Study On Prohexadione Calcium On Growth Of Rice And Wheat

Prohexadione-Ca (calcium 3,5-dioxo-4-propionylcyclohexanecarboxylate) is a new plant growth regulator that inhibits the late stages of gibberellins (GAS) biosynthesis in plants, thus reducing the vegetative growth of the plant. Its negligible toxicological effects on mammals and high efficient. The specific objectives were to evaluate the effects of Prohex-Ca on growth, physiology, the root vigor, content of GAS and fruit quality characteristics of rice and wheat,when applied at different rates, and to investigate the best rate of Prohex-Ca.A field experiment with complete randomized block design was carried out at the Scientific & Educational Park of Henan Agricultural University and the Houshi Country of Zhongmou, Zhengzhou, Henan.There were five or six levels of Pro-Ca. Prohex-Ca was applied through foliage before jointing stage. Then, Investigate the height, internode length, internode stem diameter, internodes fresh weight, 1000-grain weight, grain yield, root vigor, chlorophyll content, the rate of photosynthesis of rice and wheat. The results as follows:(1)Prohex-Ca, 15 g/hm2 can promote the vegetative growth of the plant in general, the internode length, stem length, stem fresh weight, the number of panicles m2, ripened grain ratio, 1000 grain weight and milled rice yield parameters, increased with the application of Pro-Ca, but the effect of reducing the growth is not well.(2)Prohex-Ca, 45 g/hm2 was the best rate to reduce the vegetative growth and increase the quality of rice. Pro-Ca application decreased the height, the fresh weight and dry weight. The content of soluble sugar and protein, the photosynthetic rate and the quality of rice was increased with the application of Pro-Ca.(3)The inhibition is stronger at the rate of Pro-Ca application greater than 60 g/hm2, the root vigor significantly reduce, the normal growth of rice is restrained strictly, the height of rice, ripened grain ratio, 1000 grain weight and yield was decreased strictly. The disease-resistant ability is poor, the yield of rice significantly reduced, it is not conducive to agricultural production. (4)The root vigor of rice was reduced with the different rate of Pro-Ca. Along with the increase of Pro-Ca concentration, Pro-Ca had a tendency to decrease the root vigor of rice and wheat. If Pro-Ca has bigger concentration, then the effect of inhibitting is stronger, however the root vigor is lower.(5)The levels of GA, ABA, IAA, ZR was changed with the application of Pro-Ca compared with the untreated control. Pro-Ca can regulate the growth of rice, delay aging and increase production and quality via change the level of endogenous hormones.