| 吴旭红,罗贵强,冯晶旻.外源一氧化氮对Na2CO3胁迫下南瓜幼苗碳氮代谢的影响[J].干旱地区农业研究,2017,35(3):151~158 |
| 外源一氧化氮对Na2CO3胁迫下南瓜幼苗碳氮代谢的影响 |
| Effects of exogenous nitric oxide on the growth and carbon and nitrogen metabolism of pumpkin seedlings under Na2CO3 stress |
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| DOI：10.7606/j.issn.1000-7601.2017.03.24 |
| 中文关键词: 一氧化氮 Na2CO3胁迫 碳氮代谢 南瓜 代谢产物 |
| 英文关键词:nitric oxide Na2CO3 stress carbon and nitrogen metabolism pumpkin metabolic substances |
| 基金项目:黑龙江省教育厅科学技术研究项目(10551332) |
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| 中文摘要: |
| 为探讨外源NO对Na2CO3胁迫下南瓜幼苗碳氮代谢过程的影响，以银辉2号南瓜品种为材料，采用盆栽法研究了80 μmol·L-1 SNP对60 mmol·L-1 Na2CO3胁迫下南瓜幼苗生长、叶绿体色素含量、碳氮代谢相关酶活性及代谢产物量的变化规律。结果表明：Na2CO3胁迫12 d，南瓜幼苗地上和地下部分干重、相对生长量、根冠比、Rubisco羧化活力、光合色素含量和氮代谢相关酶活性均不同程度下降；Rubisco氧化活力、游离氨基酸总量和蛋白水解酶活性显著上升。80 μmol·L-1 SNP外源处理能明显缓解Na2CO3胁迫对南瓜幼苗生长及光合作用的抑制，增加了干物质的积累和光合色素的含量。与Na2CO3胁迫处理相比，干物质积累量、相对生长量、叶绿素和类胡萝卜素（caro）含量、硝酸还原酶（NR）、谷氨酰胺合成酶（GS）、Rubisco羧化酶、淀粉酶（AMY）活性和可溶性蛋白含量分别提高了26.72%、30.45%、17.69%、46.15%、46.43%、30.70%、38.75%、70.0%、65.37%；Rubisco加氧酶、蛋白水解酶活性和游离氨基酸总量分别降低了18.29%、31.76%、28.57%。外源NO通过促进淀粉酶和Rubisco羧化活性的提高和氧化活性的下降，维持了可溶性总糖含量的稳定；通过增强NR、GS和谷氨酸合酶（GOGAT）活性、抑制蛋白水解酶和谷氨酸脱氢酶（GDH）活性，降低叶片中游离氨基酸含量，增加了蛋白质的积累。本研究结论：碱性盐胁迫下，80 μmol·L-1的SNP通过增强南瓜幼苗的光合碳代谢，促进了酮酸转化为氨基酸。通过提高氮代谢相关酶NR、GS、GOGAT活性，促使碳流由光合碳代谢转向氮代谢，维持了盐害下南瓜幼苗碳氮代谢的正常进行，增强了南瓜幼苗抵御Na2CO3胁迫的能力。 |
| 英文摘要: |
| In order to explore the effects of exogenous nitric oxide on metabolism process of carbon and nitrogen of pumpkin seedlings, a pot experiment was conducted to study the effects of 80 μmol·L-1 SNP on the growth of seedlings, the contents of chloroplast pigments, the activities of carbon and nitrogen metabolism related enzymes and the amount of metabolites of pumpkin (cv. Yinhui No.2) seedlings under the stress of 60 mmol·L-1 Na2CO3. The results showed that aboveground and underground dry weight, relative growth rate, root shoot ratio, Rubisco carboxylase activity, light enzyme activity of photosynthetic pigment contents and nitrogen metabolism were decreased in different degrees, while Rubisco oxidation activity, total free amino acids and proteolytic enzyme activity were significantly increased when the seedlings exposed to 60 mmol·L-1 Na2CO3 for 12 d. Application of 80 μmol·L-1 SNP obviously alleviated the inhibition effects of Na2CO3 stress on the seedling growth and photosynthesis, as it increased the plant dry matter and leaf chlorophyll content. Compared with Na2CO3 stress treatment, 80 μmol·L-1 SNP considerably increased dry matter accumulation, relative dry weight, chlorophyll content, carotenoid content, nitrate reductase, glutamine synthetase, carboxylase, amylase activity and soluble protein accumulation by 26.72%, 30.45%, 17.69%, 46.15%, 46.43%, 30.70%, 38.75%, 70.0%, 65.37%, respectively, while decreased protease, oxygenase activity, free amino acid content by 18.29%, 31.76%, 28.57%. Meanwhile, exogenous NO maintained the stability of total soluble sugar content by increasing the activity of amylase and Rubisco carboxylation and decreasing the oxidative activity. Exogenous NO also inhibited the activity of proteolytic enzymes and glutamate dehydrogenase (GDH), decreased the content of free amino acids in leaves, and increased the accumulation of protein by increasing the activity of NR, GS and glutamate synthase (GOGAT). Under alkaline salt stress, 80 μmol·L-1 SNP promoted the keto acid translating into amino acids through the enhancement of pumpkin seedlings photosynthetic carbon metabolism. Meanwhile, by improving the activity of related enzymes NR, GS, GOGAT, 80 μmol·L-1 SNP caused the switch of carbon to nitrogen, maintaining the balance between them under salt stress of Na2CO3. |
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