Comment on "Changes in climatic water balance drive downhill shifts in plant species' optimum elevations"

Crimmins et al. (Reports, 21 January 2011, p. 324) presented a study that purports to show that plants in California are shifting downslope to maintain a constant water deficit. We argue that the results are limited in scope to just a handful of woody species in one part of the state and are confounded by methodological errors.     

Maize grain yield and water use efficiency in relation to climatic factors and plant population in northern China

Water scarcity has become a limiting factor for increasing crop production. Finding ways to improve water use efficiency (WUE) has become an urgent task for Chinese agriculture. To understand the response of different maize populations to changes in precipitation and the effects of changes in maize populations on WUE, this study conducted maize population experiments using maize hybrids with different plant types (compact and semi compact) and different planting densities at 25 locations across China. It was found that, as precipitation increased across different locations, maize grain yield first increased and then decreased, while WUE decreased significantly. Analyzing the relationship between WUE and the main climatic factors, this study found that WUE was significantly and negatively correlated with precipitation ($$ (daily mean precipitation) and R (accumulated precipitation)) and was positively correlated with temperature (T_M (daily mean maximum temperature), T_M–m (T_m, daily mean minimum temperature) and GDD (growing degree days)) and solar radiation ($$ (daily mean solar radiation) and Ra (accumulated solar radiation)) over different growth periods. Significant differences in maize grain yield, WUE and precipitation were found at different planting densities. The population densities were ranked as follows according to maize grain yield and WUE based on the multi-site experiment data: 60 000 plants ha^–1 (P₂)>90 000 plants ha^–1 (P₃)>30 000 plants ha^–1 (P₁). Further analysis showed that, as maize population increased, water consumption increased significantly while soil evaporation decreased significantly. Significant differences were found between the WUE of ZD958 (compact type) and that of LD981 (semi-compact type), as well as among the WUE values at different planting densities. In addition, choosing the optimum hybrid and planting density increased WUE by 21.70 and 14.92%, respectively, which showed that the hybrid played a more significant role than the planting density in improving WUE. Therefore, choosing drought-resistant hybrids could be more effective than increasing the planting density to increase maize grain yield and WUE in northern China. Comprehensive consideration of climatic impacts, drought-resistant hybrids (e.g., ZD958) and planting density (e.g., 60 000 plants ha^–1) is an effective way to increase maize grain yield and WUE across different regions of China.     

淡水白鲳饲料中适宜动植物蛋白比例的研究

以常规饲料为原料,用豆粕等植物蛋白分别替代16%、28%、40%、52%、64%、76%、88%和100%的鱼粉蛋白,配制成8组等蛋白水平(粗蛋白质为30%左右)、等能(总能为39 kJ/g)的饲料,对体长为(5.66±0.09)cm、体重(3.16±0.16)g的淡水白鲳Colussoma brachypomum进行45 d的生长试验。结果表明:当饲料中用植物蛋白替代鱼粉蛋白的比例为28%、40%、52%、64%时,淡水白鲳的特定生长率分别为2.73、2.79、2.65、2.67%/d,其间差异不显著(P>0.05),但显著高于其余各组(P<0.05);各处理组之间的饲料系数、蛋白质效率的差异与特定生长率相似;淡水白鲳饲料中适宜的动植物蛋白比为1∶1.67。     

