Research On Plant Growth Regulator Using Bioactive Peptides

Because the vast majority of plant growth substances currently approved have certain toxicity and the food safety incidents involved the toxicity offen occur.Therefore,it is urgent need new plant growth substances which are non-toxic,harmless and could promote plant growth.In this study,the effects on promoting different kinds of plants growth and preservation were determined using bioactive peptides IK-7 and YR-7,which were discovered early,Furthermore,the mechanism for promoting plant growth were expored preliminarily.Firstly,filter paper method was used to test the effect of IK-7 and YR-7 about the plant growth.IK-7 and YR-7 played a significant role in promoting seed germination of plants.IK-7 and YR-7 could effectively improve seed vigor,sprouting uniformity and so on.The effects were much stronger than the other plant growth substances.By testing fruit seeds,for examples watermelon and melon seeds,IK-7 and YR-7 with concentration of 0.01 mg/L respectively promoted watermelon seeds growth and the increase rate were up to 82.40%and 85.79%.So did melon seeds and increase rate were up to 49.00%and 46.23%.By testing crops,for examples rice and waxy corn,IK-7 with concentration of 0.001 mg/L promoted rice seeds growth and the increase rate was only 16.04%and YR-7 with concentration of 0.01 mg/L promoted rice seeds growth and the increase rate was only 34.12%.It was different for waxy corn,IK-7 with concentration of 0.01 mg/L promoted rice seeds growth and the increase rate was 52.03%and YR-7 with concentration of 0.1 mg/L promoted rice seeds growth and the increase rate was only 61.50%.By testing flowers,for instance carnations,IK-7 with concentration of 0.0001?0.01 mg/L promoted carnations seeds growth and the increase rate was 57.92%and YR-7 with concentration of 0.0001 mg/L promoted carnations seeds growth and the increase rate was 59.10%.By testing vegetables,for instance water spinach,IK-7 with concentration of 0.1 mg/L promoted water spinach seeds growth and the increase rate was only 30.61%and YR-7 with concentration of 0.01 mg/L promoted water spinach seeds growth and the increase rate was only 25.90%.By testing different kinds of plant growth substances,for instance NAA,GGR-6,GA3 and so on,IK-7 and YR-7 had obvious advantages in the matter of promoting seed germination of watermelon,melon,rice,waxy maize,carnations and water spinach.Secondly,the effects on preservation were determined to the change of brassica chinensis's fresh weight loss rate and content of protein.The results showed that IK-7 remained brassica chinensis's fresh weight loss rate at a low level,the content of protein and sensory indicators kept at high levels,which were stronger than those of 6-BA.So IK-7 could preserve fresh of vegetable.Thirdly,the mechanism of promoting plant growth were explored.The ultrastructure of seeds treated by active peptide was investigated by transmission electron microscopy methode.It showed that radicle cell contents and various organelles of watermelon seed treated by the two peptides separately were clearly visible to have many rough endoplasmic reticulums associated with protein synthesis,Golgi apparatus raleted to protein's processing and packaging and polysaccharide synthesis,and mitochondrions involved in providing energy for the organism in radicle cells.For the further exploration of the mechanism,the change of protein content,SOD,POD,CAT activity and endogenous hormone IAA,GA3 and ABA content of watermelon seeds treated by IK-7 and YR-7 during germination were tested,respectively.It showed that the highest protein content was up to 0.587 gprot/L.The highest SOD activity was 228.92 U/mgprot.The highest POD activity was 27.04 U/mL.The highest CAT activity were 21.01 U/mgprot.The trends of protein content,SOD,POD and CAT activity is basically the same,and CAT activity showed little change.Changes of endogenous hormone IAA,GA3 and ABA of watermelon seeds treated by IK-7 and YR-7 basically decreased firstly and increased subsequently with incubation time,and endogenous hormones's content in revealed seeds was significantly lower than unrevealed seeds.Furthermore,average of treatment group were less than CK,which may be the reason that untreated seeds had low vigor and germinated slowly.