土壤水分对异株荨麻(Urtica dioica)保护酶和渗透调节物质的影响及其与叶片光合和生物量的相关性

Soil water influences on protective enzymes and osmolytes of Urtica dioica and their correlations with leaf photosynthesis and biomass

通过对不同土壤水分处理下异株荨麻保护酶系(SOD、POD)活性、渗透调节物质(可溶性蛋白、可溶性糖和游离脯氨酸)和细胞膜脂过氧化产物(MDA)含量以及最大光合速率、生物量的测定,各项生理指标间线性相关性的分析,探讨异株荨麻对水分变化的响应特性和耐干旱适应能力。实验采用盆栽水分梯度法将异株荨麻扦插苗按土壤相对含水量93.58%、80.74%、67.90%、55.06%和42.22%分组,以充足水分93.58%为CK对照组,实验组水分由高到低为T1、T2、T3和T4共5组。结果表明,(1)异株荨麻体内SOD活性随水分含量下降而呈先上升后下降的变化趋势,POD活性与之成相似互补的变化趋势;可溶性蛋白、可溶性糖、游离脯氨酸和MDA含量随水分含量的下降而升高;(2)各保护酶系和渗透调节物质与土壤水分呈显著线性负相关,保护酶系、渗透调节物质与过氧化产物MDA线性正相关;(3)比较光合速率、生物量和各种酶系、渗透调节物质的关系发现,光合速率与各生理指标无明显相关性,渗透调节物质对生物量积累有显著负相关性。

The responsive ability and drought resistance of Urtica dioica seedlings under different soil water conditions were discussed in our study. The following bioassay parameters were investigated： the protective enzyme activity （SOD, POD）, accumulations of osmolyte （soluble protein content, soluble carbohydrate content, free porline content）, membrane lipid peroxidation （MDA）, max photosynthesis rate and total dry tissue weight. The linear correlations of above-mentioned physiological indexes were analyzed. The seedlings of Urtica dioica were planted at 5 different soil water gradients of 9358% （control）, 80.74%（T1）, 67.90%（T2）, 55.06%（T3） and 42.22%（T4）, respectively. Our results indicated that （1） The activity of SOD enhanced with the decrease in soil water at the start, and then depressed when the soil became too dry, while the activity of POD increased all along with the decrease in soil water. The contents of soluble protein, soluble carbohydrate, free porline and MDA increased with the decrease in soil water. （2） The protective enzyme system and accumulations of osmolyte with respect to soil water content had significant negative linear correlation, while the protective enzyme system and accumulations of osmolyte with respect to MDA had significant positive linear correlation. （3） The accumulations of osmolyte with respect to total dry tissue weight had significant negative linear correlation, while there was no significant correlation between photosynthesis rate and other physiologic index.