不同海拔高寒森林凋落物分解过程中土壤微生物群落的变化

为探究高寒森林凋落物分解过程中土壤微生物群落结构的变化,揭示海拔对土壤微生物群落和凋落物分解的影响,本研究于西藏色季拉山3 500～4 300 m海拔梯度开展为期一年的凋落物掩埋实验,结合微生物群落结构变化和不同海拔凋落物降解规律来分析,阐明土壤理化性质、微生物群落结构和凋落物分解的响应关系。结果表明：不同海拔土壤细菌群落组成相对稳定,优势菌门丰度受总氮、碳氮比显著影响（P<0.05）;土壤含水率、碳氮比显著影响真菌优势菌门变化（P<0.05）;细菌和真菌群落的α-多样性指数均受海拔、凋落物降解及二者交互作用的显著影响（P<0.001）。高海拔（4 100和4 300 m）和低海拔（3 500、3 700和3 900 m）土壤微生物群落结构分别具有一定相似性,而不同海拔细菌和真菌共生网络复杂程度差异较大;掩埋1年后,凋落物在不同海拔的降解率为28.2%～45.2%,碳氮比与凋落物降解率呈显著负相关关系（P<0.05）。研究发现,海拔、碳氮比、土壤含水率均对细菌、真菌群落演替和凋落物降解率产生直接或间接的影响,真菌群落较细菌群落对凋落物降解贡献更大。本研究可为色季...     

Abnormal water balance in a mutant strain of chickens

Polydipsia and polyuria are pronounced in chickens of a selected strain and this diabetes insipidus is inherited. The kidneys of such birds are capable of an antidiuretic response when lysine vasopressin or arginine vasotocin is injected. Osmotic pressure and sodium concentration of the plasmas of normal and mutant chickens are identical. Chicks predicted to have diabetes insipidus on the basis of parental pedigree are polydipsic.     

防御和减轻气象灾害: 2006年世界气象日主题

\t\t\t\t\t目的\t\t\t\t\t研究全球气候变化背景条件下佳木斯市旱涝灾害演变规律。\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t以1951年以来佳木斯市春季逐日降水资料及国家气候中心74项环流指数实时资料为依据,用降水距平百分率R_i和Z指数法分析佳木斯市春季旱涝类型、出现频率及时空分布特点并建立春季降水预报方程。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t1961—2015年,佳木斯市所属县(市)出现大涝和大旱的频率在72%~96%,1996年以前出现大旱频率较高,而1996年以后出现大涝的概率更大;佳木斯市在年降水量减少的同时,春季3—5月降水变化呈上升趋势,在55年的线性变化趋势中,每10年增加约9.6%;从地域分布看,佳木斯西部地区比东部更易发生旱涝且转换更加频繁;佳木斯春季旱涝趋势主要受前一年春冬季大气环流的影响,以Minitab 16筛选的环流特征量为因子,建立春季降水量预报方程,其预测春季旱涝类型准确率为63.6%。\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t研究结果可为佳木斯市春季旱涝灾害的短期气候预测提供参考依据。\t\t\t\t     

A significant upward shift in plant species optimum elevation during the 20th century

Spatial fingerprints of climate change on biotic communities are usually associated with changes in the distribution of species at their latitudinal or altitudinal extremes. By comparing the altitudinal distribution of 171 forest plant species between 1905 and 1985 and 1986 and 2005 along the entire elevation range (0 to 2600 meters above sea level) in west Europe, we show that climate warming has resulted in a significant upward shift in species optimum elevation averaging 29 meters per decade. The shift is larger for species restricted to mountain habitats and for grassy species, which are characterized by faster population turnover. Our study shows that climate change affects the spatial core of the distributional range of plant species, in addition to their distributional margins, as previously reported.     

爪哇白豆蔻在海南扩种栽培的气候适应性分析

根据爪哇白豆蔻的生物学特性,应用农业气候相似性原理,采用模糊优先选择比方法,对爪哇白豆蔻在海南扩种栽培的适应性进行分析,结果表明,海南万宁、琼海、昌江、保亭、屯昌、定安和文昌等地区为海南扩种栽培爪哇白豆蔻的适宜区.     

