原卟啉化合物JE02对水稻生长的作用及生理机制OA

[Objectives]The paper aimed to clarify the impact of the protoporphyrin-structured compound JE02 on rice growth and explore its growth-promoting mechanism,so as to provide a theoretical basis for the rational use of protoporphyrin-structured plant growth regulators.[Methods]The whole-plant bioassay method was adopted to investigate the impact of the foliar and stem treatment of JE02 on rice growth.Meanwhile,relevant physiological mechanisms were studied from aspects such as photosynthetic parameters,root vitality and antioxidant capacity.[Results]When the 3-leaf stage rice variety'Nanjing 46'was sprayed with JE02 within the dose range of 3.75-30.00 mg·hm-2,there was a significant difference in fresh weight compared with the blank control,with an increase of 4.28%-12.46%compared with the blank control,and the optimal promoting dose was 15 mg·hm-2.When 15 mg·hm-2 of JE02 was sprayed continuously for three times during the tillering stage,jointing stage and booting stage,the promoting effect on rice was the most obvious,with the fresh weight,stem diameter,root weight and root number increasing by 9.32%,12.92%,16.50%and 8.95%,respectively.When JE02 was sprayed at the seedling stage,the root vitality of rice showed a significant difference compared with the control,reaching the maximum value of 498.93 mg·g-1·h-1 five days after application,which was 30.77%higher than that of the control group.JE02 could enhance the activities of antioxidant enzymes(SOD,POD,CAT)and the content of non-enzymatic antioxidants(AsA)in rice during the grain-filling stage.When the difference was the largest,they could be increased by 11.98%,41.90%,16.92%and 73.70%compared with the control,respectively.It could reduce the content of malondialdehyde(MDA)by 33.11%compared with the control,while having no significant impact on the production rate of superoxide anions(O·-2)and the content of hydrogen peroxide(H2O2).It could also improve photosynthesis by increasing the chlorophyll content,net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr)and the actual photochemical efficiency of photosystem Ⅱ(ϕPSⅡ)of the flag leaf of rice,but had no significant impact on the intercellular CO2 concentration(Ci)and the maximum photochemical efficiency of photosystem Ⅱ(Fv/Fm).[Conclusions]JE02 has a promoting effect on rice growth.It is speculated that it promotes rice growth by improving rice root vitality,enhancing photosynthesis and increasing the activities of antioxidant enzymes.