化液中葡萄糖和木糖含量

建立了秸秆糖化液中两种单糖的铅配位体交换高效液相色谱分析方法。分离柱采用Sepax Carbomix Pb-NP10(300×7.8 mmID,10μm,8%交联度)色谱柱,柱温80℃;流动相采用乙腈/水=5/95(v/v),流速0.60 mL·min-1;示差折光检测器温度35℃;样品采用自制活性炭固相萃取装置处理。葡萄糖和木糖25 min内完成分离,在0.2~10.0 mg·mL-1浓度范围内呈现良好的线性关系,方法检测限分别为0.094 mg·mL-1和0.098 mg·mL-1。方法样品前处理简便,重现性好,结果准确。     

亚热带次生混交林中不同类群植物叶片可提取态碳水化合物的分配格局

可提取态碳水化合物(EC)是植物光合作用的主要产物,能较好地反映植物的适应性和竞争力,目前对不同类群植物间的异同及其在适应与竞争机制方面的解释尚不明确。研究在亚热带地区马尾松林演替至常绿阔叶林中间阶段的次生混交林中选取17种常绿植物和13种落叶植物,于生长旺季和叶凋落期分别收集鲜叶和凋落叶,采用连续浸提7步分级法测定7类EC的含量,比较分析不同类型植物叶片EC的变化规律。结果表明,(1)常绿植物鲜叶游离态糖类的含量及百分比分别为52 mg/g和54%,均高于落叶植物的48.11 mg/g和49%,而水溶性半纤维素类相反(P0.05);其它几种EC差异均不显著。(2)常绿植物凋落叶的游离态糖类、弱结合态糖类、强结合态糖类和水溶性半纤维素类占有机碳比例分别为10.82%、2.87%、2.70%和3.44%,均低于落叶植物的13.14%、3.95%、3.81%和4.51%;乔木凋落叶游离态糖类和弱结合态糖类占有机碳比例则为10.73%和2.78%,低于灌木的11.90%和3.40%及草藤本的11.98%和3.40%。(3)常绿植物鲜叶的游离态糖类和弱结合态糖类含量显著高于其凋落叶;而落叶植物鲜叶的游离态糖类和总EC含量则明显低于其凋落叶。推断与落叶植物竞争时,常绿植物可能通过提高鲜叶的游离态糖类含量,增强叶片碳源利用取得优势。     

3种泥鳅微卫星标记和D-Loop部分序列遗传变异分析

为进一步了解中国当前主要养殖鳅类种质资源现状,实验采用7个微卫星标记和线粒体D-Loop部分序列,对泥鳅(Misgurnus anguillicaudatus,MA)、大鳞副泥鳅(Paramisgurnus dabryanus,PD)和台湾大泥鳅(未见种属分类,TW)3种泥鳅进行群体遗传变异分析.结果显示,6个微卫星位点在3种泥鳅中均能获得有效扩增,1个微卫星标记(Mac239)只在MA中获得特异性扩增,而在PD和TW中未能获得有效扩增条带.在3种泥鳅共90尾个体的D-Loop 部分序列中发现32个单倍型,仅在PD和TW间存在1个共享单倍型.实验中共检测到65个变异位点,其中MA与PD和TW间存在29个特异性位点,而PD和TW间未检测到特异性位点.瓶颈效应和中性检验显示,TW近期可能发生有效群体数量的减少.基于微卫星标记和D-Loop部分序列的遗传变异分析显示,TW和PD间的Nei's遗传距离和K2P遗传距离最近(0.297和0.006),明显小于两者与MA间的遗传距离(1.011～1.899和0.095～0.099);分子方差分析(AMOVA)显示,3种泥鳅的遗传分化极显著(P＜0.01).群体间遗传结构和单倍型网络分析显示,3种泥鳅的遗传结构相对独立,仅在TW和PD间存在一定程度的遗传结构混杂.研究表明,泥鳅和大鳞副泥鳅在遗传结构上存在明显差异,可采用分子标记进行有效鉴别;台湾大泥鳅可能是大鳞副泥鳅的生态种群或遗传改良群体,而非有效物种.