凋落叶对樟子松幼苗生长和生理特性的影响

Effects of litter on growth and physiological properties of Pinus sylvestris var.mongolica seedlings

为了探究樟子松凋落叶是否存在抑制其幼苗生长的物质,了解樟子松人工林内幼苗存活障碍,明确樟子松凋落叶及其水浸液对幼苗生理特性和生长的影响。本试验采用盆栽法培养樟子松幼苗,分别设置浓度为12.0、6.0、3.0、1.5 g·L^(-1)的樟子松凋落叶水浸液处理和4.30、2.15、1.08、0.54 kg·m^(-2)的凋落叶覆盖处理。结果表明:(1)3.0 g·L^(-1)凋落叶水浸液处理和2.15 kg·m^(-2)凋落叶覆盖促进幼苗生长,化感综合效应指数(M r)为0.10和0.17;(2)12.0 g·L^(-1)凋落叶水浸液处理和0.54 kg·m^(-2)凋落叶覆盖处理分别使幼苗叶丙二醛含量显著(P<0.05)升高37.48%和88.15%;(3)所有处理较CK均抑制了幼苗叶光合色素含量,降幅为17.6%~49.6%;均提高了幼苗叶可溶性蛋白含量,增幅为0~23.14%;均提高了幼苗根过氧化物酶活性,增幅达149.76%~1887.13%;(4)6.0 g·L^(-1)凋落叶水浸液和2.15 kg·m^(-2)凋落叶覆盖处理对幼苗生理指标促进效果最强,M r分别为0.39和0.12。综上,樟子松凋落叶水浸液对樟子松幼苗生长表现出了“低促高抑”的质量浓度效应。人工林管理过程中,沙地樟子松凋落叶覆盖量维持在2.15 kg·m^(-2)左右有利于幼苗生长,低于0.54 kg·m^(-2)不利于幼苗生长。

To explore whether there were substances that inhibit seedling growth in the litter of Pinus sylvestris var.mongolica,understand the barriers to seedling survival in P.sylvestris var.mongolica plantations,clarify the effects of litter and its extract liquid on seedling physiological properties and growth of P.sylvestris var.mongolica.In this study,P.sylvestris var.mongolica seedlings were cultured in pots with different concentrations of leaf litter extract liquid,set to 12.0,6.0,3.0,and 1.5 g·L^(-1),and leaf litter cover,set to 4.30,2.15,1.08,and 0.54 kg·m^(-2).The results showed that:(1)3.0 g·L^(-1)of leaf litter extract liquid treatment and 2.15 kg·m^(-2)of leaf litter cover treatment promoted seedling growth,with the synthetical allelopathic index(M r)0.10 and 0.17,respectively;(2)the malondialdehyde content in seedling leaves was significantly(P<0.05)increased by the 12.0 g·L^(-1)leaf litter extract liquid and 0.54 kg·m^(-2)leaf litter cover treatments,which were 37.48%and 88.15%higher than that in the control,respectively;(3)compared with CK,all treatments inhibited photosynthetic pigment content in seedling leaves by 17.6%-49.6%.The soluble protein content of the seedling leaves increased by 0-23.14%.Peroxidase activity of seedling roots increased by 149.76%^(-1)887.13%;(4)6.0 g·L^(-1)of leaf litter extract liquid and 2.15 kg·m^(-2)of leaf litter cover treatment had the strongest promoting effects on seedling physiological indexes,with M r values of 0.39 and 0.12,respectively.In conclusion,the extract liquid of the leaf litter of P.sylvestris var.mongolica showed a mass concentration effect of"low concentration promotion and high concentration inhibition"on the seedling growth of P.sylvestris var.mongolica.Leaf litter cover of P.sylvestris var.mongolica in sandy land maintained at 2.15 kg·m^(-2)was conducive to seedling growth,but not at concentrations below 0.54 kg·m^(-2).