棉花苗期叶片关键生理指标对涝渍胁迫的响应

Dynamic Responses of Main Physiological Indices in Cotton Leaf to Waterlogging Stress at Seedling Stage

利用盆栽棉花幼苗进行不同时长(3、6、9、12d)的淹水试验,观测棉花叶片的叶绿素组分(Chl)、叶色度(Rc)、叶绿素荧光动力学参数(F0、Fm)、丙二醛(MDA)、可溶性糖(DS)、脯氨酸(Pro)、超氧化物歧化酶(SOD)、过氧化物酶(POD)等关键生理指标,并与对照进行比较,分析其对涝渍灾害的响应。结果表明,淹水后的前3d棉苗叶片叶绿素水解速度最快,叶绿素荧光活性下降的峰值则出现在淹水后第6～9天。说明在田间管理上,应抓住时机在棉田淹水后的3d内尽快排涝降渍,避免植株光合能力受强烈抑制。涝渍胁迫发生后,叶片细胞内代谢平衡被打破,产生了如MDA含量增加和SOD活性下降等负面变化,不利于植株的恢复,同时也产生了如DS、Pro含量增加和POD活性提高等一系列正面变化,这对活性组织有保护作用。在淹水12d内,这些生理指标的变化速率呈现快-慢-快的规律,可用三次曲线来模拟其变化特点。

Based on cotton flooding experiment of different duration through pot culture in seeding stage, a series of physiological indices in leaf, such as chlorophyll content （Chl）, chlorophyll relative value （Rc）, chlorophyll fluorescence （ F0, Fm ）, malondialdehyde （ MDA）, nomadic proline （Pro） , dissoluble sugar （DS） , peroxidase （ POD ） and superoxidc dismutase （SOD） , were observed, to analyze the responses to waterlogging stress. The results indicated that, after waterlogging, chlorophyll hydrolysis rate was higher at the first 3 days, the peak value of chlorophyll fluorescence decrease occurred between the 6th to 9th day. It figured that stagnant water on the field should be drain off in 3 days after waterlogging stress, to avoid the photosynthetic efficiency being strongly inhibited. The balance of normal physiological metabolic process in cotton leaf was broken after waterlogging, some new negative changes occurred, as MDA content increasing and the activity of SOD decline. Some other positive changes were accompanied, as the increasing of DS and Pro content and the activity of POD, for protecting active tissues. These physiological indices appeared regularly changing characterized by fast - slow - fast, which can be simulated in unary cubic regression curve model.