Effects Of Water Stress On Physiological Characteristics And Bioactive Constituents Of Eucommia Ulmoides Oliv.

Using three different annuals of Eucommia ulmoides as experiment materials and pot culture experiments simulating different soil water status, this paper mainly dealed with water consumption characteristic and growth ,protective enzymes activities, osmotic regulation substances and bioactive constituents, we expected to discover difference of drought-resistance mechanism and comprensive evaluate. The main results were as follows:1.Different soil water contents had obvious affected on water consumption of three annuals of Eucommia ulmoides.The highest water consumption of Eucommia ulmoides in a month concentrated on June and 1a Eucommia ulmoides has no obvious highest water consumption .The time of highest water consumption in a day advanced. Soil water decided on water consumption, the trends are normal water>medium stress>severe stress. The photosynthetic rate of Eucommia ulmoides was restrained and the transpiration rate of 3a and 2a Eucommia ulmoides was advanced under drought stress.The growth of Eucommia ulmoides had been restrained and WUE advanced under drought stress,but the chlorophyll content had no obvious change ,the retained water capacity of 2a Eucommia ulmoides advanced.2 Under medium stress,activities of SOD,CAT of 2a Eucommia ulmoides had increased in early stage of water stress, the content of MDA was lower .Because of decreasing of protective enzymes activities, the content of MDA was highest on 90d stress. Protective enzymes activities were lower and the content of MDA was higher in the later stage of severe stress.The contents of soluble protein,sugar were increasing under drought stress and the change of pro content was little.therefore,the ability of osmotic regulation of 2a Eucommia ulmoides concentrated on soluble protein and sugar.3 Using potted 2a seedlings of Eucommia ulmoides,a study was conducted to determine the effect of drought stress and rewatering on physiological characteristics.The results showed that the activities of SOD,POD,CAT and the content of proline increased firstly and decreased then with prolonging drought stress time ;the content of MDA raised firstly,declined then,and increased later;the content of soluble protein changed like'M';the content of soluble sugar increased continually.All physiological indexes,except the content of soluble sugar,restored to lower level after 2d rewatering.4 The effects of protective enzymes activities and osmotic regulation substances were different on three annuals of Eucommia ulmoides under different water contents.Application of principal analysis to evaluate drought resistance of Eucommia ulmoides,the result showed that drought-resistance arranged is 2a>1a>3a.5 The effect of PAL activity was different on three annuals of Eucommia ulmoides under different water contents. Compred with normal water treatment,the content of chlorogenic acid of 1a Eucommia ulmoides decreased and 2a,3a Eucommia ulmoides increased under drought stress.The content of geniposidic acid of Eucommia ulmoides increased and the content of flavonoids had no regular changes under drought stress.All datas were analysed by analysis of variance and the results were showed the effects of PAL acyivity,the contents of chlorogenic acid, geniposidic acid, flavonoids were different on different annuals of Eucommia ulmoides under different water contents (p<0.05).