不同抚育措施对衰老火炬树叶片生理的影响

通过探讨除萌蘖、修剪、断根3种抚育措施处理对12年生衰老火炬树生理特性的影响,探究其衰老机理。设置4组处理,CK为对照组,D1为除萌蘖处理组,将主树2 m范围内萌蘖苗全部剪除,之后每隔15 d将新萌蘖苗剪除;D2为修剪处理组,将冗杂枝、干枯枝、过密枝疏除,树冠回缩;D3为断根处理组,距树干50 cm处画圆,沿弧线分6段,每隔1段断根处理,共断1/2的根。于6月开始取成熟叶片为试验材料,之后每隔30 d取样1次,测定各处理下叶片的生理指标变化规律。结果表明,在除萌蘖、修剪、断根3种抚育措施处理下,火炬树叶片叶绿素含量、SOD、POD、CAT活性、可溶性蛋白含量呈现 “先升高后降低”的变化趋势,最高值分别较CK显著增长44.78%、22.10%、73.27%、141.31%、39.05%,可溶性糖含量呈现“升高”趋势,MDA含量呈现“先降低后升高”趋势,最低值显著低于CK 25.20%。3种抚育措施处理对火炬树早期预防衰老以及衰老期改善生长状态、延缓火炬树衰老均有明显作用,各处理综合评价结果为除萌蘖处理对衰老火炬树叶片生理影响效果最好,断根处理次之,修剪处理影响效果最差。

Effects of Different Tending Measures on Physiology of Senescent Rhus typhina Leaves

Rhus typhina is an excellent ornamental tree species with colorful leaves,but its short life has affected its ornamental value.The physiological characteristics of 12-year-old aging R.typhina were studied through three tending measures,including sprouting,pruning and root cutting,and its aging mechanism was explored.Four groups of treatments were set up in the experiment,the group without any treatment was taken as the control.D1 was the sprouting treatment group,all sprouting seedlings within 2 m of the main tree were cut off,and then new sprouting seedlings were cut off every 15 days.D2 was the pruning treatment group,in which redundant branches,dry branches and over-dense branches were removed and the crown was retracted.D3 was the root cutting treatment group,in which a 50 cm circle was drawn away from the trunk and six sections were divided along the arc.The root cutting treatment was carried out every other section,and a total of 1/2 roots were cut off.Mature leaves were taken as experimental materials in June,and then sampled every 30 days to measure the changes of physiological indexes of the leaves under different treatments.The results showed that the chlorophyll content,SOD,POD,CAT activities and soluble protein content in the leaves of R.typhina showed a trend of “first increasing and then decreasing”,and the highest values significantly increased by 44.78%,22.10%,73.27%,141.31% and 39.05% compared with the control,respectively.Three kinds of tending measures had obvious effects on preventing the early senescence of R.typhina,on improving the growth state and delaying the senescence of the tree during the senescence period.The comprehensive evaluation results of all treatments showed that the treatment of removing sprouting tillers had the best effect on the physiology of aging R.typhina leaves,followed by root cutting treatment,while the pruning treatment had the worst effect.