ASPİR GENOTİPLERİNDE KURAKLIĞA DAYANIKLILIĞIN FİZYOLOJİK, BİYOKİMYASAL VE MOLEKÜLER DÜZEYDE İNCELENMESİ
Çulha Erdal, Şeküre
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In the study, it was aimed to determine the cultivars and lines of drought tolerant safflower (Carthamus tinctorius L.) and to investigate the responses of these genotypes to the drought stress with the wild safflower Carthamus oxyacantha, which is known to be resistant to drought. The study consists of 3 stages; at stage 1 (selection), 4 registered aspir cultivars and 8 lines grown in our country were screened for drought stress tolerance with recovery capacities during moderate (5 days) and severe (7 days) drought and their re-irrigation periods (5 days) using polyphasic chlorophyll a fluorescence kinetics, biochemical (ion leakage and pigment content) and physiological measurements (soil and leaf water potential with relative water content), genotypes were classified after scored data according to their tolerance rates. At stage 2 (characterization); the impact of drought (7 days) and re-irrigation conditions (5 days) on selected tolerant and sensitive genotypes and wild safflower genotypes were characterized with morphological, physiological and biochemical changes. At stage 3, changes in protein expression in safflower genotypes (tolerant; Remzibey-05 and sensitive; Linas cultivars with wild safflower) under drought conditions were explored by proteomic analysis. At selection phase, genotypes were classified as resistant to drought (Remzibey-05 and AÖVD-L/14), moderate tolerant and sensitive (Linas and AÖVD-L/12) according to the drought (KFI) and recovery factor indexes (IFI), damage indices and recovery potentials calculated according to the results obtained from some physiological and biochemical analyzes with polyphasic chlorophyll a fluorescence. Characterization results showed that the drought causes to decrease of the growth and development of the safflower genotypes. In the case of re-irrigation conditions, genotypes can recover according to their tolerance to drought. Morphological analyzes exhibited that dry weight of safflower genotypes is a more selective parameter than other parameters such as plant height, number of leaves and fresh weight in determining the effects of stress. While relative water content, photosynthetic activity and pigment content were generally unchanged in C. oxyacantha under drought conditions; the other genotypes decreased and the maximum improvement was determined in Remzibey-05. Under stress conditions the lowest membrane damage was determined in C. oxyacantha, but the highest was in Linas. It was determined that hydrogen peroxide (H2O2), proline, anthocyanin and flavonoid amount with some antioxidant enzyme activities [superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR) and peroxidase (POD)] were higher in C. oxyacantha than they were in the controls of other genotypes. H2O2 content was increased significantly in drought conditions in varieties and lines. However, the most decrease was in Remzibey-05 at rewatering. The results obtained from proline, anthocyanin and flavonoid amount and antioxidant enzyme activities [SOD, APX, GR, POD, catalase (CAT) and aldose reductase (ALR)] support these findings. In proteomic analyzes, 47 of the 72 proteins expressed differentially in the genotypes were identified using databases related to the MALDI-TOF/TOF MS/MS mass spectrometer. Most of the proteins which changed their expression under drought conditions were found to be involved in photosynthesis and carbohydrate metabolism. Changes in protein expression of genotypes were exhibited that Remzibey-05 is similar to C. oxyacantha by limiting its metabolic activities in drought, thereby reducing stress.