考虑土壤水平衡的灌区水资源优化配置研究

针对内蒙古河套灌区解放闸灌域地下水埋深较浅且矿化度高及黄河水量逐年减少等因素导致的农业用水严重短缺问题,本研究以解放闸灌域玉米为研究对象,耦合Jensen模型与土壤水平衡模型构建灌区尺度灌溉水资源优化配置模型,对不同的地下水埋深及土壤含水量情景下水资源优化配置方案进行研究,并利用Lingo软件编程求解模型。结果表明:当地下水埋深为2.5m时,引黄水量为3.85×10~8 m~3,可以达到5.55×10~8元的净经济效益;而土壤水含量为0.12～0.16时,净经济效益为[5.41,5.67]×108元。优化结果验证了模型在当地可行,并针对河套灌区解放闸灌域的不同土壤含水量与地下水埋深情景分别提供14种配水方案。     

Changes in mean concentration, phase shifts, and dissipation in a forced oscillatory reaction

Experiments are presented that confirm earlier predictions that the mode of supply of reactants to a nonlinear (bio)chemical reaction determines or controls concentrations at steady states far from equilibrium. The oxidation of nicotinamide adenine dinucleotide (NADH) catalyzed by the enzyme horseradish peroxidase with continuous input of oxygen was studied; NAD+ is continuously recycled to NADH through a glucose-6-phosphate dehydrogenase system. A comparison of steady-state concentrations is made with an oscillatory oxygen input and a constant input at the same average oxygen input for both modes. By varying the frequency and amplitude of the perturbation (O2 influx), the following may be changed: the average concentration of NADH; the Gibbs free energy difference delta G of the reactants and products at steady state; the average rate of the reaction; the phase relation between the oscillatory rate and delta G; and the dissipation. These results confirm the possibility of an "alternating current chemistry," of control and optimization of thermodynamic efficiency and dissipation by means of external variation of constraints in classes of nonlinear reactions and biological pumps, and of improvements of the yield in such reactions (heterogeneous catalysis, for example).     

植物水分亏缺响应中的物质

水分亏缺响应中的物质离子、多元醇、多胺、碳水化合物、氨基酸、蛋白质等,这些物质参与水分亏缺的信号转导,或做为信号转导的结果,对细胞、大分子物质起保护作用,或以其它方式,使植物减轻或免受水分亏缺的不良影响.     

干旱内陆区水平衡基本原理与模型

在深入研究干旱内陆区域大汽水、地表水、土壤水、地下水4水转化规律与过程的基础上，结合水资源计算、评价、利用、保护、规划等实践，应用水资源系统分析和数学建模的原理和方法，提出了干旱内陆平原区地表水、地下水、供需水、耗水4水平衡基本原理以及水平衡模型。     

新疆博斯腾湖流域水平衡模拟分析研究

应用4水平衡原理与水平衡模型，用1960～2000年41年逐月水文系列资料，以1998年为现状水平年，分析博斯腾湖流域无工程措施与有工程措施对水资源转化、平衡、消耗及水环境的影响和响应。     

基于水量平衡法的黄河兰州银滩湿地生态需水分析

以黄河兰州银滩湿地为研究对象,运用水量平衡法对其生态需水量进行计算并根据权重制定补水方案,以湿地植物栖息地需水量对其检验,并对不同生态目标条件下湿地生态需水量进行分析.结果表明:维持芦苇沼泽面积防止其生态特性减退这一低目标的生态需水量为5.12×105 m3,保证沼泽面积、质量,保证动植物栖息地价植以及防治水面的减退和消失这一高目标的生态需水量为6.08×105 m3,这与湿地植物栖息地需水量计算结果相一致,湿地动态补水分为4级,1级7、8、9月份,2级4、5、6月份,3级3、10月份,4级1、2、11、12月份.     

基于水分平衡的黄土区小流域防护林体系高效空间配置

该文对黄土残塬沟壑区和丘陵沟壑区小流域防护林体系高效空间配置问题进行探讨.针对影响水土流失的主要因子--降雨、地形与小流域侵蚀泥沙的来源及水土流失发生发展规律,提出以小流域为单元,基于林水平衡,体现水土保持功能持续提高的水土保持体系高效空间配置原理与技术.小流域防护林体系的配置模式为:①当坡面的坡度＜25°时,营造农地防护林,坡面防护林,农林复合经营,复合农林业经营模式包括隔坡梯田、隔坡水平沟、水平梯田.隔坡面以经济树种为主,隔坡长与田面宽应根据生态经济原则确定,坡面防护林以防止地表股流的冲淘侵蚀为主.②当坡面的坡度＞25°时,应发展林牧业,采取林草复合,封山育林与人工种植相结合的治理模式.③沟谷地配置固沟拦沙滤水林模式,降低流速,减少冲力,拦沙滤水.采取林草复合,封山育林与人工种植相结合,生物与工程相结合的治理模式.防护林体系应基于小流域的水分生态环境合理分布.防护林体系在不同地貌部位的合理配置应遵循不同立地的生物量允许值,林水平衡,适度造林,达到合理的植物配置模式和稳定林分结构.     

