Study On Effects Of Potassium Fertilizer On Quality And Main Relative Mechanism Of Tomato In Greenhouse

Efeects of potassium fertilizer on primary nutrition quality,locopene,hardness of fruit,nitriate content,flavor quality and their main relative mechanism of Autumn tomato in greenhouse were studied with JINGUAN NO.1.Also,the relativity of contents of locopene and nitrate,primary nutrition components,and the flavor compounds were compared and analysed.Five K₂O amount levels were designed in the experiment under the condition of middle amount of N and P fertilizer,which were 0,75,150,225,300 kg/hm² applied.The results were as follows:1.The content of Dry Matter of each treatment was about 6%-8%,and it increased as the potassium fertilizer increased.The contents of Vitamine C,soluble sugar,soluble protein of tomato fruits were increased obviously when proper amount of potassium fertilizer was applied.However,when the amount of potassium was more than 225 kg/hm²,the targets above had the tendency of degression.In the range of 0-300kg/hm²,the content of Organic acid increased as the potassium fertilizer increased.2.The hardness of tomato fruits increased gradually as the amount of K₂O increased.It was significant to improve the taste and capabilities of endurance of storing and transportation.3.The content of locopene of tomato increased when the amount K₂O applied increased within the range of 0-150kg/hm².When the amount of K₂O was more than 150kg/hm²,it began to decrease.4.The content of nitrate of tomato fruit decreased as the amount of K₂O applied increased within the range of 0-225kg/hm².When the amount of K₂O was out of the range,it had the tendency of increase.5.Elevene characteristic flavor compounds were separated from JINGUAN NO.1,among of which,Aldehyde(six kinds)hold the most.The contents of characteristic flavor compounds of tomato,such as trans-2-hexenal,cis-3-hexenal, Ethanal,increased remarkably.The opposite content of trans-2-hexenal was T2＞T4＞T1＞T0＞T3;The opposite content of cis-3-hexenal,was T2＞T1＞T3＞T0＞T4; The opposite content of Ethanal was T2＞T3＞T1＞T4＞T0.6.The APX activities of tomato fruit increased while the APX activities of the leaf decreased as the amount of K₂O increased.The APX activities of the leaf played the main role in the accumulation of Vitamine C.The AI and NI activities increased in the fruit and decreased in the leaf as the amount of K₂O increased within the range of 0-150kg/hm².The content of soluble sugar was positively relative to the AI activities of the fruit,while negatively relative to he AI and NI activities of the leaf.The NR activities increased as the amount of K₂O applied increased within the range of 0-225kg/hm².When the amount of K₂O applied reached 300kg/hm²,it decreased obviously.The NR activities in the laef played the main role in the accumulation of nitrate.The LOX activities increased greately as potassium fertilizer applied increased, the LOX activities was positively relative tothe content of volatitle compounds. 7.The characteristic flavor compounds of tomato were positively relative to the contents of Vitamine C,soluble sugar,soluble protein,locopene,Organic acid,while negatively relative to the content of nitrate.