基于红外热图像的棉花花铃期水分胁迫指数与光合参数的关系

目的]分析棉花冠层水分胁迫指数(CWSI)与光合参数的相关关系,建立CWSI与光合参数的相关模型,为CWS1用于定量监测新疆棉花冠层水分胁迫状况的研究提供依据.方法]在棉花生长的花铃期,利用Fluke热像仪获取2个棉花品种4水平水分处理冠层的红外热图像,运用图像处理技术,提取棉花冠层受光叶片的温度,并将湿人工参考表面(WARS)的温度运用到Jones定义的作物水分胁迫指数(CWSI)的经验公式中,计算CWSI;同时,采用LI-6400便携式光合仪测得棉花叶片净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr),并探索棉花水分胁迫指数与其光合参数的定量关系.结果]水分胁迫下CWSI值升高,而Pn、Gs和Tr值相应降低.花铃期的4个关键生育时期CWSI分别与Pn、Gs和Tr呈极显著的线性负相关关系,CWSI与Pn、Gs和Tr的平均相关系数分别为rCWSI-Pn=-0.8823**、rCWSI-GS=-0.9073**和rCWSI-Tr,=-0.9356**.结论]棉花水分胁迫指数CWSI与光合参数Pn、Gs和Tr同步反映棉花冠层的水分状况.

Correlation between CWSI from Infrared Thermography and Photosynthetic Parameters during Flowering and Boll-Forming Stage of Cotton

【Objective】Analysis of correlation between cotton water stress index canopy CWSI and photosynthetic parameters,established the linear regression model function between CWSI and photosynthetic parameters,it provided a potential tool for monitoring cotton water-stressed status by using CWSI in Xinjiang.【Method】Using Fluke infrared thermal camera obtained canopy infrared thermal images at flowering and boll-forming stage of cotton in an experimental field including two cotton cultivars with four levels water treatments.Application of the image processing technology,to acquire temperature of canopy sunlit leaves,and add wet artificial reference surface(WARS) temperature to empirical formulation which defined by Jones,calculation of CWSI,and simultaneously using LI-6400 portable photosynthesis system obtained the net Photosynthetic Rate(Pn),Stomatal Conductance(Gs) and Transpiration Rate(Tr) of cotton.And explore the quantitative relationship between cotton CWSI and photosynthetic parameters.【Result】It showed that cotton CWSI increased with water-stressed and correspondingly Pn,Gs and Tr reduced,four key growth periods of flowering and boll-forming stage of cotton,CWSI were negatively correlated with Pn,Gs and Tr,the average of the correlation coefficient of CWSI between Pn,Gs and Tr were rCWSI-Pn=-0.882 3**,rCWSI-Gs=-0.907 3**and rCWSI-Tr=-0.935 6**respectively during flowering and boll-forming stage of cotton under different level water treatments.【Conclusion】Cotton CWSI and photosynthetic parameters Pn,Gs and Tr can simultaneously reflect the water status during the flowering and boll-forming stage of cotton.