本文分析了近年来气候变化特点及对我国油菜生态环境及油菜生产的影响。结果表明，随着气温升高，冬油菜潜在种植面积显著增加，传统的油菜生产格局发生改变，体现出明显的“东减、北移、西扩”特征；由于降水分布不均、极端气候事件频繁，油菜单产增加趋势减缓，油菜生产的不稳定性显著增加。根据当前油菜生产所面临的问题，提出了整合育种和栽培措施的应对策略。

本文在分析了我国食用植物油供给形势、油菜产业在食用植物油供给中的地位的基础上，对我国油菜产业的发展历史进行了回顾，提出在新的历史时期必须推动以“三高”（“高油、高产、高效”）为标志的我国油菜产业发展的第四次飞跃来应对新的挑战。

Leaf growth is one of the first physiological processes affected by changes in plant water status under drought. A decrease in leaf expansion rate usually precedes any reduction in stomatal conductance or photosynthesis. Changes in leaf size and stomatal opening are potential adaptive mechanisms, which may help avoid drought by reducing transpiration rate, and can be used to improve rice genotypes in water-saving cultivation. The indica rice cultivar IR64 and four of its near-isogenic lines (NILs; BC(3)-derived lines) unique for leaf size traits, YTK 124 (long leaves), YTK 127 (broad leaves), YTK 205 (short leaves) and YTK 214 (narrow leaves), were compared in this study for changes in leaf growth and its water status. The plants were subjected to two soil water regimes, well-watered and progressive soil drying measured by the fraction of transpirable soil water (FTSW). Applied drought reduced leaf number, total leaf area, specific leaf area, plant biomass, tiller number, plant height, stomatal conductance, amount of water transpired, leaf relative water content, and leaf water potential more in IR64 and the NILs than in the respective controls; nonetheless, transpiration efficiency (TE) was slightly higher under drought than in the well-watered controls. NILs with broader leaves had higher biomass (and its individual components), less stomatal conductance, and higher TE under drought than NILs with narrow and shorter leaves. Under drought, leaf number was positively correlated with tiller number and plant height; nonetheless, root weight and total biomass, water transpired and TE, and plant height and TE were positively correlated with each other. However, a negative correlation was observed between stomatal conductance and the FTSW threshold at which normalized transpiration started to decline during soil drying. Overall, the IR64-derived lines with broader leaves performed better than NILs with narrow and short leaves under drought.Copyright 2010 Elsevier GmbH. All rights reserved.

Understanding the complex interactions of competition, climate warming-induced drought stress, and photosynthetic productivity on the radial growth of trees is central to linking climate change impacts on tree growth, stand structure and in general, forest productivity. Using a mixed modeling approach, a stand-level photosynthetic production model, climate, stand competition and tree-ring data from mixedwood stands in western Canada, we investigated the radial growth response of white spruce [Piceaglauca (Moench.) Voss] to simulated annual photosynthetic production, simulated drought stress, and tree and stand level competition. The long-term (similar to 80-year) radial growth of white spruce was constrained mostly by competition, as measured by total basal area, withminor effects fromdrought. There was no relation of competition and drought on tree growth but dominant trees increased their growth more strongly to increases in modeled photosynthetic productivity, indicating asymmetric competition. Our results indicate a co-limitation of drought and climatic factors inhibiting photosynthetic productivity for radial growth of white spruce in western Canada. These results illustrate how a modeling approach can separate the complex factors regulating both multi-decadal average radial growth and interannual radial growth variations of white spruce, and contribute to advance our understanding on sustainable management of mixedwood boreal forests in western Canada.

