甲哌鎓对棉花叶片光合生理及蜡质含量的影响

为探究甲哌鎓对棉花表皮蜡质沉积及光合生理的影响，以‘新陆早55号’棉花为试材，将甲哌鎓按有效成分0、4.5、7.5、10.5和15.0 g/hm2的剂量分别喷施于叶面，于施药后1、4、7和12 d分别测定棉花叶片的光合速率和表皮蜡质含量及12 d内叶片的叶绿素相对含量（SPAD值）。结果表明:于叶面喷施甲哌鎓后，棉花叶片光合速率、表皮蜡质含量及SPAD值与甲哌鎓浓度、处理时间之间存在一定的依赖性。4.5与7.5 g/hm2的甲哌鎓处理可提高棉花光合速率并且持续期较长；SPAD值随处理时间的延长及甲哌鎓浓度的增加而增加，表明棉花叶片叶绿素含量随之增加及叶色加深；4.5 g/hm2甲哌鎓处理更利于棉花叶片表皮蜡质的沉积。蜡质、光合速率、SPAD值相关性分析结果显示，光合速率与蜡质、SPAD值间呈极显著正相关关系，说明蜡质的沉积及叶绿素含量增加有利于棉花叶片进行有效的光合作用，增强抗逆性。

Effects of mepiquat chloride on photosynthetic physiology and wax content of cotton leaves

The effect of plant growth regulator mepiquat chloride (1,1-dimethyl-piperidiniuchloride, DPC) on cotton epidermal wax deposition and photosynthesis were investigated using ‘Xinluzao 55’ as the sample. DPC was respectively sprayed on the foliage at the doses of the active ingredients of 0, 4.5, 7.5, 10.5 and 15.0 g/hm2. The photosynthetic rate and wax content of cotton leaves were measured at 1, 4, 7, 12 days after the treatment. The SPAD value of leaves was also tested within 12 days after the application of DPC. The result showed that after DPC was sprayed to cotton leaves, the photosynthetic rate of the cotton leaves, the wax content and the SPAD value have definite reliance on DPC concentration and the processing time. The photosynthetic rate of cotton could be improved by DPC treatment (4.5 g/hm2 or 7.5 g/hm2) and this effect could last for a long period. With the increase of the treatment time and DPC content, the SPAD value of cotton was increased, which indicated that the chlorophyll content of cotton leaves increased and leaf color deepened. The concentration of 4.5 g/hm2 was more favorable for the wax deposition of cotton leaf epidermis. The correlation analysis of photosynthetic rate, photosynthetic rate and SPAD value showed that the photosynthetic rate had a significant positive correlation with the wax and SPAD values. It illustrated that the deposition of wax and the increase of chlorophyll content were beneficial to the photosynthesis of cotton leaves and enhanced the resistance.