Plant Growth Regulators Affecting Leaf Traits of Loquat Seedling

Leaf is a key functional traits that shows respond of changes in plant physiology. This experiment aimed to study the changes on the leaf traits of loquat seedling that treated with plant growth regulators (PGRs). Three types of PGRs, auxin (naphthalene acetic acid/NAA), gibberellin (gibberellic acid/GA3) and cytokinin (benzylaminopurine/BA) with four doses (0, 25, 50, 100 ppm) were sprayed onto the leaves of loquat seedling. We observed nine parameters, PGRs treatments were significantly affecting eight parameters, while there were one parameter is not significantly affected. The results showed that either in mature or young leaves, PGRs treatments were significantly affecting in eight parameters the growth and development of leaves, such as leaf surface area, specific leaf area, fresh and dry weight leaf, water content, number of stomata, size of stomata, chlorophyll and transpiration rate compared to control. These results gave general view that PGRs treatment might stimulate leaf growth and development including photosynthesis and respiration. However, PGRs was not significantly affecting the number of stomata in young leaves. The application of PGRs doses was not always inline with the mean value of each parameters and it could be linear or quadratic models. The findings of this research could provide the recommendation for application of PGRs during seedling growth, and theoretical basis for comparison between mature and young leaves after PGRs application.