Differential Tolerances Among Tropical Forage Crops to Water Deficit Conditions.

本研究的目的是评估作物对水分胁迫条件的形态和生理适应，以评估它们的干旱耐旱能力。分别在温室、大田和水培条件下种植植物，并对其进行水分胁迫。水分胁迫对供试植物的生长有显著影响。相对生长率(RGR)和净同化率(NAR)在胁迫条件下呈下降趋势，不同作物间差异显著。在水分胁迫条件下，RGR和NAR的下降百分比被用来作为抗旱性的指标。它在罗得斯草中含量很低，在乔德的眼泪中含量很高。而叶面积比(LAR)不受胁迫的影响。由于水分胁迫，光合作用速率下降，特别是在约伯的泪水中。胁迫提高了月见草的水分利用效率，而降低了约伯的水分利用效率。罗德斯格拉斯能够维护照片…与其他作物相比，胁迫下的合成产量更多，因此RGR和NAR没有明显下降。在胁迫条件下，高粱和乔伯叶的14&gt；C同化物在叶和茎中得到修复，其同化物从叶到腐烂的转运显著减少。腐烂果实中蛋白质、木质素-纤维素组分等高相对分子质量组分中的14&gt；C含量明显降低。同时，胁迫使根的水分导度(RAC)显著延长。罗得斯草的RHC比约伯的眼泪长几倍。在水分胁迫下，两种植物的~3H2O在植物体内的运移均显著减少。添加~1H_2O后20h，根、茎、展开叶和叶组织水中的相对放射性分别为营养液的15%、45%、9.5%和8.5%。《约伯的眼泪》分别为48、17、5.1和3.8%。与红花草相比，乔布的眼泪中~3H2O从根到地上部，尤其是到叶的移动受到了强烈的限制。结果表明，不同树种的抗旱性不同，其抗旱性也不同。主要的水分阻力如何通过植物存在于节上，以及位于中转位置的基茎似乎从一个器官转移到另一个器官。较少

The objective of this study are evaluation of morphological and physiological adaptation of the crops to water stress conditions to estimate their drought to lerant ability. Plant were grown foth in green house, field condition and water culture and subjected to sequence to water stress. The plant growth of tested plants was Affected remarkably due to water stress. The Relative Growth Rate (RGR) and Net Ossimilation Rate (NAR) decreased under stress conditions and significant differences were observed between crop species. The reduction percentage in RGR and NAR under water stress condition was used as an indicator of tolerances to drought. It was low in Rhodesgrass and high in Jod's tears. However, Leaf Area Ratio (LAR) was not effected by stress. The photosynthetic rate was reduced due to water stress, spedially in Job's tears. Water use efficiency in Rhodesgrass was increased by strees, whereas that of Job's tears was severely decreased. Rhodesgrass was capable of maintaining photos … More ynthetic production under stress and therefore RGR and NAR were not decreased considerably compared to other crops under stress conditions. ^<14>C aseimitates remedied in leaves and stems and the tanslocation of ^<14>C assimilates from leaves to rots was remarkably reduced under stress conditions in sorghum and Job's tears. ^<14>C content in high-molecular weight constituents such as protein and ligin-cellulose fraction in rots was apparently reduced by stress in Job's tears. And also root hydrautic conductivity (RAC) was considerably longer due to stress. The RHC of Rhodesgrass was there times longer than of Job's tears. The movement of ^3H_2O through plant were remerbobly reduced in both species under water stress. Twenty-Foun hours after added of ^3H_2O, the relative radioactivity in tissue water of root, stem, expanded leaves and ehponding leaves were 15, 45, 9.5 and 8.5% respectively, compared to that of nutrient solution on Rhodeagrass. The respective values in Job's tears were 48, 17, 5.1 and 3.8%. The movement of ^3H_2O from root to shoots, especially to leaves was strongly restrictebl in Job's tears compared to Rhodesgrass. The results indicated that the resistance to water how through plants differ among species according with their drought to lerant ability. The major resistance to water how through plant appers to be exist in the nodes and for the basal stems which are located in transit positions appears from organ to another. Less