Evaluation Of The Drought Tolerance Of Six Herbaceous Ground Cover Plants In Chongqing

In this research,6 herbaceous ground cover plants from Chongqing were used as the experimental materials. The variation of morphological index and physiological and biochemical indexes were studied and furthermore, comprehensive evaluation of drought tolerance was carried out through subject function and index scheduling superposition.The morphological indexes measured included:plant height, root dry weight, leaf number, single leaf area, leaf dry weight, leaf fresh weight, leaf water content, and so on; physiological and biochemical indexes included:chlorophyll content, cell membrane permeability(relative electric conductivity REC), free proline content, MDA content, soluble protein content, SOD,CAT and POD.The main conclusions include the following:1. The effect of drought stress on morphological indexes of 6 herbaceous ground cover plantsWhen the 6 herbaceous ground cover plants were subjected to drought stress, all morphological indexes were affected. Index values decreased significantly to varying degrees compared with that of the control, suggesting that morphological indexes are sensitive to water stress in most herbaceous ground cover plants. All the index values decreased with the increased intensity of drought stress. Some index values of the 6 ground cover plants differed significantly between moderate and severe drought stress.2. The effect of drought stress on physiological and biochemical indexes of 6 herbaceous ground cover plantsAfter water stress, all the physiological and biochemical indexes varied, which suggested the sensitivity to drought. All indexes declined to different degrees due to different plants, while the REC values increased compared with the control, suggesting the difference of drought tolerance between the 6 plants. The sensitivity of all the indexes to water stress differed due to different plants. Meanwhile, the variety development phenotype of these six herbaceous ground cover plants is different in the sensitivity of water after water stress.3. Comprehensive evaluation of drought resistance of 6 herbaceous ground cover plants.The drought resistance of plants was discovered to be a complex trait by measuring a variety of physiological and biochemical indexes of 6 herbaceous ground cover plants. The drought resistance of plants was the combination of various drought resistance mechanisms, and any single indicator cannot explain very well the strength of plant drought tolerance. In order to obtain more accurate conclusions, subordination function and Index Superposition method, which belong to fuzzy mathematics, were used for comprehensive evaluation of the 6 herbaceous ground cover plants. Finally, according to the results of two evaluation methods, the 6 herbaceous ground cover plants were sorted on the drought resistance. The decreasing order was:Imperata cylindrica> pennisetum alopecuroides＞Eragrostis ferruginea＞Setaria plicata＞Ophiopogon japonicus＞Iris japonica Thunb.The comparison results of Drought tolerance of 6 herbaceous ground cover plants showed that cogongrass had a good drought tolerance. It was the most appropriate to be extended and used for slope protection. Pennisetum, weeping love grass and wrinkled leaf bristlegrass had a moderate drought tolerance, and could be used in slope protection land with better water and soil conditions. Liriope and fringed iris rhizome were unsuitable for slope protection and greening with their weak drought tolerance, they could only be planted in damp forests.