Changes Of The Carotenoids Content And The Relationship With Chlorophyll Fluorescence Parameters In Pepper Leaves Under Low Temperature With Poor Light

The purpose of this project was to study changes of carotenoids contents and analysis its relationship with the chlorophyll fluorescence parameters in pepper plants to understand their relationship in tolerance to low temperature and poor light. This project used intelligent artificial climate chambers, simulating low light(28℃/18℃, 100μmol·m-2·s-1) and low temperature with poor light(15℃/5℃,100μmol·m-2·s-1) to simulate circumstance of sunlight in greenhouse during deep winter. Pepper seedlings(Capsicum annuum L.)of two cultivars “Longjiao No.5”and “Xiangyan No.16” were selected as test material, in the processing of 0, 5, 10, 15, 20 d, by the method of R-HPLC to determinate of neoxanthin, vioxanthin, lutein, zeaxanthin, β- carotene content, meanwhile using FMS-2 pulse modulated fluorometer measure chlorophyll fluorescence parameter in Pepper leaves dynamically.1. The content of 5 carotenoids in “Longjiao No.5”and “Xiangyan No.16” Pepper leaves was that, lutein> β- carotene> violaxthin> neoxanthin> zeaxanthin. In “Longjiao No.5” the content of each carotennoids were189.45, 50.03, 22.35, 16.52, 5.04 ug/g,while in “Xiangyan No.16” were189.45, 50.03, 22.35, 16.52, 5.04 ug/g。Both for “Longjiao No.5” and “Xiangyan No.16”, Lutein content can reach up to 36-38 percent of the total carotenoids content, β- carotene account for 9%-10%, violaxthin of total carotenoids 4-5%, neoxanthin of 3-4%, lower in proportion of zeaxanthin, rarely about 1%.2. Study variation of 5 main types of carotenoids content so as to make it clear that how each component responding to poor light or low temperature and poor light respectively.The results showed that: under low light with the extension of the processing time in “Longjiao No.5” the content of neoxanthin and Violaxthin increased,after the first increase in lutein content then decreased, zeaxanthin content decreased, β- carotene content did not change significantly. In “Xiangyan No.16” Neoxanthin, violaxthin, lutein, β- carotene content increased at first and then decreased, zeaxanthin levels continue to drop. When under the low temperature and poor light, in “Longjiao No.5” Neoxanthin, violaxthin content decreased, zeaxanthin and lutein continuing to rise, β- carotene basically unchanged. In “Xiangyan No.16” Neoxanthin, violaxthin, β- carotene content decreased, zeaxanthin and lutein content increased, and its increased rate significantly lower than that of “Longjiao No.5”.3. Changes in chlorophyll fluorescence parameters were measured. Results showed that both in Longjiao No.5 and Xiangyan No.16 PSⅡ potential activity was inhibited under the low light and low temperature and poor light the fommer has a greater influence.With the processing time prolong, the absorption of light energy for photochemical part(P) decreased, while the part of the antenna heat dissipation(D) increased, PSⅡ dissipative part of the non-photochemical reaction center(Ex) is also increasing. Correlation analysis of carotenoids content and chlorophyll fluorescence parameters found that there is no correlation between Neoxanthin, β- carotene and Fv/Fm、ΦPSⅡ、Fv′/Fm′、qP、NPQ 、Fs 、Fm′、Fo′、Fv′. Violaxthin and ΦPSⅡ was a significant positively related, lutein and qP a significant negative related, but it is a significant relevant with the NPQ. zeaxanthin also a significant negative relevant to qP,(r2=-0.507,)and a significant related to the NPQ(r2=0.706).