低磷胁迫对麻竹幼苗叶片非结构性碳水化合物及抗氧化保护酶系统的影响

Effects of low phosphorus stress on non-structural carbohydrates and the antioxidant protective enzyme system in leaves of Dendrocalamus latiflorus seedlings

【目的】通过研究磷胁迫下麻竹幼苗叶片的生理变化探究麻竹幼苗对低磷环境的耐受性。【方法】以麻竹幼苗为研究对象,采用水培法进行室内控制条件下的低磷胁迫试验。按照霍格兰配方配制营养液,用KH2PO4分别配制0、0.2、0.4、0.8和1.6 mmol·L^(-1)磷溶液,其他营养元素含量保持相同。【结果】麻竹幼苗叶片还原糖和可溶性糖含量随磷含量的提高而提高;淀粉、纤维素、MDA含量及抗氧化酶(CAT、POD、SOD)活性随磷含量的提高而降低。相比于缺磷处理(0 mmol·L^(-1)),磷浓度为1.6 mmol·L^(-1)时麻竹幼苗叶片的各个生理指标均呈显著差异,还原糖及纤维素含量分别上升了56.45%和67.08%,淀粉、可溶性糖、MDA含量及抗氧化酶(CAT、POD、SOD)活性分别下降了34.86%、14.61%、73.89%、64.19%、89.99%和65.34%;在不同浓度磷胁迫下MDA含量均呈显著差异,可溶性糖含量差异最小,而POD酶活性差异最大。【结论】麻竹幼苗对低磷胁迫具有较强的抗逆性,在苗期能适应低磷环境。

【Objective】The study aimed to investigate the tolerance of Dendrocalamus latiflorus seedlings to low phosphorus(P)environment by monitoring the physiological changes of leaves of D.latiflorus seedlings under different levels of P shortage.【Method】D.latiflorus seedlings were subject to low P stress by hydroponics under indoor controlled condition,with most nutrients prepared according to Hoagland formula except for P,which was set up to 5 levels of P stress(0,0.2,0.4,0.8 and 1.6 mmol·L^(-1))using KH2PO4.【Result】The contents of reducing sugar and soluble sugar in leaves of D.latiflorus seedlings were increased in response to higher P supplies,while the contents of starch,cellulose and malondialdehyde(MDA),and the activities of antioxidantenzymes[catalase(CAT),peroxide(POD)and superoxide dismutase(SOD)]were decreased.Compared with severe P depletion(0 mmol·L^(-1)),the physiological indexes of D.latiflorus seedlings under 1.6 mmol·L^(-1)P supply were significantly different,with 56.45%and 67.08%higher contents of reducing sugar and cellulose;while the contents of starch,soluble sugar and MDA,and the activities of CAT,POD and SOD were down by 34.86%,14.61%,73.89%,64.19%,89.99%and 65.34%,respectively.Among all the physiological indices,MDA contents varied significantly under different levels of P stress;the variation range of soluble sugar was the smallest,while that of POD was the greatest.【Conclusion】D.latiflorus seedlings demonstrated relatively high resistance to low P stress and was adaptable to low P environment at seedling stage.