淹水胁迫对湖北海棠生长和生理特性的影响

摘要

为研究淹水胁迫下湖北海棠幼苗生长、形态和叶片生理特性,以湖北海棠3年生幼苗为试验材料进行试验,结果表明:(1)淹水处理下,湖北海棠幼苗存活率为100%,但叶色及形态发生了显著的变化.其中,淹水前期叶色由绿色向紫红色转变;淹水后期,叶片颜色由紫红色向黄绿色转变,茎基部皮孔变得肥大且数量显著增加;在淹水49 d时,较多数量的不定根从茎基部皮孔伸出.(2)长期的淹水胁迫会抑制湖北海棠幼苗的苗高生长和地径增长;(3)淹水胁迫抑制了光合色素的合成,降低了叶绿素和类胡萝卜的含量,叶绿素a与叶绿素b的比值下降,而类胡萝卜素与叶绿素的比值升高.(4)叶片中的MDA含量呈现出先上升后下降的趋势,除淹水前期外, MDA的含量显著高于对照(P<0.01).(5)叶片SOD酶活性总体呈现出先升高、后下降的趋势.其中,淹水前期(21 d),SOD酶活性呈上升趋势;此后,SOD酶活性下降,但仍显著高于对照(P<0.05).(6)淹水促进了叶片可溶性糖含量的显著上升(P<0.01).这些说明湖北海棠在淹水下可以通过形成较多数量的肥大皮孔、不定根以及保持较高的碳水化合物水平和较高的SOD酶活性来缓解淹水逆境对其造成的伤害.因此,湖北海棠属于耐水涝的观赏树种,可在洪涝多发区(如沿江、沿海等)推广种植.%In order to research growth, morphology, and physiological indexes of Malus hupehensis leaves under waterlogging stress, 3-year-old M. hupehensis seedings as materials were tested. The results demonstrate that: (1) Survial rate of M.hupehensis seedings was 100% during waterlogging stress,but leaf color and morphology changed significantly.Leaf color changed from green to amaranth during the early waterlogging period,and then changed from amaranth to yellowish green,and stem lenticels became larger and had a significant increase of number during the later waterlogging period. A large number of adventitious roots emergenced from lenticels at the stem base on the 49th day of waterlogging. (2)The growths of height and ground diameter in M. hupehensis seedlings were inhibited in long-term waterlogging stress. (3) Waterlogging stress inhibited synthesis of photosynthetic pigments, decreased chlorophyll content, carrot content and ratio of chlorophyll a to chlorophyll b, however, increased ratio of carotenoid to chlorophyll. (4)MDA content in leaves showed a tendency of firstly increased and then decreased,MDA content was significantly higher than that of the control (P<0.01) except for the early waterlogging period. (5) SOD activity in leaves showed a tendency of firstly increased and then decreased.SOD was increased during the early waterlogging period(21 d),then decreased,but was significantly higher than that of the control(P < 0.05).(6)Soluble sugar content was significantly promoted under waterlogging stress.These results suggest that M.hupehensis seedings can alleviate damage caused by waterlogging by forming a large number of larger lenticels and adventitious roots and maintaining higher carbohydrates level and SOD activity.Thus,M.hupehensis belonged to ornamental tree species with waterlogging tolerant and can be extened in flooding areas.