Physiological Responses of Safflower (Carthamus tinctorius) to Osmotic Stress

To screenthe related osmotic tolerance indexes and osmotic-tolerant Carthamus tinctorius L.genotypes growing in Sichuan Province of China, the germination rate (GR), germination index (GI), germination potential (GP), germination osmotic resistance index (GORI), contents ofosmotic-adjustment products, malondialdehyde (MDA) and antioxidant enzymes activities (SOD, CAT and POD) of 14 accessions of safflowerwere studied by simulated soil osmotic with 20% PEG-6000 solution. Principal component analysis and fuzzy subordinate function analysis were used for comprehensive evaluation of osmotic resistance in germination period. Meanwhile, multiple indexes of osmotic resistance of safflower were identified and screened. The results showed that there were significant differences among all the 14 genotypes and their interaction (P < 0.05) for all tested parameters. The relative values of GR, GP, GI, GORI and SOD activities were significantly positively correlated with osmotic resistance of C. tinctorius which could be used as the screening index of osmotic resistance identification. Principal component analysis was conducted on GR, GI, GP, GORI, contents of osmotic-adjustment products, MDA and antioxidant enzymes activities, and 5 principal components were obtained whose accumulated contribution rate was 92.75%. Totally, GR, GP, GI, GORI and SOD activity could be taken as primarily comprehensive indexes of osmotic resistance in C. tinctorius plants. The analysis of principal component and comprehensive subordinate function showed that 14 accessions of safflower were divided into different osmotic tolerant levels. PI401470 (No.12), PI401477 (No.16), PI470942 (No.23) and PI544021 (No.28) were identified as highly osmotic resistant cultivars. (C) 2019 Friends Science Publishers