Studies On The Physiological Characteristic And Resistance Of Drought In Four Nontimbers Under Drought Stress

Studies on the physiological characteristics and mechanism of leaves in Prunus armeniaca L., Prunus saeicina L., Pyrus pyrifolia N. and Prunus persica L. were carried out under four soil moisture gradient(75 % , 65 %, 55% and 45%). The changes on physiological characteristics were measured and analyzed under drought stress. The results were as follows:1 Leaves relative water contentLeaves relative water content of the four nontimbers decreased under drought stress condition. The decreasing degree of LRWC was: Pyrus pyrifolia N. > Prunus saeicina L. > Prunus armeniaca L. > Prunus persica L.2 Plasma membrane permeabilityUnder drought stress, plasma membrane permeability was enhanced. Their decreasing degree was: Prunus armeniaca L. > Prunus saeicina L. > Pyrus pyrifolia N. > Prunus persica L.3 Chlorophyll contentIn water deficit conditions, the total chlorophyll content of the four species decreased. However, changes of the total chlorophyll content did not show significant difference.4 OsmoregulationUnder drought conditions, all of the four species have the abilities to adapting drought environment by increasing the contentration of soluble sugar and proline. The osmotion ability of the four species was: Pyrus pyrifolia N. > Prunus armeniaca L. > Prunus saeicina L. > Prunus persica L.5 SOD activitiesUnder drought conditions, the activity of superoxide dismutase (SOD) increased markedly. The increasing degree was: Pyrus pyrifolia N. > Prunus armeniaca L. > Prunus saeicina L. > Prunus persica L.6 IAA contentThe IAA content of leaves of the four species was significantly less than that of contrast under water stress. The decreasing degree of IAA content was: Prunus armeniacaL. > Prunus per ska L. > Prunus saeicina L. > Pyrus pyrifolia N.7 Chlorophyll fluorescenceChlorophyll fluorescence parameters were changed markedly under drought stress. Which shew that the structure and function of photosystem II was damaged. The damaged degree was: Pyrus pyrifolia N. > Primus saeicina L. > Prunus armeniaca L. > Prunus per sic a L.8 The assessment of drought-resistanceThe resistance of drought on the four species was assessment by using all the sensitive physiological indicators. The ability of drought-resistance was: Prunus armeniaca L. > Primus persica L. > Pyrus pyrifolia N. > Prunus saeicina L.