保存光强对耐干藓生理特性与营养繁殖的影响

Effects of light intensity on physiological characteristics and regenerative capacity of desiccation-tolerant mosses after air-dry storage

【目的】研究不同保存光强对耐干藓生理特性与营养繁殖的影响,为耐干藓营养繁殖及人工培养提供理论依据。【方法】以黄土丘陵区常见3种耐干藓优势种(扭口藓、土生对齿藓、短叶对齿藓)为材料,在0 lx(遮光,L0)、20 lx(避光,L1)、4 000 lx(温室,L2)下以干燥状态保存89 d,测定保存前后配子体生理指标(叶绿素、可溶性糖、可溶性蛋白质、丙二醛含量)与萌发参数(配子体萌发率、配子体增加量、配子体活力指数),研究不同保存光强对耐干藓生理特性与营养繁殖的影响。【结果】除了土生对齿藓和短叶对齿藓的叶绿素含量以及短叶对齿藓L0、L2处理的可溶性糖含量外,不同光照处理的3个藓种的不同生理指标均高于保存前。随着光强的增加,土生对齿藓和短叶对齿藓的叶绿素含量总体均呈现下降的趋势,扭口藓叶绿素含量则先增加后下降;扭口藓可溶性糖含量下降,土生对齿藓可溶性糖含量无显著变化,短叶对齿藓可溶性糖含量先增加后下降;扭口藓和土生对齿藓的可溶性蛋白质含量增大,短叶对齿藓的可溶性蛋白质含量则先增加后下降;扭口藓和短叶对齿藓的丙二醛含量先增后减,土生对齿藓的丙二醛含量呈现先下降后增加的趋势。随着光强的增加,扭口藓萌发参数均呈增加的趋势,土生对齿藓的萌发参数变化均不显著,短叶对齿藓的萌发参数均呈降低趋势。叶绿素含量与配子体萌发率存在显著正相关(P<0.05),可溶性蛋白质含量则与配子体萌发率存在极显著正相关(P<0.01),可溶性糖含量与配子体增加量有极显著负相关关系(P<0.01)。可知叶绿素、可溶性糖、可溶性蛋白质含量变化对藓类复水后的营养繁殖结果影响较大。【结论】长期干燥期间,光强影响藓类细胞膜渗透性,使其生理特性与营养繁殖能力发生明显变化。不同耐干藓适宜的保存光强存在差异。

【Objective】 This study investigated the effects of different light intensities on physiological characteristics and vegetative propagation of desiccation-tolerant mosses after storage to provide theoretical foundation for vegetative propagation and artificial cultivation of desiccation-tolerant mosses.【Method】 Three dominant species of common desiccation-tolerant mosses in the Loess hilly region of China,including Barbula unguiculata,Didymodon vinealis and Didymodon tectorum,were collected and stored at three light intensity gradients in a dry environment for 89 days.The three light intensity gradients were 0 lx(shading,L0),20 lx(away from light,L0) and 4 000 lx(in greenhouse,L2).The physiological indices(contents of chlorophyll, soluble sugar,soluble protein and malondialdehyde) and germination parameters(gametophyte germination percentage,gametophyte increment and gametophyte vigor index) of moss gametophytes were investigated before and after storage to determine the effects of different light intensities on the physiological characteristics and vegetative propagation of desiccation-tolerant mosses after storage.【Result】 Except for chlorophyll contents of D.vinealis and D.tectorum and soluble sugar contents of D.tectorum in L0 and L2 treatments,all physiological indices of the three mosses at each light intensity after storage were higher than before storage.When light intensity increased, chlorophyll contents of D. vinealis and D. tectorum generally decreased,while contents of B. unguiculata increased at first and decreased thereafter. The soluble sugar content of B.unguiculata decreased with increasing light intensity, while content of D. tectorum increased at first and then decreased.The soluble sugar content of D. vinealis showed no significant difference among light intensities.The soluble protein content of B.unguiculata and D.tectorum continuously increased when the light intensity increased,while that of D.tectorum increased at first followed by decrease.The malondialdehyde contents of B.unguiculata and D.tectorum increased firstly and then decreased with increasing light intensity, whereas that of D.vinealis had an opposite trend.When light intensity increased,the germination parameters of B.unguiculata increased,while that of D.tectorum decreased.There were no significant differences in germination parameters among the light intensities in D.vinealis.Gametophyte germination percentage was significantly positively correlated with chlorophyll content(P<0.05) and soluble protein content(P<0.01),while gametophyte increment was significantly negatively correlated with soluble sugar content(P<0.01).These correlations indicate changes in contents of chlorophyll,soluble sugar and soluble protein had significant effect on vegetative propagation of mosses after rehydration.【Conclusion】 Light intensity had significant effect on membrane permeability of mosses and caused significant changes in physiological characteristics and vegetative propagation capacity of mosses during long-term dry.The adaptive storage light intensity of desiccation-tolerant mosses varied with species.