Regulation of nitric oxide to Capsicum under lower light intensities

Capsicum is one of the main vegetables of facility cultivation in winter and spring in many places of the world. The lower light intensities formed in the facility seriously affects the normal growth and development of pepper plants. Therefore, it has important application value to carry out the regulation of pepper plant growth under lower light intensities. To reduce the adverse effects of lower light intensities on the growth of pepper seedlings (Capsicum annuum L.), Capsicum species (WM-1) were used as test materials. Growth related indicators of C. annuum plants under different light intensities were tested after spraying sodium nitroprusside (SNP, a NO donor). The results showed that nitric oxide (NO) increased significantly the plant height, stem diameter, number of branches and leaf area of plants under lower light intensities; at the same time, it also increased the activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) in pepper seedlings; NO-scavenger c-PTIO, under low light stress, the NR inhibitor tungstate and NOS inhibitor L-NAME inhibited the activity of the antioxidant system; however, their harmful effects on growth, antioxidant system could be reversed by the addition of SNP; in addition to this, NO also increased chlorophyll a, chlorophyll b, and chlorophyll (a+b) synthesis, decrease the chlorophyll a/b ratio, and generally enhance the expression level of chlorophyll synthesis genes (HEMA1, CAO and GGPS2). This indicated that NO can alleviate the adverse effects of lower light intensities for pepper growth and improve the photosynthetic performance of pepper leaves in lower light intensities conditions. (c) 2020 SAAB. Published by Elsevier B.V. All rights reserved.