摘要
【目的】研究干旱胁迫下氮沉降对毛竹实生苗生长的影响,揭示不同氮沉降水平下毛竹实生苗对干旱胁迫的生理响应机制,为在大气氮沉降背景下的毛竹经营培育提供理论依据和技术参考。【方法】采用双因素完全随机试验设计,设置2种水分条件(正常供水W、干旱胁迫D)和4个氮沉降水平(无氮CK、低氮LN、中氮MN和高氮HN),分析不同处理条件下毛竹实生苗生物量、叶片相对电导率、丙二醛含量、渗透调节物质含量以及保护酶活性的差异。【结果】干旱胁迫导致毛竹实生苗叶片相对电导率和丙二醛含量比正常水分条件下分别增加16.8%和35.1%,进而抑制苗木生长,显著降低苗木生物量;但同时,苗木脯氨酸含量显著增加49.5%,且保护酶活性显著提高,一定程度上缓解干旱胁迫对苗木的损害。不同氮沉降水平对上述指标的影响规律因水分条件而异。正常水分条件下,随着氮沉降水平的增加,苗木生物量显著增大,叶片脯氨酸含量、相对电导率和丙二醛含量呈先降后增的趋势,且随着时间的延长趋势愈加明显;氮沉降对过氧化氢酶(CAT)活性无显著影响,但提高超氧化物歧化酶(SOD)和过氧化物酶(POD)活性。干旱胁迫条件下,随着氮沉降水平的增加,苗木生物量逐渐增大,但当氮沉降浓度大于60 kg·hm^-2a^-1时,生物量不再增大甚至有减小的趋势;脯氨酸含量、相对电导率和丙二醛含量的变化趋势与正常水分处理相同,而3种保护酶活性呈现先升后降的趋势,其中D-HN处理组最小。【结论】干旱胁迫抑制毛竹实生苗的生长,LN(30 kg·hm^-2a^-2)和MN (60 kg·hm^-2a^-1)氮沉降水平提高了保护酶活性,降低膜脂过氧化程度,减轻了干旱对其生长的抑制,毛竹实生苗抗旱能力提高。而HN(90 kg·hm^-2a^-1)氮沉降水平不能缓解干旱胁迫对毛竹实生苗的膜脂过氧化,反而有加剧干旱胁迫伤害的趋势。
【Objective】In this study, we investigated the effects of nitrogen(N) deposition and drought stress on the growth of Phyllostachys edulis seedlings, and explored physiological response mechanism of the seedlings to drought stress under different N deposition levels, which would be expected to provide a theoretical basis and technical support for the management and cultivation of P. edulis under the background of atmospheric N deposition. 【Method】Two water conditions(normal water supply W, drought stress D) and four nitrogen deposition levels(nitrogen-free CK, low-nitrogen LN, Medium-nitrogen MN and high-nitrogen HN) were set up in a two-factors completely randomized experimental design. The variations of total biomass, leaf electrolyte leakage rate, malondialdehyde content, osmotic regulation substance content, and protective enzyme activity of seedlings of P. edulis under different treatments were analyzed. 【Result】Drought stress resulted in significant increases of relative conductivity(by 16.8%) and malondialdehyde(by 35.1%) content in leaves compared with normal water condition, and hence restrained seedling growth, especially seedling mass. However, at the same time the proline content and protective enzyme activities were significantly increased, which to a certain extent mitigated the damage of drought stress to seedling growth. The effects of different N deposition levels on above parameters varied with water conditions. Under normal water condition, seedling mass increased with N deposition levels, while the proline content, electrolyte leakage rate and malondialdehyde content decreased firstly and then increased. And the tendency became more obvious with the extension of experimental time. Nitrogen deposition significantly increased superoxide dismutase(SOD) and peroxidase(POD) activity, but had no effect on catalase(CAT) activity. Under drought stress, seedlings mass also increased with N deposition levels, but tended to decrease when the N deposition level was higher than 60 Kg ha-1a-1,The effects of N deposition on proline content, the electrolyte leakage rate and malondialdehyde content in leaves were similar to those under normal water condition, whereas the three protective enzymes activities increased firstly and then decreased with N deposition levels, resulting in the enzyme activities in seedlings under the D-HN treatments the lowest. 【Conclusion】Drought stress inhibited the growth of P. edulis seedlings. The N deposition levels of 30 kg·hm-2a-1and/or 60 kg·hm-2a-1increased the activities of protective enzymes, decreased the degree of membrane lipid peroxidation, alleviated the inhibition of drought stress on the growth of P. edulis seedlings, and thus, improved the drought resistance of P. edulis. However, a high rate of N deposition(i.e. 90 kg·hm-2a-1) was not able to alleviate the degree of membrane lipid peroxidation, and even further aggravated the damage of drought stress.
作者
陶晨悦
邵珊璐
史文辉
林琳
汤祎磊
应叶青
Tao Chenyue;Shao Shanlu;Shi Wenhui;Lin Lin;Tang Yilei;Ying Yeqing(State Key Laboratory of Subtropical Silviculture Zhejiang A & F University Lin'an 311300;Shanghai Qingpu Forestry Station Shanghai 201799)
出处
《林业科学》
EI
CAS
CSCD
北大核心
2019年第9期31-40,共10页
Scientia Silvae Sinicae
基金
“十三五”国家重大研发计划课题(2016YFD0600901)
国家自然科学基金项目(31770645)
关键词
毛竹
干旱胁迫
氮沉降
膜脂过氧化
保护酶活性
Phyllostachys edulis
drought stress
nitrogen deposition
lipid peroxidation
protective enzyme activity
作者简介
通讯作者:应叶青.
