低温对结球甘蓝幼叶氮代谢活性及光合色素的影响

Effects of low temperature on nitrogen metabolism activities and photosynthetic pigments in different cabbage seedlings

【目的】探讨不同耐寒性甘蓝品系在低温胁迫下氮代谢相关指标及色素含量间的差异,为甘蓝品系筛选和耐寒性栽培提供理论依据。【方法】以2个耐寒(231、235)和2个不耐寒(161、163)甘蓝品系为材料,测定分析低温胁迫下其硝态氮(NO3--N)、铵态氮(NH4^+-N)、硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合酶(GOGAT)、谷氨酸脱氢酶(GDH)活性和光合色素的变化情况。【结果】随着低温胁迫时间的延长,耐寒甘蓝品系中可溶性蛋白呈增加趋势,低温胁迫3 d时,耐寒甘蓝品系中可溶性蛋白含量显著增加(P<0.05,下同),品系231和235分别增加15.79%和12.70%,不耐寒甘蓝品系中蛋白含量趋于平稳,在常温恢复2 d后(处理5 d),各处理的可溶性蛋白含量略有降低;NO3--N含量、氮代谢相关酶活性和光合色素含量在低温胁迫期间均呈降低趋势,胁迫5 d时变化不显著(P>0.05,下同);NH4^+-N含量则呈增加趋势,胁迫5 d时,品系231和235幼叶的NH4^+-N含量不再显著增加,而品系161和163幼叶的NH4^+-N含量依然呈显著增加趋势,分别增加27.05%和20.85%。【结论】在低温胁迫下,耐寒甘蓝品系能在一定程度上维持氮代谢关键酶的活性和光合色素含量,以促进氮代谢和光合作用,从而增加其对低温的适应性。

【Objective】The differences of nitrogen metabolism related indexes and photosynthetic pigments among cabbage lines with different chilling tolerance under low temperature stress were studied in order to provide theoretical basis for selection and chilling tolerance cultivation of cabbage varieties.【Method】Changes of nitrate nitrogen(NO3--N),ammonium nitrogen(NH4^+-N)and nitrate reductase(NR),glutamine synthetase(GS),glutamic acid synthase(GOGAT)and glutamate dehydrogenase(GDH)activities and photosynthetic pigments were measured and analyzed in two chilling-tolerant(231,235)and two chilling-sensitive(161,163)cabbage strains under chilling stress. 【Result】With the extension of low-temperature stress time,the soluble protein in chilling-tolerant cabbages increased,and it reached significant level on day 3 of low temperature stress(P<0.05,the same below),with increase of 15.79% and 12.70% in 231 and 235,respectively. The protein content of chilling-sensitive cabbages stabilized on day 3 of low-temperature stress,and after 2 d of normal temperature recovery(5 d after treatment),the protein content of the treatment was slightly reduced. NO3--N content,nitrogen metabolism-related enzyme activities and photosynthetic pigment content all showed a decreasing trend during low-temperature stress,and did not change significantly after 5 d of treatment(P>0.05,the same below). The NH4^+-N content showed an increasing trend,on day 5,NH4^+-N in cabbages 161 and 163 still showed a significant increase,with an increase of 27.05% and 20.85% in 161 and 163,respectively,while those in 231 and 235 were no longer significantly increased.【Conclusion】Under low-temperature treatment,the chilling-tolerant cabbage lines can maintain the activities of key enzymes of nitrogen metabolism and photosynthetic pigments to promote nitrogen metabolism andphotosynthesis,thereby increasing their adaptability to chilling stress.