The Impact of Desiccation on Hormonal Imbalance Leading to Impaired Germination Percentage in the Recalcitrant Seeds of Syzygium zeylanicum (L.) DC.

Plant growth regulators (PGRs) play a ubiquitous role in seeds by controlling cellular communications in response to unanticipated environmental stimuli. This retaliation is crucial for recalcitrant seeds since they are desiccation sensitive. Understanding the desiccation tolerance level of each plant species is important, as it varies depending on different species. However relatively minimal investigation has been done on the hormonal dynamics in response to desiccation in recalcitrant seeds. One of the numerous other variables that control seed viability and germination in recalcitrant seeds is moisture content. In this context, the present study emphasizes on how desiccation related decreased moisture content can impair plant growth regulators synthesis or accumulation in the seed tissues of recalcitrant Syzygium zeylanicum. Seeds of mature, fallen, germinated and desiccated stages were chosen for the study. Our results showed that a shift in seed tissue moisture content causes different hormonal imbalance, noticeably an increased quantity of all phytohormones during germination except ABA. However, desiccation inhibited the synthesis of GA4, the hormone critical for germination, while enhanced synthesis of ABA. GA4/ABA ratio also got affected by desiccation. Jasmonates, cisJ and JA concentrations exhibited unexceptional rise during desiccation prior to seeds reach its critical moisture content might be linked to cell membrane damage since moisture content of seeds was inversely related to electrolyte leakage. Hence, desiccation considerably fluctuated the quantity of phytohormones GA4, ABA, IAA, IBA, cisJ, JA and SA, resulting in lower germination percentage.