Pre Harvest Foliar Application of Methyl Jasmonate on Fruit Quality and Quality Enzymes and Phenolic Compounds Changes During Storage of Grapefruit

Grapefruit is an important fruit crop in the world as well as in Pakistan. The signalling molecule like methyl jasmonate (MeJA) are endogenous plant growth substances which can play a key role in plant growth and development and responses to environmental stresses. Phytochemicals in grapefruit are considered very important for human body due to their medicinal properties. The effects of methyl jasmonate (MeJA) applied before fifteen days of harvesting to estimate the fruit firmness, fruit color, total soluble solid (TSS), weight loss, total phenolic (TP) and separate phenolic compounds , total antioxidant activity (TAA) of “grape fruit were analyzed at initial stage of harvesting and after storage. Foliar spray of methyl jasmonate (MeJA) significantly decreased fruit weight loss after 90 days storage. Quality related parameters were maintained after 90 days storage. The higher doze of MeJA @ 4mM significantly maintained the total phenolics and antioxidant after 90 days of storage. Enzymes peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), and superoxide dismutase (SOD), Polycultrase (Poly) were found higher at 90 days storage these enzymes play an important role to developed a defense mechanisms in stored fruit those were delay fruit repining and improve shelf life of grapefruit during storage. MeJA applications has significantly increased different individual phenolic compounds especially chlorogenic acid contents after 90 days storage. These phytonutrient have significant role for antioxdative stress anti-viral, anti-cancer, anti-inflammatory activities of human body. The application of MeJA has potential to produce the different enzymes linkage which increased the fruit internal change and produce the resistance for disease resistance and improve the quality of fruits.