论文标题:氮素营养对网纹甜瓜生长和品质的影响
Effects of Nitrogen Supply on the Growth and Quality of Muskmelon
论文作者
论文导师 别之龙,论文学位 硕士,论文专业 蔬菜学
论文单位 华中农业大学,点击次数 129,论文页数 83页File Size3804K
2006-05-01论文网 http://www.lw23.com/lunwen_31223982/
muskmelon;nitrogen concentration;nitrogen forms; quality
随着设施栽培技术推广应用，厚皮甜瓜生产打破了南北方种植界限，南方在多雨湿润气候条件下也能生产出优质高档的厚皮甜瓜，实现了厚皮甜瓜周年供应，但由于肥水管理不当等原因，厚皮甜瓜品质低劣问题一直困扰着生产。如何科学合理施肥来提高厚皮甜瓜的产量与品质已成为甜瓜栽培中亟待解决的问题。本试验以两个网纹甜瓜(Cucumis melo var．reticulatus Naud．)品种(春丽和蜜玲珑)为材料，通过基质栽培方式，研究了氮素营养供应对网纹甜瓜生长和品质的影响。试验由不同氮素浓度、不同氮素形态配比、营养液分段管理三部分组成。 1．研究了4种氮素浓度(4mmol·L~(-1)、8mmol·L~(-1)、12mmol·L~(-1)、16mmol·L~(-1))对网纹甜瓜(品种为“春丽”)生长和品质影响。结果表明，不同氮素浓度显著影响了甜瓜各部位的干物质分配，果实成熟期，8mmol·L~(-1)氮处理下甜瓜果实干重占全株的百分比最大。叶片叶绿素含量和硝酸还原酶活性在氮素浓度为12mmo·L~(-1)时最大。不同氮素处理下叶片净光合速率，气孔导度和蒸腾速率的日变化均为单峰曲线，细胞间CO_2浓度的日变化呈“V”字型变化。8mmol·L~(-1)氮处理下平均单果重最重，果实的Vc、可溶性糖含量和糖酸比均是8mmol·L~(-1)氮处理下最高，可溶性固形物随氮素浓度的增加而增加，硝酸盐含量在12mmol·L~(-1)氮处理下最高。不同氮素浓度处理显著影响了网纹甜瓜各部位中的矿质元素含量，随着氮处理浓度的增加，植株各器官中的氮含量逐渐增加，而果实和叶片中的磷和钾含量逐渐降低，叶片中的钙和镁含量显著高于植株其他部位，果实中的钙含量随氮处理浓度的增加逐渐上升，而果实中的镁含量则逐渐降低。8mmol·L~(-1)氮处理是比较适合网纹甜瓜生长和品质形成的氮浓度。 2．研究了4种氮素形态配比(NO_3~-—N／NH_4~+—N分别为100∶0、75∶25、50∶50和25∶75)对网纹甜瓜生长和品质的影响。结果表明，不同氮素形态配比影响了植株各部位的干物质分配。随氮素形态中铵态氮比例的增加，叶片中硝酸还原酶活性、硝酸盐含量和可溶性蛋白质含量逐渐降低。游离氨基酸含量在NO_3~-—N：NH_4~+—N为50：50的处理中最高。两个甜瓜品种在各生育期的叶绿素、净光合速率(Pn)、气孔导度(Gs)在NO_3~-—N／NH_4~+—N为75：25时最高。两个甜瓜品种的最大光化学效率(Fv／Fm)在NO_3~-—N／NH_4~+—N为75：25时最高；光反应猝灭系数(qP)和PSⅡ的实际光化学效率(ΦPSⅡ)在NO_3~-—N／NH_4~+—N为100：0时最高，PSⅡ的天线转换效率(Fv’／Fm’)和非光反应猝灭系数(NPQ)在NO_3~-—N／NH_4~+—N为25：75时最高。品种“春丽”和“蜜玲珑”平均单果重分别在NO_3~-—N／NH_4~+—N为75：25和50：50时最重。果实中的Vc含量在NO_3~-—N／NH_4~+—N为50：50时
With the rapid development and demonstration of protected cultivation, the production of muskmelon broke through the limit of cultivation area between the south and north China. Muskmelon now can be cultivated in south China, but the low quality of muskmelon is the biggest problem in the production owing to the irrational application of chemical fertilizers. The effects of nitrogen supply on the growth and quality of muskmelon (Cucumis.melo. var.reticulatus Naud. cv. Chunli and Milinglong) were investigated in this paper by using substrate culture. The research consisted of three experiments: different nitrogen concentration experiment; different nitrogen forms experiment and different nitrogen concentration irrigation according to the different plant growth stage. The main results were as follows:1. Effects of four nitrogen concentrations (4mmmol·L~(-1), 8mmmol·L~(-1), 12mmmol·L~(-1), 16mmmol-L~(-1)) on the growth and quality of muskmelon (cv. Chunli) were investigated. The results showed that the highest dry matter percentage of muskmelon fruit was obtained by 8mmmol·L~(-1) nitrogen treatment. The highest chlorophyll content and NR activity were obtained by 12mmmol·L~(-1) nitrogen treatment. Diurnal changes of net photosynthetic rate (Pn), stomatal conductance(Gs) and transpiration rate (E) of muskmelon leaves were a single-apex curve, whereas diurnal change of intercellular CO_2 concentration(Ci) was a "V" style in all treatments. The heaviest single fruit was obtained by 8 mmmol·L~(-1) nitrogen treatment. Fruit nitrate content and TSS content increased significantly with increasing concentration of N in the nutrient solution. The highest vitamin C concentration, soluble sugar and sugar/acid ratio were obtained by Smmol·L~(-1) nitrogen treatment. N concentration in all parts of muskmelon plant increased with increasing concentration of N in the nutrient solution. The P and Kconcentration in Fruit and leaf decreased as nitrogen concentration increased. Leaf Ca was significantly higher than other organs. Fruit Ca concentration increased whereas fruit Mg concentration decreased as nitrogen concentration increased. Smmmol·L~(-1) nitrogen treatment was the best nitrogen concentration for the growth and quality of muskmelon.2. Effects of four nitrogen forms (NO_3~--N/NH_4~+-N were 100:0, 75:25, 50:50 and 25:75, respectively) on the muskmelon growth and quality were investigated in this experiment. The results showed that different nitrogen forms significantly affected the dry matter accumulation percentage in different plant organs. Leaf nitrate reductase activity,
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