Effect Of Ethylene On Root Morphology&Astomataand Carbohydrate Content In Tr1ticumaestivum L. Under Phosphate Stress

Plant growth and development are widely affected by a large number of environmentalconditions．In order to meet the complex external conditions and ever-changing environment,the plant has evolved a variety of gene types and expression system to regulate and adopt tocope with the challenge from environment in the long-term evolution. Stomata and rootmorphology of Triticum aestivum L.(Xiaoyan22) together with accumulation ofcarbohydrate under low-phosphorus stress were studied to determine the effects of exogenousethylene (ethrel) and ethylene inhibitor (Co2+) on early morphological indicators related tophosphorus efficiency. The results obtained were summarized as follows:(1) Low phosphorus resulted in an increase in endogenous ethylene production, andleaves showed better stability than root.(2)Length of root hair and root hair area increased remarkably while the length of rootdeclined under phosphate deficiency. Ethylene limited the growth of wheat root, such asnumber of root axes and lateral root, root diameter et al. Exogenous ethylene had similareffects on root morphology with low phosphate stress, and Co2+could inhibit the effectsbrought by ethylene. That is to say, changes in root morphology might be caused by ethylene.(3) a. Leaf area declined with lower phosphate concentration and exogenous ethylene,which might lead to an increase in density of stomata in leaf rather than total amount ofstomata of every leaf.b. Stomata tended to close when content of phosphate in the medium was low.However, these kinds of effects could be inhibited by Co2+, which indicated that exogenousethylene might play significant part in early stage of wheat development.c. Number of stomata of every leaf decreased remarkably under phosphate stress,that is to say, content of phosphate in medium increased the number of stomata in wheat.(4) Content of medium phosphate concentration decreased the content of soluble sugarand fructose. Exogenous ethylene declined the content of soluble sugar and fructosesignificantly. Content of shoot reducing sugar climbed continually during the wholecultivation. In conclusion, content of medium phosphate concentration and ethylene regulatedevelopment of wheat in both morphology and physiology ways. It showed that somecharacters were similar in both+P Eth and-P CK, and it implied that low-P stress might affectwheat by changing the amount of ethylene in order to adapt to the environment. Phosphatestarvation led to an increase of endogenous ethylene production, which might be an importantfactor of changes in plants. But the relationship between ethylene and other hormone, whichmodulate wheat growth, was not investigated.