| The research of plant organic nutrition developed very fast in 1990s. Some strong evidences of the uptake of intact amino acids by plant in the field had been given. Some results had come out of the mechanism study on the uptake and transport of amino acid across the plant cell. Several kinds of amino acid carriers and transfers had been isolated. The study of plant organic nutrition mainly focused on special plant under special conditions (sedge), model plant (Arabidopsis ), important grain crops (rich, barley) and a few vegetables ( cabbage, tomato) . Report on cucumber nutrition was seldom. The cucumber plays an important role in daily life, and the study on cucumber organic nutrition can't be overlooked.Cucumber (Cucumis sativus L. )was used as the plant material in this paper. Nutrition of amino acids on vegetables was studied under sterile culture and in the field.In the amino acid concentration experiment, 5 concentrations of glycine were used to feed cucumber, those were 1,2,3 ,4 and 5 mmol. The treatment without nitrogen was used as CK. Except nitrogen, other essential macroelements and microelements were kept at the same levels in each treatment. Results showed that, the glycine treatments with different concentrations had significantly increased shoot and root fresh weight, plant dry weight and total nitrogen content of cucumber. Increasing the glycine concentration, fresh weight and dry weight of cucumber showed increasing tendency. But if glycine concentration was high than 2 mmol, the increase of fresh and dry weight became slowly, root fresh weight began to decrease. The total nitrogen content of cucumber was positively correlated to glycine concentration (r = 0.9733 ) which indicated that cucumber can absorb intact amino acid and make use of amino acid nitrogen. 3mmol glycine had relatively better effects on cucumber gowth under sterile culture.Five kinds of amino acids were used respectively as the only nitrogen source in another experiment to study the effects of different kinds of amino acids on cucumber growth. One of thoseamino acids (glutamic acid) was anion at the solution pH of 5.8, one was cation (lysine) and three were dipolar neutral ions (glycine, alanine and leucine) . These 5 amino acids highly exist in soil or organic materials. Nitrate treatment was also used in this experiment to find the difference of amino acid nitrogen and inorganic nitrogen. Nitrogen concentration was kept at 42 mg·L-1 i.e.3mmol in each treatment except CK (no nitrogen) . Other essential elements were kept at the same levels. The result showed that, different amino acids had obviously different effects on cucumber growth. Alanine and glycine had better effects on cucumber growth which evidently increased plant height, leaf number, fresh weight and total nitrogen content. The effects of these two amino acids on cucumber grrowth were the same as or close to that of nitrate. The effects of glutamic acid on cucumber were not as good as the above mentioned amino acids, but still increased fresh weight, dry weight and total nitrogen content in certain extend. The worst were lysine and leucine which didn't increase the fresh weight and dry weight. Total nitrogen contents of cucumber fed with lysine and leucine were notably higher than CK which suggested that cucumber absorbed lysine and leucine, but couldn't use it for growth.The effects of different kinds of nitrogen sources on key enzyme NR, transaminase GOT and GPT, GDH, root activities and root cellularity were studied. The effects of different kinds of amino acids on transaminase GOT and GPT were studied too. It was showed that NRA of nitrate nitrogen treatment was the highest of all in roots and leaves. The activities of GOT and GPT varied greatly in roots , shoots, leaves of cucumber, which in roots and leaves was the best of all. This indicated that important assimilation parts of cucumber had no significant relation to amino acid categories. Nitrate nitrogen treatment, prior to glycine treatment, was the best for root activity. Area of taproot transverse section of glycine treatment was obvious bigger than that of CK. This was due to the increase of cell layer and augment of cell volume, which indicated that glycine can qicken cleavage of cambium and growth of parenchyma cell.Besides the study on organic nutrition under sterile culture, the effects of amino acid-N solution on yield and quality of cucumber in the field were also studied. The growing method was substrate culture, in the way of potted planting.In the experiment of amino acid nitrogen solution on cucumber yield and quality, the normal nutrient solution made of chemical fertilizers was used as CK. Contents of N, P, K in the four nutrient solution were kept at the same levels. Four treatments waer set: (1) inorganic nutrient solution. (2)1/3 glycine-N +2/3 nitrate nitrogen nutrient solution. (3 ) 2/3 glycine-N +1/3 nitrate nitrogen nutrient solution. (4) glycine-N nutrient solution. The results were as follows. Under normal conditions, all kinds of nutrient solutions had no significant difference on cucumber yield. Low concentration amino acid nutrient solution increased Vc , soluble sugar and soluble acid...
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