Foliar paclobutrazol application promotes photosynthetic abilities and growth performances and calcium ion levels, in salt-stressed water spinach (Ipomoea aquatica)
We investigated the effect of foliar PBZ pretreatment (0, 17 and 51 μM) on biochemical, physiological and morphological changes in water spinach (Ipomoea aquatica Forsk.) subjected to 0 or 100 mM NaCl. Node cuttings with 7-8 leaves of water spinach, Chia Tai or CT commercial cultivar (green stem) and Wild Type or WT cultivar (red stem) were used. After 14 days of salt treatment, Na+ in the leaf tissues of CT and WT cultivars was enriched when subjected to 100 mM NaCl. In contrast, Na+ in the salt-stressed plants was unaffected when sprayed with 51 mM PBZ before exposure to salt stress. In addition, Ca2+ in each organ of salt-treated plants (both CT and WT cultivars) was evidently enriched, especially in the leaf tissues of 51 μM PBZ foliar spray under salt stress condition. Net photosynthetic rate (Pn) in the second fully expanded leaf from the tip in cultivar 'CT' was maintained when exposed to 100 mM NaCl, leading to stabilizing effect on shoot height, number of leaves, shoot fresh weight and root fresh weight. In addition, Pn and growth abilities in 51 μM PBZ-pretreated plants of cultivar 'OWT' under salt stress were maintained. The study concludes that LSQUOCTRSQUO water spinach can tolerate salt stress better than 'WT' and the foliar application of 51 μM PBZ improved the salt tolerant ability in 'WT', as indicated by Pn stabilization and growth regulation.
Kitayama, M., Tisarum, R., Theerawitaya, C., Samphumphung, T., Takagaki, M., Kirdmanee, C. and Cha-um, S. (2018). Foliar paclobutrazol application promotes photosynthetic abilities and growth performances and calcium ion levels, in salt-stressed water spinach (Ipomoea aquatica). Acta Hortic. 1206, 291-298
commercial cultivar, growth characters, net photosynthetic rate, sodium ion, wild type cultivar