Authors: Rajni Sinha, Anugya kumari
Department of horticulture (Fruit and Fruit Tech.)B.A.U., Sabour, Bhagalpur, Bihar,India,813210
*E-mail: rajnisinha19h@gmail.com
Introduction
Although there are various important regulating roles displayed by gaseous phytohormone ethylene in many plant physiological processes such as seed germination, root initiation, abscission, senescence, wounding and climacteric fruit ripening. Among them, it has been studied that the most prominent effect on ripening of harvested produce. These effects can be beneficial or harmful depending on the nature of produce, its ripening stage, and its desired use . Endogenous ethylene production is an essential part of ripening of climacteric fruit but it is avoidable during long storage purpose. In this context, a stimulating new strategy for controlling ethylene production and its effect on ripening and senescence of fruit and vegetable has emerged with the invention and commercialization of the inhibitor of ethylene perception, 1-methylcyclopropene (1-MCP) (Sisler and Serek., 2003). 1-MCP is most potent gaseous inhibitor that acts against ethylene amongst rest of organic olefins by blocking ethylene perception and preventing ethylene effects in plant tissues for extended periods leads to delay in fruit ripening and improves storage quality of climacteric fruits . 1-MCP is synthetic cyclopropenes that binds to the ethylene receptor with 10 times more affinity than ethylene itself, and become more active at much lower concentrations (20 nl l−1 to 40 μl l−1).The impact of 1-MCP on postharvest science and technology has been two-fold for maintaining the postharvest quality of many fresh commodities, both climacteric and non-climacterics. First, it maintain fruit and vegetable quality after harvest. Second, 1-MCP provides a powerful tool to gain insight into the fundamental processes that are involved in ripening and senescences. Moreover, this compound is universally accepted worldwide due to nontoxiness to humans and environment and leaves negligible residue. Presently, 1-MCP is being commercially used in cut flowers and fruit such as avocado, grapefruit, apples, bananas, melons, tomatoes and many other vegetables .It is marketted under the trade name of HarvistaTM /smartfreshTM/agrofresh and applied as either powder form or sprayable formulation of 250 μL/L 1-MCP and 1% oil adjuvant. This sprayable formulation emerge as a new tool in overall orchard management in order to overcome ethylene-dependent preharvest problems (eg, abscission), while providing for better postharvest fruit quality, storability and many effecta simultaneously which has been explained in table 1.
Inhibitory action
1-MCP inhibits the biosynthesis of ethylene by reducing the activity of the enzymes carboxylic acid synthetase (ACC synthase) and carboxylic acid oxidase (ACC oxidase). It also block ethylene production directly at genetic level by delaying MdACS1 gene expression and stimulating the expression of the MdACS3 gene thus delays ripening (Zhu et al., 2008).In spite of this, it also act on α- and β-galactosidase as well as pectin methyl esterase enzyme(PME) that is responsible for fruit softening under the commencement of ethylene evolution. Therefore, this softening can be prevented or delayed by the use of 1-MCP.Moreover,due to unstability of 1-MCP ,it react with reactive oxygen species (ROS) therefore, preventing α-farnesene oxidation and control. In addition,it delays in breakdown in skin colour pigmentation and improves quality interm of titrable acidity and total soluble solid that lead to increase in marketability of produces. Moreover, it has been found that it makes plant tolerant during stresses.
Table 1:Generalizations regarding the effects of 1-MCP on metabolism of fruit and vegetables
Source : Watkins.,2006
About Author / Additional Info:
Persuing Ph.D at Bihar Agricultural Univarsity,Sabour,Bhagalpur