Physiological and biochemical changes during flower development and senescence in Chrysanthemum and Gladiolus

Flowering duration and post-harvest life of flowers are dependent upon their senescence. The present investigation discerns the toppling of different physiological and biochemical parameters that shift floral bud to senescent flower. Chrysanthemum morifolium L. (Chrysanthemum) and Gladiolus grandiflora Hort. (Gladiolus) are two important crops occupying leading positions in cut flower industry. The tepals of Gladiolus and Chrysanthemum were evaluated at different developmental stages, ranging from tight bud to senescence to identify the stage to extend flowering duration on the plant or post-harvest life of flower through chemical manipulation. The physiological and biochemical parameters, viz., membrane stability index, relative water content, total soluble sugars, proteins, and phenols increased during initial stages of development and then decreased towards later stages. The flower colour is dependent upon the pigments, viz., anthocyanins and carotenoids that also increased from early developmental stages to fully open stage, but declined towards senescence. The increase in content of metabolites during earlier stages of flower development or flower opening indicated that developing flowers act as a sink for photo assimilates, but towards maturity, they act as a source and transfer its metabolites to developing parts of the plant. Thus, the pattern of metabolites depicted that chemical manipulation through plant growth substances could be done at loose bud stage or partially opened flowers in Chrysanthemum and colour break stage or half opened floret in Gladiolus that could delay senescence and improve their post-harvest performance.