淹水胁迫下毛桃幼苗不同部位叶片的生理反应

Physiological Responses of Leaves from Different Parts of Amygdalus persica Linn.Seedlings against Flooding Stress

[目的]研究毛桃幼苗中部叶片和下部叶片对淹水胁迫耐受性差异及生理机制。[方法]以露地生长的1年生毛桃盆栽实生苗为试材,将其随机放入水槽内淹水,在淹水前夕和淹水后第2、4、6、8、10 d分别取样,测定其中部和下部叶片中可溶性糖、丙二醛(MDA)、脯氨酸(PRO)含量和过氧化物酶(POD)活性4项生理指标,同时观察被淹植株的形态变化。[结果]随着淹水时间的延长,中部和下部叶片的可溶性糖含量均为先升后降,丙二醛(MDA)和游离脯氨酸(PRO)含量持续上升,过氧化物酶(POD)活性逐渐下降。在淹水过程中,中部叶片的可溶性糖、游离脯氨酸(PRO)含量和过氧化物酶(POD)活性一直比下部叶片高。被淹植株叶片逐渐萎蔫、卷曲、干枯,最终脱落,下部叶片较中部叶片形态变化更早。[结论]生理指标和形态特征结果均表明中部叶片比下部叶片对淹水胁迫的耐受力更强。

[ Objective ] To analyze physiological mechanism about the toleration differences of flooding stress on the middle and lower layers leaves of Amygdalus pets]ca Linn. seedlings. [ Method ] Taking one year old Amygdalus persica Linn. seedlings which were planted in the plastic pots as materials, the continuous flooding experiment with plants randomly placed in a tank full of water were conducted. Soluble sugar, MDA, PRO content and POD activity in leaves from the middle and lower layers of the plants were respectively determined at 0, 2, 4, 6, 8 d after flooded; morphological change of the flooded plants were observed at the same time. [ Result ] With the continuous flooding, the soluble sugar contents in the middle and lower layers leaves increased first and decreased later, MDA and free PRO contents increased continuously, POD activities decreased. In the flooding process, the soluble sugar, PRO contents and POD activities in the middle layer leaves were higher than that in the lower layer ones all the time. Leaves of flooded plants became wilting, curl, yellowing and dry, falling at last ; the lower layer leaves changed earlier than the middle layer ones. [ Conclusion] Physical signs and morphological changes showed that the resistant ability against flooding stress of the middle layer leaves were stronger than that of the lower ones.