水分胁迫下2种沙枣的抗旱性比较

Drought Resistance of Two Elaeagnus Species under Water Stress

在新疆和田墨玉县选取2年生大果沙枣和尖果沙枣实生苗,移植于苗圃对其进行不同灌水量的处理,不同处理的土壤含水量分别为田间持水量的85%、70%,47%和24%。测定了不同处理的大果沙枣、尖果沙枣的水势、净光合速率、蒸腾速率、稳定碳同位素。结果表明:大果沙枣、尖果沙枣在一天中的水势变化趋势呈"V"字型,大果沙枣的日平均水势((-0.87±0.18)Mpa)比尖果沙枣的大;相同处理下大果沙枣的日平均净光合速率((10.03±1.19)μmol.m-2.s-1)和蒸腾速率((11.06±0.88)mmol.m-2.s-1)均比尖果沙枣的大;大果沙枣的瞬时水分利用效率((0.80±0.09)μmol.mmol-1)也比尖果沙枣的高;大果沙枣的1δ3C值(-26.06‰±0.08‰)显著比尖果沙枣的大。土壤含水量为田间持水量的85%、70%和47%时,大果沙枣和尖果沙枣生长状况都良好,土壤含水量为田间持水量的24%时,大果沙枣和尖果沙枣干旱胁迫明显,但是大果沙枣的净光合速率和水分利用效率比尖果沙枣分别高3.26μmol.m-1.s-1、0.06μmol.mmol-1,大果沙枣水势比尖果沙枣低0.06 Mpa,运用隶属函数对各个指标的综合比较结果表明,大果沙枣比尖果沙枣的抗旱性强。

Two years old seedlings of Elaeagnus moocerofiii and Elaeagnus oxycarpa were chosen and planted in field, then treated by different mount of irrigation in Moyu county of Xinjiang. The relative mean soil water contents of different irrigating treatment were 85%, 70%, 47% and 24%. by to measuring the water potential of E. moocerofiii and E. oxycarpa under different conditions and at different time, it was shown that their variation trends followed a ＂V＂ shape in whole day. The mean daily water potential of E. moocerofiii （ （ -0.87±0.18） Mpa）was higher than that of E. oxycarpa. Comparing the net photosynthetic rate, transpiration rate and water use efficiency of two species, it is turned out the net photosynthetic rate（ （10.03±1.19）μmol· m^-2·s^-1）, the transpiration rate（ （11.06±0. 88 ）mmol· m^-2·s^-1） and water use efficiency （ （0. 80±0. 09 ） μmol· m-1 ） of E. moocerofiii were higher than that of E. oxycarpa. The δ^13C value of E. moocerofiii （-26.06‰±0.08‰）was significantly higher than that of E. oxycarpa. The E. moocerofiii and E. oxycarpa grew well when the the soil water contents of different irrigating treatment were 85% ,70% and 47%, while it was under significantly drought stress when under the soil water contents of different irrigating treatment were 24%, but the net photosynthetic rate and water use efficiency of E. moocerofiii were 3.26μmol·m^-2·s^-1,0. 06μmol·mmol^-1 higher than that of E. oxycarpa. The water potential of E. moocerofiii was 0.06 Mpa lower than that of E. oxycarpa. In a word, the drought resistance of E. moocerofiii was better than that of E. oxycarpa by Subordinate Function Value.