采用砂培法，利用14%（m/V）聚乙二醇（PEG-6000）模拟干旱胁迫，研究39份甘蓝型油菜发芽期根系性状的变化及其与抗旱性的关系。结果表明，干旱胁迫对油菜根鲜重和侧根数有明显的抑制作用，而对根长和根冠比的影响较小。相关分析表明，相对侧根数与活力指数之间以及根长与活力指数之间均呈显著正相关，可作为抗旱性鉴定的辅助指标。杂交种和常规种在根系性状上差别不显著，表明其抗旱能力相当。对油菜的抗旱性进行综合评价和聚类分析发现，在欧式距离为60时39份材料可分为5个类群，其中A类抗旱性最强，平均相对侧根数77.9%，相对根长98.9%；E类抗旱性最差，平均相对侧根数69.3%，相对根长84.5%。筛选出发芽期抗旱性较强的3份材料：OR918、OR805和OR2025。 

【目的】研究大麦半矮秆基因uzu与抗旱性的关系，为大麦抗旱优质育种提供理论依据。【方法】以两套大麦株高近等基因系(3T、3D和15T、15D)为试验材料，采用营养液水培方式，以不同浓度的PEG6000模拟干旱胁迫，研究不同胁迫程度：对照（0）、轻度（5%）、中度（15%）和重度胁迫（25%）对大麦株高近等基因系幼苗株高、根冠比、根系形态及叶片渗透调节物质的影响。在幼苗长至四叶一心时取样，直尺测定株高；采用烘干称重法获得根系生物量和地上部生物量，二者比值乘以100%得到根冠比；利用根系扫描仪对样根进行扫描测量，并用WinRHIZO软件进行单株总根长、根表面积和根体积的分析；可溶性糖含量用硫酸-蒽酮比色法测定；可溶性蛋白含量用考马斯亮蓝G-250染色法测定；脯氨酸含量用酸性茚三酮显色法测定。【结果】随着PEG6000浓度的增加，大麦幼苗生长受到明显抑制，株高逐渐降低，而根冠比则呈相反的变化趋势。就根系形态而言，随胁迫程度的增加，两套近等基因系表现出不同的变化趋势，在轻度和中度胁迫下3D和15T的变化幅度分别小于3T和15D，在重度胁迫下则表现相反。可溶性糖含量随胁迫浓度的增加呈先升高后降低再升高的变化趋势，而可溶性蛋白含量变化趋势与可溶性糖含量相反；在轻度和中度胁迫下3D和15D的变化幅度分别小于3T和15T，在重度胁迫下也表现相反。但脯氨酸含量随胁迫浓度升高呈现上升趋势，且在不同胁迫浓度下均表现为3D和15D变化幅度较小。相关分析表明：不同胁迫处理下，除可溶性蛋白含量外，株高与其他性状均存在显著相关关系；根冠比与根系形态以及根系形态之间也存在显著相关关系。同时，具有较高可溶性糖含量的品系其脯氨酸含量也较高，而可溶性蛋白含量则较低。此外，根系形态与叶片渗透调节物质之间亦存在一定的相关性，即总根长和根表面积均与可溶性糖含量和脯氨酸含量呈现显著负相关关系。【结论】在根系形态及叶片渗透调节方面，大麦株高近等基因系对苗期不同干旱胁迫的响应存在差异并相互影响。在轻度和中度胁迫程度下，近等基因系3T和3D中半矮秆基因的存在有利于抵御干旱胁迫。

