PEG-6000模拟干旱胁迫对香果树种子萌发及幼苗生长的影响

Effect of PEG-6000 Simulated Drought Stress on Seed Germination and Seedling Growth of Emmenopterys henryi Oliv

为研究PEG-6000模拟干旱对香果树种子萌发及幼苗生长发育的影响,PEG-6000浓度设置5个梯度以及对照组(ck)。结果表明,与ck相比,T1、T2浓度并不影响香果树种子的发芽率,发芽率能达到85%以上,T3浓度下发芽率下降到70%,T4、T5浓度下种子不发芽;发芽势随着PEG-6000浓度的增加逐渐降低。干旱处理40 d后,香果树幼苗地上鲜重及根鲜重随着PEG-6000浓度的增加显著下降,即使T1浓度下,香果树幼苗鲜重也仅有ck的1/16。并且在持续干旱处理中,香果树幼苗死亡率随PEG-6000浓度增加而上升,T3处理下死亡率达77%,仅剩的几株幼苗生长也受到极大限制。与ck相比,PEG-6000处理显著抑制叶片数量、叶面积的增加,并显示出剂量效应。与ck相比,PEG-6000处理显著抑制主根的伸长和侧根的形成,侧根量随着浓度的增加显著降低,但是主根长在T1、T2和T3处理之间差异并不显著。香果树耐旱能力较差,推测是香果树种群数量下降的原因之一,本研究结果为香果树种群的恢复和管理提供了科学依据。

The effects of PEG-6000 simulated drought on seed germination and seedling growth of Emmenopterys henryi Oliv were studied.The concentration of PEG-6000 was set in 5 gradients of 5%(T1),10%(T2),15%(T3),20%(T4),30%(T5) and the control group(ck).The results showed that T1 and T2 concentrations did not affect the seed germination rate of Emmenopterys henryi Oliv compared with the control,which could reach more than 85%.The seed germination rate dropped to 70% at T3 concentration,and the seeds did not germinate at T4 and T5 concentrations,the germination potential gradually decreases with the increase of PEG-6000 concentration.After 40 days of drought treatment,the shoot fresh weight and root fresh weight of the Emmenopterys henryi Oliv seedlings decreased significantly with the increase of the PEG-6000 concentration.Even at the T1 concentration,the shoot fresh weight of the Emmenopterys henryi Oliv seedling was only 1/16 of the ck group.In addition,in the continuous drought treatment,the mortality rate of the Emmenopterys henryi Oliv seedlings with the increase of the PEG-6000 concentration,and the mortality rate reached 77% under the T3 treatment,the growth of the few surviving seedlings was also greatly restricted.Compared with ck group,PEG-6000 treatment significantly inhibited the increase in leaf number and leaf area,and showed a concentration effect.PEG-6000 treatment significantly inhibited the elongation of the primary roots and the formation of lateral roots compared with ck group.The amount of lateral roots decreased significantly with the increase of PEG-6000 concentration,but the difference in the length of the primary roots between T1,T2 and T3 treatments was not significant.Emmenopterys henryi Oliv had poor drought tolerance,which maybe one of the factors that contributed to the decline in the population of Emmenopterys henryi Oliv.The experimental results provided a scientific basis for the restoration and management of Emmenopterys henryi Oliv.