不同植物在水分胁迫条件下脯氨酸的累积与抗旱性的关系

Ca植物春小麦幼苗叶片累积脯氨酸的数量随水分胁迫时间和强度递增,累积的数量与品种的抗旱性没有相关性。C_4植物玉米和高粱累积脯氨酸的数量低于小麦,但高粱多于玉米。CAM植物落地生根脯氨酸含量略有变化。旱生植物细枝岩黄芪的同化枝累积脯氨酸的数量高于中生植物钻天杨和槐的叶片,而梭梭的同化校则低于槐而高于钻天杨。表明这些植物累积脯氨酸的数量与它们的抗旱性无夫。因此似不宜用脯氨酸数量的多少作为植物抗旱性的生理指标。     

不同干扰方式对内蒙古典型草原植物种组成和功能群特征的影响

研究休牧、补播和自由放牧3种人为干扰方式对内蒙古典型草原群落植物种组成、功能群组成、群落物种多样性和地上生物量的影响.结果表明: 3种干扰方式对植物功能群结构及其多样性有显著影响,休牧方式下群落植物种数量、地上生物量、多样性指数和丰富度指数最大,分别为22种、171.32 g·m^-2、1.46和5.7,灌木半灌木和多年生禾草的重要值、物种所占比例、地上生物量、多样性指数、丰富度指数和均匀度指数显著高于其他干扰方式,多年生杂类草的重要值、物种所占比例、地上生物量、多样性指数和均匀度指数显著低于其他干扰方式,中生植物、C3和C4植物的地上生物量最大,分别为22.22、143.35和27.97 g·m^-2.补播方式下,中旱生植物地上生物量最大,为13.60 g·m^-2,旱生植物物种所占比例最小(48.5%),C4植物物种所占比例最大(28.8%).自由放牧方式下,一、二年生草本植物物种所占比例最大,达12.3%,中生植物和C4植物所占比例最小,分别为17.0%和20.9%.春季休牧措施有利于退化草原的恢复.     

The Effects of Drought on the Water Balance and Nitrogen Metabolism in Sand-fixing Plants

The changes in water balance and nitrogen metabolism of sandfixing plants under soil drought condition in desert area were studied. During sustained drought, the free water content was decreased and the bound water content was increased in all of the experimental plants. Nitrogen metabolism in the plants was converted by drought. The protein synthesis was inhibited, in the meantime the non-protein nitrogen was accumulated. It was found that a notable difference exists in various plants as far as accumulated non-protein nitrogen is concerned, amide nitrogen was accumulated mainly by xerophyte Hedysarium scoparium and nitrate nitrogen by mesophyte Robinia psudoacacia. The water balance of plants and the role of bound water in drought resistance are also discussed.     

黑龙江镜泊湖熔岩台地种子植物多样性

在野外调查和标本采集鉴定的基础上,对镜泊湖熔岩台地种子植物多样性进行了统计分析,结果表明:镜泊湖熔岩台地有野生种子植物81科270属493种,11个优势科含有的属、种数分别占50.74%和53.75%;优势科具有11个属和17个种的分布区类型,温带成分占主体;植物资源按其性质和用途分为药用、观赏等12类;按Raunkiaer生活型分类,以地面芽和一年生植物居多;按中国植被生活型分类,以多年生草本占优势,其次为一年生草本;在水分生态类型中,中生植物是主要的生态类型,旱生植物占总种数的7.51%.火山地貌对植物多样性具有深刻影响.     

CO２浓度和温度升高对11种植物叶片解剖特征的影响

以生长在严格控制的温度梯度,以及温度和CO2浓度梯度2个温室里的8种美国中西部弃耕地常见草本植物和3种美国东部落叶阔叶林优势木本植物为材料,通过比较叶片栅栏组织厚度、海绵组织厚度、和叶片总厚度的变化,探讨CO2浓度和温度升高对不同功能型植物叶解剖特征的影响。结果表明：当温度升高时,C4植物的叶片厚度增加,而C3植物叶片厚度的变化无明显规律;当CO2浓度升高时,9种C3植物中有7种植物的叶片总厚度增加,而C4植物叶片厚度减少。植物叶片解剖特征沿CO2浓度和温度梯度呈现线性和曲线变化趋势;不同物种的同一组织厚度和同一物种的不同组织厚度,对温度和CO2都升高或仅仅温度升高的反应都存在很大的差异。在未来全球变化情况下,植物叶片对CO2和温度升高的反应存在明显的种类差异。由于植物的结构和功能是相关联的,这种解剖结构的改变将可能引起植物功能上对CO2和温度升高反应的差异。     

Estimation of uranium and boron contents in plants and soils by nuclear particle etch technique

Summary The nuclear particle etch technique has been utilized to estimate uranium concentration in soil and plant samples and boron contents in plant samples. The average value of uranium content in soil was found to be 11 ppm. Uranium was found to vary from 0.5 to 4.4 ppm and boron was found to vary from 10.9 to 19.2 ppm in plant (mesophyte and xerophyte groups) samples. The present technique of nuclear charged particle track analysis, simple and inexpensive, has high potentiality for boron and uranium analysis in plants and agricultural crops. It may find application in geobotany to get information about underlying deposits of ores and minerals.     

