干旱

Approaching of osmotic adjustment in Epacris obtusifolia, Eucalyptus obtusifolia and Eucalyptus gummsfelia was made by pressure-chamber technique under drought stress.

用P-V曲线技术研究了三种海滨木本植物在干旱胁迫条件下渗透调节的能力。

The leave of the most species became smaller and lush epiderm was hairs and developed thick cuticle.

这样的结构能有效利用水分，减少强烈蒸腾，增强光和作用，抵抗干旱胁迫。

The vertical roots of short-lived grasses Erodium axyrrhynchum and annual grasses Ceratocarpus arenarius formed before May so to avoid the drought season.

3一年生草本植物角果藜的根系垂直生长主要发生在4月至5月中旬，短命植物尖喙牻牛儿苗的根系垂直生长主要在5月之前，两者都是在干旱季节来临之前垂直根迅速生长，以增加水分吸收。

ABSTRACT This dissertation, based on the theories of geography, ecology, economics, sociology and environmental sciences, has analyzed the impact of transition between cultivation and pasture animal husbandry on the mechanism of desertification in Kerqin Sandy Region, of which behavior mechanism of local people was emphasized. The changing direction of integrated land desertification control strategy in semi-arid regions was discussed after having explored the primary reasons of estrepement, overgrazing and excessive firewood gathering. Followings are the main research works having been done.

本文选取科尔沁沙地作为研究区域，以两种最主要的土地利用方式、也是两种最主要的生产方式——农、牧业作为研究对象，依据地理学、生态学、经济学、社会学与环境科学的基本理论与方法，基于现有研究资料的系统整合，结合野外调查的结果，从更加综合的角度，来研究农、牧业选择变化对沙漠化过程的影响机理，从农、牧业选择变化的角度来揭示&滥垦、滥牧、滥樵&的本质，进而寻求中国北方半干旱地区生态环境综合整治的对策。

Results are as following:The causes of grassland desertification of Hulunbeir are the outcome of interaction of nature and the human beings. Among these reasons, the loose soil texture, which was formed in the fluviolacustrine sediment during Quaternary, establish the physical ground, and the drought and wind is the natural force of grassland desertification. And then over-cutting forest, over-grazing grassland, imbalance of resource utilization and estrepement reduce the coverage of vegetation, therefore provide necessary conditions for the grassland desertification.

其中，形成于第四纪河湖相沉积沙的疏松土壤母质，为日后土壤风蚀奠定了深厚的物质基础；干旱多风的气候条件构成了草地风蚀沙化的自然营运力；而人为过度砍伐沙地林木资源、沙质草地长期超载放牧、资源利用不平衡以及乱垦、滥挖等不合理经济行为，又降低了沙化草地植被覆盖度，为草地风蚀沙化提供了必要条件。

Jatropha curcas, belonging to Euphorbiaceae and thriving in many parts of the tropics and sub-tropics around the world, is a multipurpose plant with many attributes and considerable potentials.

麻疯树为大戟科麻疯树属的一种油料植物，抗病虫和耐干旱能力强，在热带和亚热带地区有大量分布，是一种具有较大开发潜能的植物。

Based on the fieldwork , this paper deals with the structure of exogenic force in the north terrain of loess hilly gulied plateau in north Shaanxi Province. The author thinks that the structure research is a key to reco-gnize the feature of the local landform and its development.

根据野外初步观察，提出陕能黄土高原北部半干旱边缘地带的侵蚀营力结构问题进行讨论，分析了营力性质构成及营力结构的地域分异，对综合分析本区的土壤侵蚀问题有一定意义。

The glumes are very variable even in the terminal, exserted inflorescences.

本种的大的比例包括半干旱的地区的植株，在那里他们提供有用的饲料。

Medicago falcata L. belongs to drought avoidance type in the method of drought resistance.

在抗旱方式上，黄花苜蓿属于干旱避免型。

The results were as follows: 1. Response of physiology indices of Medicago falcata L. to drought stress is different. There are not obvious correlation among indices and ability to drought resistance. The indices include critical water saturation deficiency, free and bound water content, tissue water, peroxidase isozyme, free proline content, chlorophyll a, chlorophyll b, total chlorophyll and chlorophyll. These indices are not fitting for assessing ability of drought resistance of Medicago falcata L..

黄花苜蓿各生理指标对干旱胁迫的响应不同，临界饱和亏、自由水含量、束缚水含量、组织水含量、过氧化物同工酶、游离脯氨酸含量、叶绿素a、叶绿素b、叶绿素总量以及叶绿素与黄花苜蓿抗旱能力之间不存在明显的相关性，不适宜采用这些指标来评价或判别黄花苜蓿材料间抗旱能力的强弱。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。