Effect of foliar applied triacontanol on wheat (Triticum aestivum L.) under arsenic stress: a study of changes in growth, yield and photosynthetic characteristics

In this study, changes in growth, yield and photosynthetic characteristics were assessed by foliar application of triacontanol (TRIA) in wheat (Triticum aestivum L.) varieties Anaj-2017, Ujala-2016 and AARI-2011 under arsenic (As) stress. Seeds of all three wheat varieties were sown in sand filled plastic pots. The experiment was conducted in a completely randomized design (CRD) with three replicates. All the plants were irrigated with full strength Hoagland's nutrient solution till the termination of experiment. Plants were applied with three levels of sodium arsenite (NaAsO2) i.e. 0 ppm, 50 ppm and 100 ppm and two levels of foliar treatment of triacontanol i.e. control (no spray), and TRIA 1 mu M applied. After 16 week of germination, data of all photosynthetic characteristics was collected, while yield was taken at maturity. Arsenic (50 ppm and 100 ppm) stress exerted significantly adverse effects on various growth and photosynthetic parameters i.e. shoot fresh and dry weights, total leaf area per plant, total grain yield per plant, 100 grain weight, number of seeds per plant, chlorophyll (chl.) pigments, chl. a, b chl. a/b ratio, flavonoids, anthocyanin contents, rate of photosynthesis (A), transpiration rate (E), internal CO2 concentration (C-i), water use efficiency (A/E), and stomatal conductance (g(s)). Foliar application of TRIA significantly increased growth and yield attributes, chlorophyll b, internal CO2 concentration, stomatal conductance, rate of photosynthesis, flavonoids and anthocyanin contents in all wheat varieties. Moreover, the results also indicated that 1 mu M TRIA proved to be effective in reducing the adverse effects of arsenic stress on all three wheat varieties. Of three wheat varieties, AARI-2011 is more sensitive to arsenic stress and Anaj-2017 proved to be more tolerant against arsenic stress. However, foliar application of TRIA proves to be more effective for var. AARI-2011.