槲皮黄素-3-α-阿拉伯糖苷胁迫对木麻黄小枝和根系渗透调节物质的影响

Influences of Quercetin-3-α-araboside on Osmolytes in Branchlets and Roots of Casuarina equisetifolia L.

苗期是木麻黄（Casuarina equisetifolia L.）生长对化感胁迫比较敏感的时期,而渗透调节是植物适应逆境胁迫的重要生理机制之一.为明晰木麻黄应对化感胁迫的抗性机理,以＂惠安1号＂木麻黄水培幼苗为实验材料,在人为控制环境条件下,研究了在木麻黄化感物质槲皮黄素-3-α-阿拉伯糖苷（Q3A）0（CK）,12.5,25,50,100,200,400mg/L质量浓度模拟胁迫下,木麻黄幼苗根系及小枝渗透调节物质0~72h的变化规律及其生理调节机制.研究结果表明：200和400mg/L质量浓度化感物质胁迫下,木麻黄幼苗小枝的有机渗透调节物质可溶性蛋白、可溶性糖、游离氨基酸和脯氨酸含量均呈现先上升后下降趋势;其余胁迫处理的有机渗透调节物质均呈现上升趋势,而且胁迫质量浓度越高,有机渗透调节物质含量上升幅度越大;根系与小枝表现类似,但小枝的渗透调节能力优于根系.低质量浓度（12.5和25mg/L）化感物质胁迫结束后72h,小枝和根系的有机渗透调节物质含量可以恢复到对照水平.100,200,400mg/L质量浓度化感物质胁迫造成无机离子显著下降.其他不同程度的化感物质胁迫后,小枝和根系中的无机离子K＋、Mg2＋、Ca2＋等含量轻微下降或变化不大.上述研究结果表明：木麻黄幼苗在经受低质量浓度和短期化感物质胁迫下能够有效地进行渗透调节,而且有机渗透调节物质对化感物质胁迫的反应较无机离子更为敏感.本研究结果可为筛选抗自毒木麻黄无性系提供实验依据.

Allelochemical stress is one of the most important ecological factors affecting the growth of Casuarina equisetifolia L.,and plants adapt to stress using different strategies at different growth stages.Osmolyte accumulation is frequently viewed as a key mechanism responsible for plant′s tolerance to stress.A great deal of studies show that C.equisetifoliais very sensitive to allelochemical stress during the seedling stage.In order to investigate the resistance of C.equisetifoliato allelochemical stress,clones of＇Huian No.1＇C.equisetifolia were hydroponically cultivated to study the effects of osmolyte in branchlets and roots under allelochemical stress（of seven concentrations：0,12.5,25,50,100,200 and 400mg/L）induced by quercetin-3-α-araboside（Q3A）for 0-72 h.The results showed that with prolonging of treatment time,organic osmdytes in branchlets increased significantly in various allelochemical stress treatments with the exception of two treatments,in which organic osmolytes including soluble sugar,soluble protein,proline and free amino acid in branchlets showed the trend of increasing firstly and then decreasing by 200 and 400 mg/L Q3 A stress.The organic osmotic-regulated matter increased rapidly with increasing severity of Q3 Astress.Moreover,osmotic adjustment in root was positively correlated to that in branchlet,but the root was more sensitive to Q3 Astress than the branchlet.Organic osmolytes content in branchlets and roots could return to the normal level after 72 hat the end of slight Q3Astress（12.5,25mg/L）.Inorganic osmolytes including K＋,Ca2＋and Mg2＋showed no significant changes after Q3 Astress treatment,except for those under severe stress treatment（100,200 and 400 mg/L）.The results suggest that C.equisetifolia seedling could effectively maintain its physiological equilibrium by adjusting itself to slight Q3 Astress condition and the organic osmotic-regulated matter responds to Q3 A stress more sensitively than the inorganic ions at seedling stage.This study can provide practical guidance for screening anti-autotoxicity C.equisetifoliaclones.