华北冬小麦降水亏缺变化特征及气候影响因素分析

为了探究气候变化背景下作物降水亏缺变化规律和影响因素,该文基于华北地区1971－1980年和2001－2010年气象数据和冬小麦生育期资料,研究了冬小麦生育期内降水亏缺变化特点,利用构建的敏感度分析模型探讨了降水亏缺量对主要气候要素的敏感性特征,主要结论：2001－2010年华北中部地区冬小麦全生育期内干旱加重,降水亏缺面积略有增加;播种—返青期内降水亏缺程度自江苏徐州—河南许昌一线往北都有所加剧,返青—拔节期内降水亏缺程度缓解,拔节—抽穗期内降水亏缺程度加重,仅在山西中部太原地区降水略有盈余,抽穗—成熟期内降水亏缺有所缓解;冬小麦拔节—抽穗期降水亏缺量对日照时数高度正向敏感站点最多,主要分布在河北北部地区和安徽省,其次是风速,对温度和降水的高度正向敏感站点最少。该文为制定灌溉定额,农业水资源管理和缓解水资源供需矛盾提供科学依据。     

海珠湿地植物群落与水质的关系

以海珠国家湿地公园一期为研究对象,设置８个样点对海珠湿地的水质状况进行监测．结果表明,再力花（Ｔｈａｌｉａ ｄｅａｌｂａｔａ）＋美人蕉（Ｃａｎｎａ ｉｎｄｉｃａ）－苦草（Ｖａｌｌｉｓｎｅｒｉａ ｎａｔａｎｓ）群落、美人蕉＋菖蒲（Ａｃｏｒｕｓ ｃａｌａｍｕｓ）－苦草群落、再力花＋风车草（Ｃｙｐｅｒｕｓ ａｌｔｅｒｎｉｆｏｌｉｕｓ）－苦草群落和花叶芦竹（Ａｒｕｎｄｏ ｄｏｎａｘ ｖａｒ． ｖｅｒｓｉｃｏｌｏｒ）＋铜钱草（Ｖａｌｌｉｓｎｅｒｉａ ｎａｔａｎｓ）－苦草群落等４个植物群落生长的水体中总磷、总氮、ＮＨ＋４－Ｎ和化学需氧量的浓度均较低,水体水质较好,由此推测苦草对水质净化效果明显．     

北川滑坡迹地植物群落多样性变化及环境解释

  目的  研究震后滑坡迹地生态恢复过程中群落植物多样性变化情况及环境解释。  方法  以北川县凤凰山滑坡迹地土壤和植物群落为对象,将滑坡迹地分为滑坡区、过渡区和未滑坡区,通过典范对应分析(CCA)排序法对3个区域植被变化情况进行分析,并对植物群落分布进行环境解释。  结果  ①2013—2019年,滑坡区和过渡区总体上植物科属种数量增加了4.00%~483.33%,未滑坡区减少了2.00%~37.50%。②滑坡区和过渡区的植物多样性增加了0.02%~483.33%,未滑坡区减少了2.00%~52.94%,且均匀度也有降低。③乔灌草层的CCA排序前2轴特征值之和占总特征值的60%~80%,表明前2轴包含了排序的大部分信息。④土壤pH和团聚体特征对植被分布的影响较大。  结论  滑坡迹地植物群落的多样性有所提高,且环境因子对植物群落有重要影响。图2表5参33