The Effects Of Radiation On The Incidence Of Tomato Blotchy Ripening Fruit

Blotchy ripening is an important physiological disease of tomato fruit. In this article, we study the effect of light on the incidence of blotchy ripening fruit with a susceptive variety - JiaFenlO in the low level of potassium. We investigate the incidence of blotchy ripening fruit in different shading periods, different levels of light shading intensity and in condition of the alternating of the light. The growth-development and physiological-biochemical metabolism changes of plant in different treatments are researched and the differences of normal and blotchy ripening fruit was compared in order to study the probable mechanism of the blotchy ripening fruit.The results show that when fruit in the period of white-mature, shading can greatly increase the yields of blotchy ripening fruit, and incidence, average index and severity index of blotchy ripening fruit are also ascended significantly. While in the fruit setting period, except that average index of blotchy fruit was observably higher than no shading treatment, the incidence and severity index of blotchy ripening fruit was insignificant. So fruits in white-mature period are the sensitive period for the incidence of blotchy ripening fruit to shading.When fruits in white-mature period, the light intensity also influent the incidence of blotchy ripening fruit although the incidence is not increased with the shading level. In this research, in one-layer-gauze shading treatment (25% light degreased) , incidence, average index and severity index of blotchy ripening fruit are higher significantly than those in treatment of double-gauze shading (40% light degreased) and nonshading. The treatment of double-gauze shading also increase the blotchy ripening fruit, especially the average index. Alternating light intensity also contribute to the incidence of blotchy ripening fruit.The treatments of shading and alternating light intensity probably affect the carbon and nitrogen metabolism and the ratio of carbon/nitrogen is reduced so induce the incidence of blotchy ripening fruit. Shading in fruit setting period and56double shading depress leaf photosynthesis and photosynthate decrease. In the same time, the level of absorption and assimilation of nitrogen runs down. While shading in fruit white-mature period and single shading have little effect on photosynthate in leaf and fruit, so are absorption and assimilation of nitrogen. And in the root exudates , content and ratio of NH4+-N are both increased. The nitrogen metabolism of the plant and fruit are relatively active. As a whole, the reason of high blotchy ripening fruit incidence in treatment of shading in fruit white-mature period and single shading maybe the decrease of carbon/nitrogen ratio.Comparison normal and blotchy ripening fruit, we can see the ethylene releasing in pericarp varies widely. In the blotchy ripening fruit pericarp, especially the green pericarp have low ethylene level which perhaps is the main reason for the green pericarp can't soften normally. The low level of ethylene releasing can influence other factors with accelerating ripening function.In the green pericarp of blotchy ripening fruit, the content of fructose and glucose is greatly lower contrasted with its red pericarp and normal fruit pericarp. But the contents of NCV-N and NH4+-N, especially the latter, are noticeably accumulate. In the normal pericarp the NH4+-N content is so little that almost can't be mensurated.'In blotchy ripening fruit the assimilation of NH4+-N maybe restrained by the shortage of carbon skeletons. The content of amino acid decreased sharply, and the Gin content is more evident. The ratio of N/C in blotchy ripening fruit pericarp is higher than that in normal fruit. The carbon and nitrogen metabolism are turbulent and brown substance accumulated.In the brown vascular and green pericarp of blotchy ripening fruit, there are more phenols matter which is an important factor in causing browning. We consider that the phenols matter is also a main matter accumulating in the browning tissue of blot...