青海省芨芨草草原的群落特征及其分布规律

芨芨草(Achnatherum splendens)是一种旱生植物,广泛分布于欧亚草原和荒漠地区。它是一种生态可塑性很强的植物,可分布于草原、荒漠草原等植被带内。以其为优势种可以形成盐生草甸、草原、荒漠草原等多种植被类型。青海省共和盆地、青海湖盆地和柴达木盆地东部等地大面积分布有芨芨草群落,并和本区分布的其他草原类型形成基带植被。无论是其生境条件、生物生态学特性、群落的组成及分布规律均具有草原性质,应划归草原植被类型较为合适。     

黄土高原地区种子植物区系中的珍稀濒危植物研究

黄土高原地区植物区系是南北和东西区系成分的交汇 ,也是旱生、中生和湿生植物聚集的地区 ,生长着比较丰富的植物种类 ,有种子植物 32 2 4种 ,其中珍稀濒危植物 78种 ,分别隶属于 4 3科 6 6属 ,国家一类保护植物 2种 ,国家二类保护植物 10种 ,国家三类保护植物 15种 .地理成分分析表明 ,在属一级水平上以北温带成分、中国特有成分、东亚成分为主 ,种一级水平上以华北区系成分为主 .另外 ,在分析黄土高原珍稀濒危植物致濒机制的基础上 ,进一步提出了保护对策     

放牧对内蒙古锡林河流域草地群落植物茎叶生物量资源分配的影响

以内蒙古锡林河流域沿水分梯度分布的灰脉苔草(Carex appendiculata)、贝加尔针茅(Stipa baicalensis)、羊草(Leymus chinensis)、大针茅(Stipa grandis)、小叶锦鸡儿(Caragana microphylla)和冷蒿(Artemisia frigida) 6个草地群落为对象, 研究了围封禁牧与放牧样地中144个共有植物种的高度、丛幅面积、茎、叶和株(丛)生物量、茎叶比等性状。结果表明: 1)在个体水平上, 放牧样地中植物的生殖枝高度、营养枝高度、丛幅面积、单株(丛)生物量、茎、叶生物量和茎叶比均显著低于围封禁牧样地, 植物在放牧干扰下表现出明显的小型化现象; 2)在群落水平上, 放牧亦显著降低了群落总生物量和茎、叶生物量; 3)过度放牧显著改变了物种的资源分配策略, 使生物量向叶的分配比例增加, 向茎的分配比例减少。资源优先向同化器官分配可能是植物对长期放牧干扰的一种重要适应对策; 4)轻度放牧对物种的资源分配没有显著影响, 单株(丛)生物量和群落茎、叶及总生物量均表现出增加趋势, 这与过度放牧的影响正好相反。过度放牧引起的植物个体小型化改变了生态系统中物种的资源分配策略, 进而对生态系统功能产生重要的影响。     

The Fundamental Characteristics of the Steppe Vegetation in Xizang Plateau

The steppe vegetation of the Xizang (Tibet) Plateau is somewhat similar to the temperate steppe of our country, but it possesses its own characteristics: 1. The elements of the Qinghai-Xizang floral region or plant species taking the Qinghai-Xizang Plateau as their chief distribution center play a dominant part in tile constitution of the steppe communities. In these communities, the plants are usually sparse and dwarf, their growth period is shorter and the biological productivity is lower than the steppe in the temperate zone. They possess synusia consisting of herbaceous plants fit for cold climate, synusia consisting of kobresia and synusia consisting of cushion plants. 2. There are 4 types of steppe vegetation in the Xizang Plateau. And the tussock-grass steppe is the most typical. According to their different ecological characteristics, they may be divided into 3 types. Of these, the most widely distributed type is the cold temperate-weak semiarid steppe. And there are many characteristical steppe communities. 3. Distributionally, the steppe in the Xizang Plateau belongs to a special type of vertical distribution in the subtropical latitude zone, it is different from the gene- rally known montane vertical belt, and possesses a vertical-horizontal distributive nature, i.e. "zonation of plateau". Within the Plateau steppe region, steppe eommunities with different ecological characteristics have clearly marked areal differentiaton, and which has determined the nature of the vertical belts in these areas. According to different basal belts of the vertical belt spectrum, such belts may be divided into 3 types. There are no forests in the montane vertical belt spectra in the Plateau steppe region, and the upper distributional limit of the steppe vegetation reaches an altitude of about 5200 (5400) m., which is the highest distributional limit of steppe on the earth.