Triadimefon induced physiological and ultra structural changes for moisture stress protection in Bougainvillea (Bougainvillea spectabilis Willd) at nursery stage

Abstract

Abstract: Hardwood stem cuttings of bougainvillea (Bougainvillea spectabilis Willd) consisting of two to four leaves were treated with triadimefon (triazole derivative) in the form of foliar spray at 50 ppm and 100 ppm, while the control plants were treated with water spray. The (treatment) plants were irrigated once in two days, once in four days and the control plants were irrigated daily. The experiment was conducted at the Al Maqam campus of the U.A.E. University, Al Ain. The experimental design was completely randomized with the two factors being irrigation and chemical treatment, consisting of nine treatment combinations, replicated three times. The relative water content (RWC) in both concentrations was similar, while the control plants showed high plant-water content. Photosynthetic pigments viz., Chlorophyll a, increased with increasing concentration of the chemical, while the Chlorophyll b and Total Chlorophyll showed significant differences with different treatment combinations of irrigation frequencies and triadimefon treatment. Combination of triadimefon with irrigation frequencies produced sun-type chloroplasts and increased chlorophyll accumulation. Compared with the control, the stomata from the abaxial epidermal peels in the triadimefon treated leaves were sunken, narrow and appeared partially closed. Both triadimefon treatments increased the number of trichomes compared to the leaf samples of control plants. Formation of epicuticular wax in treated plants was noticed, which was probably formed to act as a barrier against water loss. The results of the present study may add to the plant growth regulatory effects data published previously on the synthesis of photosynthetic pigments, and other growth responses conducive for protection against moisture stress.