Studies On Mechanism For Effects Of Uniconazole Applied To Seeds On Growth And Development Of Wheat

The studies consisted of'effect of uniconazole(S-3307) applied to seeds on growth and development of different wheat varieties", "effect of uniconazole on transformation of substance after seed germination and its relationship with strong seedlings", "effect of uniconazole applied to seeds on wheat under different densities" and "effect of uniconazole applied to seeds on wheat under different nitrogen level". The effects of uniconazole on morphological and physiological characteristics, yield and grain quality of wheat were studied from 1999 to 2001. The results were as folio ws.1 Effect of uniconazole on morphological characters of wheat1.1 The healthy seedlings established by uniconazole1.1.1 The growth of aerial part retarded by uniconazole S-3307 applied to seeds made the leaves at seedling stage shorter and wider, reduced single leaf area and seedling height, increased dry weight to area ratio of leaf. The higher effect of S-3307 , the higher S-3307 concentration; the lower effect of S-3307, the later growth stage of wheat. S-3307 decreased green leaf area per plant before jointing stage, and increased it after jointing stage. The appearance rate of leaf for S-3307 treatments was quicker than that for the contol, plants of S-3307 treatments at same time had more leaf number than that of the control at the same stage. The date of full length for leaf 3 of S-3307 treatments was l~2days earlier than that of the control.1.1.2 S-3307 promoted tillering of wheat plant Plants of S-3307 treatments tillered one leaf age earlier than that of the control, and their tiller appeared at plumule node.Tillering speed of S-3307 treatments was higher than that of control before 50 days after emergence. The higher S-3307 concentration, the earlier highest tillering speed. Therefore S-3307 increased tiller number per plant and tiller number per unit area, the S-3307 treatment reached the top tiller number per unit area lOdays earlier than the control.1.1.3 S-3307 promoted root growth S-3307 increased root number, fresh root weight, length-basis root-top ratio and weight-basis root-top ratio except root length.1.2 The appearance of plant population after booting stage with large resource and bank established by uniconazole1.2.1 S-3307 promoted leaf growth S-3307 increased the length , area of flag leaf and the second leaf from above, their dry weight :area ratio and total leaf area of both leaves. And S-3307 also made the green leaf area per plant higher than the control after jointing stage. The concentration of S-3307, 20mg/kg, was the best one of all S-3307 treatments.1.2.2 S-3307 promoted root growth S-3307 increased fresh root weight per plant ,kept higher root amount from booting stage to later filling stage than the control. 1.2.3 S-3307 promoted the formation of large resource and bank S-3307 enhanced population of main stem and tiller after booting stage, increased fertile ears per plant and fertile ears per unit area by raising ear-percentage of tiller. S-3307 decreased the possibility of lodging by shortened plant height at maturing stage. The grain capacity per unit area was increased by S-3307 with more grain number per ear.2 Effect of S-3307 on physiological characteristics of wheat2.1 S-3307 changed the endogenous hormone content and their balance2.1.1 S-3307 decreased GA content, decreased ABA content at early time and increased ABA content at late time, and their balance decreased in endosperm after seed germination.S-3307 treatments decreased GA and IAA content, increased ABA and ZT content, therefore GA/ABA,IAA/ABA and GA/ZT decreased in plumule after seed germination. GA,IAA and ZT content of S-3307 treatments was reduced, ABA content of S-3307 was lower at early time and was higher at later time than that of the control, so GA/ABA, IAA/ABA, ZT/ABA and GA/ZT decreased in radicle after seed germination.2.1.2 IAA content in tillering node of S-3307 treatments was lower at tillering stage, and higher af...