Document Type : Original Article
Authors
1 , Department of Horticultural Sciences, Faculty of Agriculture, Lorestan University, Lorestan, Iran
2 Department of Horticultural Sciences, Faculty of Agriculture, Lorestan University, Lorestan
3 Department of Horticulture, Faculty of Agriculture, Lorestan University, Lorestan, Khorramabad
4 Department of Plant Protection, Faculty of Agriculture, Lorestan University, Lorestan, Khorramabad
Abstract
To evaluate the response of chrysanthemum (Chrysanthemum morifolium) to salinity stress and certain stress modulators, a factorial experiment was conducted based on a completely randomized design with three replications. The first factor comprised salinity stress at four levels (0, 30, 60, and 90 mM NaCl) applied through irrigation water, and the second factor consisted of five levels (control, L-glutamic acid at two concentrations of 300 and 600 mM, and bacterial inoculation with Pseudomonas putida and Curtobacterium spp. strains). The results indicated that increasing salinity stress significantly reduced photosynthesis rate, transpiration, stomatal conductance, maximum quantum efficiency of photosystem II (Fv/Fm), chlorophyll stability index, flower diameter, bud emergence time, and bud opening time, while increasing flower wilting. For instance, salinity at 60 mM caused a 38.07% and 58.9% decrease in chlorophyll stability index and flower diameter, respectively, compared to the control; however, the application of growth-promoting substances led to increases of 41.25% and 29.30%, respectively. Furthermore, increasing stress levels reduced potassium concentration and led to an increase in the sodium-to-potassium ratio in chrysanthemum leaves. The application of both bacterial types and both concentrations of L-glutamic acid significantly improved all measured traits compared to the control. At salinity levels of 0 and 30 mM, L-glutamic acid at 600 mM concentration had the greatest effect; however, at higher salinity levels (60 and 90 mM), L-glutamic acid at 300 mM concentration was more effective. It is noteworthy that no flowering occurred at the 90 mM salinity level.
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