不同形态氮素比例对不同小白菜品种生物量和硝酸盐含量的影响

利用NO-3 N∶NH 4 N为 10 0∶0、5 0∶5 0和 0∶10 0三个硝铵配比的营养液对 12个不结球小白菜品种进行水培试验。结果表明 :不同的硝铵配比对不同品种小白菜的生物量、叶绿素SPAD值、硝酸盐积累量等有着显著的影响 ,同一氮源培养下不同的小白菜品种间也表现出显著的差异 ;12个小白菜品种叶绿素SPAD值随营养液中的NH 4 N比例的增加而升高 ,两者间存在着显著的正相关 ;单株生物量除亮白叶 1号和五月慢在全硝培养中生物量较其他两种配比大外 ,其他 10个品种均在 5 0∶5 0硝铵营养液中表现最好 ;供试的 12个小白菜品种中有 9个品种的硝酸盐积累量随着NH 4 N比例的增加而下降 ,表明适当地配施铵态氮较纯硝营养液能获得更好的产量、更高的叶绿素SPAD值和较低的硝酸盐积累量。

EFFECTS OF DIFFERENT NO3--N/NH4+-N RATIOS ON THE BIOMASS AND NITRATE CONTENT OF DIFFERENT CULTIVARS OF CHINESE CABBAGES

Twelve cultivars of Chinese cabbages were hydroponically grown with three different NO₃^--N/NH₄⁺-N rat ios, i.e., 100:0, 50:50 and 0:100.The result showed that different NO₃^--N/NH₄⁺-N rat ios had a great effect on the fresh matter weight, chlorophyll content (SPAD readings) and nitrate content of the 12 cultivars of Chinese cabbages.In the same nitrogen source the difference was also significant among the different cultivars.The chlorophyll content of the cabbages increased with the increasing NH₄⁺-N/NO₃^--N ratio.Except Liangbaiye 1 and Wuyueman both of which had a higher fresh matter weight in a pure nitrate solution than the other solutions with 0:100 or 50:50 NO₃^--N/NH₄⁺-N ratios, the other 10 cultivars of the cabbages grew best in the solutions with 50:50 NO₃^--N/NH₄⁺-N.In most of the cabbages the nitrate content decreased significantly with the increasing of NH₄⁺-N/NO₃^--N ratio.In conclusion, a proper NO₃^--N/NH₄⁺-N ratio could not only increase the biomass weight and chlorophyll content but decrease the nitrate content of Chinese cabbages as well.