钾对日光温室黄瓜糖、维生素C、硝酸盐及其相关酶活性的影响

以津优1号为试材,设K2O施用量分别为0、300、6009、00、1200.kg/hm2.5个处理,研究了不同施钾水平对黄瓜主要品质和有关酶活性的影响。结果表明,在施K2O.300～900.kg/hm2范围内,随着用量的增加,黄瓜叶片和果实中可溶性糖含量与SPS活性均逐渐升高,而K2O用量达1200.kg/hm2时,二者趋于下降。果实中的可溶性糖含量与叶片和果实SPS活性呈显著正相关;而叶片中糖含量与其SPS活性没有明显的相关性。在K2O用量为300～900kg/hm2时,黄瓜果实的Vc含量高于对照,叶片APX活性降低,而果实中的APX活性提高。黄瓜叶片与果实的硝酸盐含量均随施钾量的增加而逐渐降低,K2O用量在0～900.kg/hm2范围内,黄瓜叶片的NR活性较高,且随着钾肥用量的增加而升高;当K2O用量达到1200.kg/hm2时,NR活性明显下降,果实中的NR活性很低,处理间差异不显著。

Effects of potassium on sugar, vitamin C, nitrate contents and their relevant enzymes of cucumber in solar-greenhouse

In order to explore the affecting mechanism of potassium on cucumber quality and provide a scientific and (rational) fertilizer practice for cucumber planting, the effect of potassium fertilization on main quality and their correlative enzymes of cucumber in solar-greenhouse were studied. The test crop was Jinyou No.1 and 5 application rates of K (K₂O 0, 300, 600, 900, and 1200 kg/ha) were set up in this experiment. The result indicated that both the soluble sugar content and SPS activity of fruit and leaves of cucumber increased when application rate of K₂O was in 300—900 kg/ha scope. However, when 1200 kg/ha K₂O was applied,both of them showed a drop tendency. There was a positive correlation between the soluble sugar content of fruits and SPS activity of leaves and fruits, but no obvious correlation between sugar content and SPS activity of leaves was found. When 300—900 kg/ha K₂O were applied, Vc content of fruits were higher than that of CK. The APX activity decreased in leaves while increased in fruits. Both in leaves and fruits, the (nitrate) content decreased with the increase of K₂O. The NR activity of leaves were relatively higher, and increased with the increase of K₂O application when the application rate of K₂O was in the scope of 0—900 kg/ha, however, it (decreased) markedly when 1200 kg/ha K₂O was applied. The NR activity of fruits was quite low, and there were not obvious differentia among different treatments.