涝渍胁迫对不同树种生长和能量代谢酶活性的影响

为了解涝渍条件下不同树种的耐涝性和适应性,通过田间模拟试验,分析了涝渍胁迫对1年生落羽杉、美国山核桃和乌桕实生苗生长及能量代谢酶的影响.试验分为对照、渍水和淹水3个处理,处理时间为60 d.结果表明：在渍水和淹水条件下,3种树种的相对生长率均表现为落羽杉>美国山核桃>乌桕,落羽杉耐涝性最强,乌桕耐涝性最弱.涝渍条件下,3种树种的根冠比显著增加,更多的光合产物被分配到根系.3树种乙醇脱氢酶和乳酸脱氢酶活性显著升高,其中耐涝性强的落羽杉增加幅度不大,但一直维持在较高水平;而乌桕和美国山核桃在处理初期增幅较大,在处理后期呈下降趋势.3种树种的苹果酸脱氢酶、磷酸己糖异构酶和葡萄糖-6-磷酸脱氢酶-6-磷酸葡萄糖酸脱氢酶的活性均低于对照,其中落羽杉降幅最低,淹水条件下分别下降35.6%、21.0%和22.7%.耐涝性强的树种能够通过自身的调节,维持各种能量代谢途径的强度,为树种在低氧条件下的生命活动提供能量,进而维持一定的生长量.

Effects of waterlogging on the growth and energy-metabolic enzyme activities of different tree species

Aimed to understand the watedogging tolerance and adaptation mechanisms of different tree species,a simulated field experiment was conducted to study the growth and energy-metabolic enzyme activities of one-year-old seedlings of Taxodium distichum,Carya illinoensis,and Sapium sebiferum.Three treatments were installed,i.e.,CK,watedogging,and flooding,with the treatment duration being 60 days.Under waterlogging and flooding,the relative growth of test tree species was in the order of T.distichum > C.illinoensis > S.sebiferum,indicating that T.distichum had the strongest tolerance against waterlogging and flooding,while S.sebiferum had the weakest one.Also under watedogging and flooding,the root/crown ratio of the three tree species increased significantly,suggesting that more photosynthates were allocated in roots,and the lactate dehydrogenase(LDH)and alcohol dehydrogenase(ADH)activities of the tree species also had a significant increase.Among the test tree species,T.distichum had the lowest increment of LDH and ADH activities under watedogging and flooding,but the increment could maintain at a higher level in the treatment duration,while for C.illinoensis and S.sebiferum,the increment was larger during the initial and medium period,but declined rapidly during the later period of treatment.The malate dehydrogenase(MDH),phosphohexose(HPI),and glueose-6-phosphate dehydrogenase(G6PDH)-6-phosphogluconate dehydrogenase(6PGDH)activities of the tree species under waterlogging and flooding had a significant decrease,and the decrement was the largest for T.distichum,being 35.6% for MDH,21.0% for HPI,and 22.7% for G6PDH-6PGDH under flooding.It was suggested that under waterlogging and flooding,the tree species with strong waterlogging tolerance had a higher ability to maintain energy-metabolic balance,and thus,its growth could be maintained at a certain level.