养分和水分状况对刺梨树体硝酸还原酶活性与氮素营养的影响

以贵农5号刺梨品种为材料,研究了不同氮素形态供氮条件、营养元素缺素胁迫和不同土壤水分状况下刺梨植株根、茎、叶的硝酸还原酶活性(NRA)及其与总氮及硝态氮含量的关系。结果表明,供应的氮源为30%NO3--NH4+70%NH4+-N时,能够促进刺梨对氮素的吸收,根和叶中总氮含量最高,而NRA并不最强。单纯供应NO3--N时,根和叶中的NRA最强,但总氮含量显著低于同时供应NO3--N和NH4+-N的处理。单纯供应NO3--N和同时供应NO3--N和NH4+-N时,刺梨根和叶中NRA与总氮含量、硝态氮含量呈显著的负相关;同时供应NO3--N和NH4+-N时,刺梨对氮素的吸收并不完全受NR的支配。在缺氮、缺钼条件下,根和叶中都没有检测出NRA;在缺铁、缺硼条件下,根中的NRA很低,叶中没有检测出NRA;其他营养元素缺素胁迫对根和叶中NRA抑制程度的强弱顺序为缺Zn>缺P>缺Mg>缺Ca。根、叶、茎中的NRA与土壤含水量呈极显著正相关,而NO3--N含量则与土壤含水量呈极显著负相关。

Effects of nutrition condition and drought stress on NR activity and Nitrogen nutrition in organs of Rosa roxburghii

Rosa roxburghii Tratt. cv. Guinong 5 was used to investigate the changes of NR activity under the conditions of supplying different nitrogen form, nutrient deficiency and soil drought stress respectively. The result showed that NR activity in root and leaf increased with the increase of NO3--N proportion, but it was not expected that N content in the organs lower than that treatment of supplying NO3--N and NH4 -N. When the N and Mo were deficient in the medium, there no NR activity was detected. In the Fe- and B-deficient culture medium, NR activity in root was low and that in leaf was not inspected. The inhibition of other nutrient elements deficiency to NR activity was Zn>P>Mg>Ca. NR activity in root, stem and leaf presented significant positive correlation with soil water content. By contraries, in the root and leaf, there was a significant negative correlation between NO3--N content and soil water content.