生态环境学报 ›› 2022, Vol. 31 ›› Issue (12): 2292-2301.DOI: 10.16258/j.cnki.1674-5906.2022.12.003

• 研究论文 • 上一篇    下一篇

施氮和干旱对杉木和青冈幼苗生物量及根系形态的影响

高歌1,2,3(), 葛晓改1,3, 周君刚4, 周本智1,3, 李正才1,3,*(), 杨南5   

  1. 1.中国林业科学研究院亚热带林业研究所,浙江 杭州 311400
    2.南京林业大学,江苏 南京 210037
    3.国家林业和草原局钱江源森林生态系统定位观测研究站,浙江 杭州 311400
    4.杭州市富阳区农业农村局,浙江 杭州 311400
    5.云南西双版纳国家级自然保护区管护局,云南 景洪 666100
  • 收稿日期:2022-08-19 出版日期:2022-12-18 发布日期:2023-02-15
  • 通讯作者: *李正才,E-mail: lizccaf@126.com
  • 作者简介:高歌(1999年生),女,硕士研究生,研究方向为森林生态系统结构与功能。E-mail: Gaogewy@163.com
  • 基金资助:
    国家自然科学基金项目(32071756);中央级公益性科研院所基本科研业务费专项(CAFYBB2020ZE001);浙江省基础公益研究计划(LGF20C160001)

Effect of Drought Stress and Nitrogen Addition on the Biomass and Root Morphology of Cunninghamia lanceolata and Cyclobalanopsis glauca Seedlings

GAO Ge1,2,3(), GE Xiaogai1,3, ZHOU Jungang4, ZHOU Benzhi1,3, LI Zhengcai1,3,*(), YANG Nan5   

  1. 1. Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, P. R. China
    2. Nanjing Forestry University, Nanjing 210037, P. R. China
    3. Qianjiangyuan Forest Ecosystem Research Station, State Forestry Administration of China, Hangzhou 311400, P. R. China
    4. Hangzhou Fuyang District Bureau of Agriculture and Rural Development, Hangzhou 311400, P. R. China
    5. Yunnan Xishuangbanna National Nature Reserve Management and Protection Bureau, Jinghong 201210 P. R. China
  • Received:2022-08-19 Online:2022-12-18 Published:2023-02-15

摘要:

探究氮素添加后不同亚热带树种生物量和根系形态对干旱的响应特征,为干旱下植物幼苗的水肥管理和抗旱能力的提升提供理论依据。试验选取杉木(Cunninghamia lanceolata)和青冈(Cyclobalanopsis glauca)为研究对象,设置未施氮(N0,0 mg?kg?1,以N计,下同)和施氮(N1,100 mg?kg?1)2个氮处理及正常水分(CK,80%—85% FC)、中度干旱(MD,50%—55% FC)和重度干旱(SD,30%—35% FC)3个土壤水分梯度,氮处理结束后于8月中旬展开水分控制试验,干旱60 d后进行破坏性采样,测定和分析两树种生物量及根系形态特征。结果显示,施氮促进了相同干旱水平下杉木和青冈地上部生物量的积累,并促使重度干旱下(N1SD)青冈的根干质量(31.7%)和总生物量(17.5%)显著增加(P<0.05),但对干旱下(N1MD和N1SD)杉木根干质量和总生物量表现为抑制作用;施氮改变了干旱下青冈和杉木的生物量分配格局,不同水分条件下青冈生物量分配对氮素的响应有所不同,且中度干旱下氮肥作用效果更强,氮添加促使相同干旱组杉木的茎生物量比、叶生物量比及茎叶比增加,而根生物量比(19.4%和30.0%)、比根长(39.8%和28.5%)和根冠比(28.3%和38.1%)均显著降低(P<0.05);施氮显著抑制了干旱组(N1MD和N1SD)杉木各径级根长、根表面积和根体积(P<0.05),这种抑制作用在中度干旱时更为强烈,而氮素对重度干旱下青冈根系生长及形态的影响较大且表现为正效应。研究表明,干旱下杉木和青冈在生物量积累与分配和根系形态方面对氮素添加表现出不同的利用策略,适量的氮素在一定程度上能够促使青冈幼苗抵御重度干旱的威胁,尽管施氮对干旱胁迫下杉木幼苗的生长无促进效果,但幼苗期的杉木亦能通过权衡地上及地下的生物量分配以缓解干旱胁迫对自身的伤害。

关键词: 杉木, 青冈, 氮肥, 干旱, 生物量, 根系形态

Abstract:

Exploring the response characteristics of biomass and root morphology of different subtropical tree species to drought after nitrogen addition can provide a theoretical basis for water and fertilizer management of plant seedlings under drought and improvement of drought resistance. Cunninghamia lanceolata and Cyclobalanopsis glauca under two nitrogen addition treatments (N0, N 0 mg?kg?1; N1, N 100 mg?kg?1) were subjected to three treatments of soil water including normal water (CK, 80%-85% FC), moderate drought (MD, 50%-55% FC) and severe drought (SD, 30%-35% FC). After nitrogen treatment, the water control test was carried out in the middle of August, and destructive sampling was carried out after 60 days of drought to measure and analyze the biomass and root morphology of the two species. The results showed that nitrogen addition increased the aboveground biomass in C. lanceolata and C. glauca seedlings under the same water treatment, and significantly increased the root biomass (31.7%) and total biomass (17.5%) of C. glauca under severe drought, while decreasing the root biomass and total biomass in C. lanceolata. The biomass allocation patterns of C. lanceolata and C. glauca were altered by nitrogen addition under drought. The response of biomass allocation of C. glauca to nitrogen was different under different water conditions, and the fertilizer efficiency was stronger in moderate drought than that during severe drought. Nitrogen addition increased the stem biomass ratio, leaf biomass ratio, and stem leaf ratio of C. lanceolata under the same water treatment, while root biomass ratio (19.4% and 30.0%) and specific root length (39.8% and 28.5%) and root top ratio (28.3% and 38.1%) were significantly reduced under moderate and severe drought (P<0.05). Nitrogen addition significantly inhibited the root length, root surface area and root volume of each diameter grades of C. lanceolata in the drought stress (P<0.05), especially under moderate drought. However, nitrogen showed a positive effect on the root growth and morphology of C. glauca under severe drought. Taken together, the biomass production and root morphology of C. lanceolata and C. glauca seedlings differed in responses to drought after nitrogen addition. Nitrogen application had no positive effect on the growth of C. lanceolata seedlings under drought stress, but C. lanceolata adjust its biomass allocation to alleviate damage caused by drought stress.

Key words: Cunninghamia lanceolata, Cyclobalanopsis glauca, nitrogen, drought, biomass, root morphology

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