Effects Of Seedling Growing And Physiologic Index Of Different Maize Genotypes(Zea Mays L. ) Under Drought Stress

The drought caused the corn yield to decrease greatly. In order to investigrate the drought resistance of different genotypes of maize, in order to provide the theoretical basis for the seeding water control and corn varieties screening and application. In this study, sweet corn(Guangtian No. 2 and Zhongxian sweet No. 3), waxy corn(Zhongnuo No. 2 and Beijing Nuo 2000), the common corn(Zhengdan 958 and Nongda 108) as the experimental material,through the pot experiment, set up 4 water treatment: The soil moisture content is 85%~90%of field capacity(control), the soil moisture content is 65%-70% of field capacity(mild water stress), the soil moisture content is 45%-50% of field capacity(moderate water stress), the soil moisture content is 25%-30% of field capacity(severe water stress). Study on changes of3 types of 6 corn varieties in seedling morphological indexes and physiological indexes. The main results are as follows:Effects of water stress on morphological indexes of 6 corn varieties: Under drought stress at seedling stage, the plant height, stem diameter and leaf area decreased. Under mild water stress, compared with the control was not obvious, under moderate water stress and severe water stress was remarkable. With the increasing of water stress, the shoot dry weight and dry matter accumulation was decreased. The derease rate of 6 corn varieties plant height,stem diameter, shoot dry weight, dry matter accumulation and leaf area: Nongda 108>Zhengdan 958 > Zhongnuo No. 2 > Beijing Nuo 2000> Zhongxian sweet No. 3 > Guangtian No. 2. There were some differences between the derease rate of 6 maize varieties, but there was a certain regularity. Under the mild water stress, the content of the indicators had little change. Under the moderate and severe water stress, it changed larger.Effects of water stress on physiological indexes of 6 corn varieties: the drought stress made osmotic substance increased. The content of proline and soluble sugar increased significantly with the increasing of water stress. The increase is not consistent in all varieties.The leaf relative water content and soluble protein content showed a significant declining trend. Under mild water stress, the derease rate is relatively slow, moderate water stress andsevere water stress decreased more quickly. 6 corn varieties SOD, POD and CAT activity in the leaves under water stress were showing a downward trend after the first rise, but slightly different. The order of magnitude of enzyme activity changes in various corn varieties:Nongda 108> Zhengdan 958 > Zhongnuo No. 2 > Beijing Nuo 2000> Zhongxian sweet No.3 > Guangtian No. 2. The cell membrane permeability of 6 corn varieties increased with the increasing degree of water stress. Mild water stress, moderate water stress and severe water stress, compared with the control showed significant differences. Water stress made different corn varieties chlorophyll content and chlorophyll a/b increased significantly, the largest increase in normal corn, waxy corn medium, sweet corn minimum.For the determination of various morphological indexes and physiological indexes 3types of 6 corn varieties, that is a complex process, is the result of interaction of different drought resistance mechanism. The drought resistance of 6 corn varieties by fuzzy membership function is analyzed. The ability of drought resistance of 6 corn varieties:Zhongxian sweet No. 3> Guangtian No. 2>Beijing Nuo 2000>Zhongnuo No. 2 >Zhengdan958>Nongda 108. It can be seen from the experimental results, sweet corn > waxy corn > the common corn, it may also be because of drought resistance of corn varieties associated with the genotypes of maize varieties.