Effects Of The Supply Of Nitrogen?Phosphate And Potassium On The Growth And Total Phenolic Contents Of Leaf Mustard And Lettuce

In this study, leaf mustard and lettuce were used as testingmaterials to study the effects of nutrient supply of nitrogen?phosphorus and potassium on the growth and total phenolic contents inthis two vegetables. Firstly, there were three cultivation methods includingdeep flow technique(DFT), nutrient film technique(NFT) and soil culturewhich were used for finding out the effects of different cultivation methods on the growth and total phenolic contents of lettuce and mustard. Meanwhile, there was another experiment under different nutrient solutions suppling conditions-different nitrogenphosphate or potassium levels, andused two different cultivations—still hydroponics and soil cultivationstudiedthe effects of different nutrient supply conditionson the growth quality and total phenolic contents of lettuce and leaf mustard. The main results were as follows:1. In the sameconditions of nutrients supply, hydroponic leaf mustard and lettuce had higher yields than those grown in soil culture. Leaf mustard and lettuce grown in deep flow technique received the highest yields. Different cultivation methods of leaf mustard and lettuce have greatly influences on secondary metabolism within these two vegetables. Vitamin C contents of mustard and lettuce in the hydroponic culture was significantly higher than those grown in soil culture.Leafmustard and lettuce under 0.5 times nitrogen, phosphate and potassium levels were significantly higher than those in the two other nutrient levels.2.For these two kinds of vegetables, the root activitiesin soilculture conditionwere far less than those vegetables in hydroponic culture. There was obvious effectsbetween these two culture methods on the absorption and utilization of mineral nutrients.3.Total phenolic contents and polyphenol oxidase activities were affected by different cultivation methods. Under the same environmental and nutritional level of theatment, the vegetablesin soil culture contained higher total phenolic contents and higher polyphenol oxidase activities than those in hydroponic condition. And with the change of nutrient supply, soil culture vegetables could be more easily affected than those of still hydroponic vegetables. But toomore contents of total phenolicmaterials andpolyphenol oxidase activitiesin these two vegetables would decrease the quality of vegetables.