摘要
植物不但能吸收矿质氮(NH4+-N、NO3--N),而且也能直接吸收有机态氮,如氨基酸、小分子蛋白质等。为探讨有机态氮浓度对番茄幼苗生长和氮代谢的影响,无菌水培条件下采用2个番茄品种(申粉918、沪樱932)设置4种不同浓度(0、1.5、3.0、6.0mmol.L-1)的甘氨酸态氮(Gly-N),研究了番茄幼苗干物质重、吸氮量、氮代谢相关产物和氮代谢关键酶活性。结果表明,无菌水培条件下,随营养液中Gly浓度的增加,番茄植株干物质重、总氮量、地上部和根系游离氨基酸、可溶性蛋白、地上部可溶性糖含量增加。与无氮对照相比,各处理均显著降低了番茄地上部淀粉含量(P<0.05),而Gly浓度对根系淀粉含量无显著影响。随营养液中Gly浓度的增加,番茄地上部和根系的硝酸还原酶(NR)、谷氨酸脱氢酶(NADH-GDH)、丙转氨酶(GPT)和谷草转氨酶(GOT)活性均提高。无氮对照的NR活性与1.5mmol.L-1Gly处理之间差异不显著,而与3.0mmo.lL-1和6.0mmo·lL-1Gly两处理之间差异显著(P<0.05);1.5mmo.lL-1Gly和3.0mmo·lL-1Gly两个处理之间的地上部NADH-GDH、GPT和GOT活性差异不显著。Gly浓度与番茄植株干物质重、总氮量呈显著正相关(R2>0.905**),这表明两个番茄品种均能直接吸收利用甘氨酸。沪樱932吸收Gly的能力显著大于申粉918(P<0.05)。因此,Gly-N可以成为番茄生长的良好氮源,其生理效应受Gly浓度的影响;不同品种番茄对Gly的吸收利用能力不同。
Recent evidence suggests that agricultural and horticultural crops may be able to take up significant quantities of dissolved organic nitrogen（DON）.Our aims were to determine the effects of organic nitrogen concentration on the growth and nitrogen metabolism of tomato seedlings under aseptic hydroponic cultivation.We grew two genotypes of tomato in sterile,hydroponic solution with the addition of organic-N in the form of glycine（Gly-N）at 0,1.5,3.0,and 6.0 mmol·L-1（CK,1.5Gly,3.0Gly,and 6.0Gly treatments）.Both for two cultivars,biomass production,N content,free amino acid and soluble protein content in the shoot and root and soluble sugar content in the shoot were increased significantly with the increment of Gly-N concentration in the nutrient solution.In addition,plant biomass production and N content were positively correlated with the rate of Gly-N supply（R2 〉 0.905＊＊）,although the magnitude of the response was genotype dependent.The addition of Gly-N to the solution unaffected root starch content while it decreased shoot starch content compared to the CK treatment.No significant difference in root soluble sugar content was observed among the CK,1.5Gly and 3.0Gly treatments.The Gly-N supply also significantly affected the activities of N assimilatory enzymes,such as glycine addition increased the activity of nitrate reductase,NADH-glutamate dehydrogenase,glutamate oxaloacetate transaminase and glutamate pyruvate transaminase in the roots and shoots compared with the CK treatment.Our results clearly demonstrated the intrinsic capacity for tomato plants to directly use DON as a sole source of N.Further studies should be carried out to clarify the functional significance of DON in horticultural systems under non-sterile conditions.
出处
《生态学报》
CAS
CSCD
北大核心
2009年第4期1994-2002,共9页
Acta Ecologica Sinica
基金
国家"863"重点资助项目(2006AA10A311)
中国博士后基金资助项目(2005038436)
上海市"蔬菜学"重点学科建设资助项目(B209)
关键词
番茄
甘氨酸浓度
生长
氮代谢
无菌培养
tomato（Solanum lycopersicum）
glycine-N
growth
nitrogen assimilation
aseptic hydroponics
