高羊茅腐解物的自毒作用初探

Preliminary Studies on Autotoxicity Effects of Tall Fescue( Festuca arundinacea Schreb) Decomposition Products

为探明高羊茅草坪逐年退化现象是否与化感作用有关,在室内用生物测定方法测定了高羊茅腐解物对高羊茅自身的化感作用,并探讨了相关的作用机制。结果表明,高羊茅腐解液能抑制高羊茅种子的萌发和幼苗生长,且腐解液质量浓度越大,抑制作用越明显。在腐解液质量浓度为0.06 g/m L时,其对高羊茅种子发芽率、发芽势、发芽指数、活力指数、根长、苗高、单株鲜质量的抑制率分别达58.64%、81.68%、73.34%、81.63%、37.86%、41.13%、30.43%。随着高羊茅腐解液质量浓度的增加,其幼苗SOD活性先升后降;POD活性与空白对照差异不显著;CAT活性先升后降,在高质量浓度时,与空白对照的差异达到显著水平;膜脂过氧化产物MDA含量持续升高;可溶性蛋白含量下降。可见,高羊茅残体腐解是其草坪逐年退化的原因之一。

The allelopathic autotoxicity effect of the decomposed liquid of tall fescue on its seed germina-tion and seedling growth was tested in laboratory by adopting indoor bioassay,aiming to approach whether the allelopathic autotoxicity effect exists in the degradation of tall fescue lawn year by year. The results showed that,the decomposed liquid of tall fescue remarkably inhibited the germination of tall fescue seed and the growth of tall fescue seedlings,and the inhibition effect became stronger as the concentration of the decomposed liquid increased. At 0. 06 g/mL of the decomposed liquid,the germination rate,germina-tion energy,germination index,vigor index,root length,seedling height,single plant weight were reduced by 58. 64%,81. 68%,73. 34%,81. 63%,37. 86%,41. 13%,30. 43%,respectively. With the concentra-tion of the decomposed liquid increased,the activity of SOD in vivo first increased and then decreased, while the activity of POD showed no significant difference with the control. The activity of CAT first in-creased and then decreased, and had significant difference with the control when the concentration of the decomposed liquid was 0. 06 g/mL. And the decomposed liquid of tall fescue increased the content of MDA,and decreased the content of soluble protein. We conclude that decomposition of tall fescue residue is one of the reasons why the tall fescue lawn degrades year by year.