【目的】研究干旱胁迫对不同抗旱性苜蓿品种根系生长特征及生理特性的影响，明确不同抗旱性苜蓿品种响应干旱胁迫的生长及生理差异，为进一步阐明紫花苜蓿抗旱的分子机理、提高紫花苜蓿耐旱性和水分利用效率提供理论依据。【方法】采用营养液沙培法，选用强抗旱的陇中苜蓿（Medicago sativa L. cv. Longzhong）、中抗旱的陇东苜蓿（Medicago sativa L. cv. Longdong）和弱抗旱的甘农3号紫花苜蓿（Medicago sativa L. cv. Gannong No.3）为试验材料，在幼苗期对其进行6种不同水势（0、-0.4、-0.8、-1.2、-1.6和-2.0 MPa）的PEG-6000人工模拟干旱胁迫，研究干旱胁迫对供试苜蓿根系生长特征（根系总长度、根系总表面积、根系平均直径、根体积、根尖数和根系干重）、根系活力、游离脯氨酸（Pro）含量、可溶性蛋白（SP）含量、可溶性糖（SS）含量，丙二醛（MDA）含量、质膜相对透性、活性氧（H₂O₂、OH·和O₂^•-）含量，抗氧化酶（SOD、POD和CAT）活性、还原型抗坏血酸（AsA）和还原型谷胱甘肽（GSH）含量的影响。并用逐步回归分析建立最优回归方程，进而筛选出不同胁迫程度下对不同抗旱性苜蓿品种抗旱性影响较为显著的指标。【结果】干旱胁迫会显著影响苜蓿的根系生长特征及生理特性。随着干旱胁迫的加剧，供试苜蓿的根系总长度、Pro含量、MDA含量、质膜相对透性、活性氧（H₂O₂、OH·和O₂^•-）含量及CAT活性不断增加；根系干重、根系活力、SS含量和GSH含量先增加后下降。此外，随胁迫程度增加，陇中苜蓿的根系平均直径、根体积、根尖数、POD活性及SOD活性均呈先增加后下降的变化趋势，AsA含量不断增加；陇东苜蓿和甘农3号的根系平均直径、根体积、根尖数、POD活性及根系总表面积则呈不断下降的趋势，而AsA含量呈先增加后下降的变化趋势。整体而言，陇中苜蓿的根系总长度、根系总表面积、根系干重显著高于陇东苜蓿和甘农3号，H₂O₂含量和O₂^•-含量显著低于甘农3号；陇中苜蓿和陇东苜蓿的SP含量、SS含量和MDA含量显著低于甘农3号。-1.2 MPa至-2.0 MPa胁迫时，陇中苜蓿的H₂O₂和OH·含量显著低于陇东苜蓿。-2.0 MPa胁迫时，陇中苜蓿的POD活性、AsA和GSH含量均显著高于甘农3号。逐步回归分析表明，根系活力、根体积、根系总长度、MDA和AsA是对陇中苜蓿抗旱性影响较为显著的指标；根尖数、根系平均直径、根系总表面积、根系干重、O₂^•-、GSH和CAT是对陇东苜蓿抗旱性影响较为显著的指标；根系活力、根尖数、Pro、SS、MDA、质膜相对透性和GSH是对甘农3号紫花苜蓿抗旱性影响较为显著的指标。【结论】不同抗旱性苜蓿品种在形态特征和生理特性上对干旱胁迫存在相同和不同的生长及生理响应策略。轻度和中度胁迫（0 MPa至-1.2 MPa）下，抗旱苜蓿品种主要通过增加根系总长度、根体积和根尖数及降低膜脂过氧化程度来适应干旱，弱抗旱苜蓿品种则通过改变细胞膜稳定性、根系活力及渗透调节能力来适应干旱；重度胁迫（-1.2 MPa至-2.0 MPa）下，不同抗旱性苜蓿品种均可通过改变根系生长特征和启动抗氧化系统来抵御干旱，其中强抗旱苜蓿品种主要通过增加根长和AsA含量来适应干旱，而中等抗旱和弱抗旱苜蓿品种主要通过增加根尖数和GSH含量来适应干旱。

Effects of cadmium (Cd(2+)) on photosynthetic and antioxidant activities of maize (Zea mays L.) cultivars (3223 and 32D99) were investigated. Fourteen-day-old cultivar seedlings were exposed to different Cd concentrations [0, 0.3, 0.6 and 0.9mM Cd(NO(3))(2) x 4H(2)O] for 8 days. The results of chlorophyll fluorescence indicated that different levels of Cd affected photochemical efficiency in 3223 much more than that in 32D99. In parallel, the level of Cd at 0.9mM caused oxidative damage but did not indicate cessation of PSII activity of the cultivars; plant death was not observed at highly toxic Cd levels. Additionally, the increase in Cd concentration caused loss of chlorophylls and carotenoid and membrane damage in both cultivars, but greater membrane damage was observed in 3223 than in 32D99. Depending on Cd accumulation, a significant reduction in dry biomass was observed in both cultivars at all Cd concentrations. The accumulation of Cd was higher in roots than in leaves for both cultivars. Nevertheless, cultivar 3223 transferred more Cd from roots to leaves than did 32D99. On the other hand, our results suggest that there were similar responses in SOD, APX and GR activities with increasing Cd concentrations for both cultivars. However, POD activity significantly increased at highly toxic Cd levels in 32D99. This result may be regarded as an indication of better tolerance of the Z. mays L. cultivar 32D99 to Cd contamination.