低氮胁迫对不同光皮桦基因型苗期生长及生理生化特征的影响  

Effect of Low Nitrogen Stress on the Growth, Physiological, and Biochemical Characteristics of Different Betula luminifera Genotypes

作　　者：程丽丽 潘樱 林艳 林仕雄 童再康[1] 张俊红[1] CHENG Lili;PAN Ying;LIN Yan;LIN Shixiong;TONG Zaikang;ZHANG Junhong(The State Key Laboratory of Subtropical Silviculture,Zhejiang A&F University,Hangzhou,Zhejiang 311300)

机构地区：[1]浙江农林大学亚热带森林培育国家重点实验室,浙江杭州311300

出　　处：《核农学报》2020年第11期2435-2443,共9页Journal of Nuclear Agricultural Sciences

基　　金：浙江省农业(林木)新品种选育重大科技专项(2016C02056-2)。

摘　　要：为探讨低氮胁迫对不同基因型光皮桦(Betula luminifera)生长及生理生化响应特性,本研究采用裂区设计,以光皮桦G49-3、G50-1和优3组培苗为材料,通过水培培养研究其在正常供氮(CK,15 mmol·L^-1 NO3-)和低氮胁迫(LN,0.03 mmol·L^-1 NO3-)条件下的苗期生长及生理生化响应。结果表明,低氮胁迫处理21 d后,3个光皮桦基因型的叶绿素含量、株高、地上部干重、地上氮含量和氮积累量均显著降低,其中G49-3降幅最大,G50^-1降幅最小;3个光皮桦基因型根冠比、根系总根长、总表面积和平均直径均增加;叶片过氧化物酶(POD)、超氧化物岐化酶(SOD)和硝酸还原酶(NR)活性降低,G50^-1降幅最低。实时荧光定量PCR(RT-qPCR)分析表明,相较于CK,低氮胁迫处理下3个光皮桦基因型叶和根中NRT1.1和NRT1.2均下调表达,而NRT2.1在根中上调表达,说明根中NRT2.1在低氮胁迫下的硝酸盐转运过程中发挥主要作用。综合隶属函数分析显示,G50^-1平均隶属函数值(0.73)高于优3(0.44)和G49-3(0.34),表明G50^-1耐低氮能力最强,而G49-3对低氮胁迫最敏感。本研究结果揭示了光皮桦响应低氮环境的生理机制,同时表明运用常规遗传改良手段筛选和培育耐低氮、氮高效利用的光皮桦良种是可行的。To investigate the growth, physiological and biochemical responses of different genotypes of Betula luminifera under low nitrogen stress, we conducted a split-plot experiment using seedlings of three genotypes: G49-3, G50-1, and U3. There B. luminifera plants were grown in Hoagland nutrient solution under control(CK, 15 mmol·L^-1 NO3-) and low nitrogen(LN, 0.03 mmol·L^-1 NO3-) treatments. After 21 days of LN treatment, the chlorophyll content, plant height, shoot dry weight, shoot N content, and N content were significantly reduced in all three B. luminifera genotypes, with the greatest decrease in G49-3 and the lowest decrease in G50^-1. Root-shoot ratio, total root length, total root surface area, and root average diameter were higher under LN treatment. Peroxidase(POD), superoxide(SOD), and nitrate reductase(NR) levels were lower in leaves with LN treatment;G50^-1 was the genotype with the least influences. Quantitative reverse-transcription polymerase chain reaction(RT-qPCR), revealed that NRT1.1 and NRT1.2 were down-regulated in both leaves and roots of all three genotypes under LN. In contrast, NRT2.1 was up-regulated in roots, suggesting that NRT2.1 plays a major role in nitrate transfer in B. luminifera roots under LN stress. Comprehensive membership function analysis showed that the average value of G50^-1(0.73) was higher than those of U3(0.44) and G49-3(0.34), indicating that among these genotypes, G50^-1 is the most tolerant to LN stress and G49-3 the most sensitive. These results reveal the physiological mechanism of B. luminifera adapting to low nitrogen environment. It also suggest that it is feasible to select and breed improved varieties of B. luminifera with high LN tolerance and N efficiency using traditional genetic improvement strategies.

关 键 词：光皮桦 基因型 低氮胁迫 生物学响应 

分 类 号：S792.15[农业科学—林木遗传育种]