植物生态学报

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杉木幼苗生物量分配格局对氮添加的响应

王娇,关欣,张伟东,黄苛,朱睦楠,杨庆朋   

  1. 中国科学院沈阳应用生态研究所
  • 收稿日期:2021-04-09 修回日期:2021-08-29 发布日期:2021-09-18
  • 通讯作者: 杨庆朋
  • 基金资助:
    国家自然科学基金项目;国家自然科学基金项目;国家自然科学基金项目

Responses of biomass allocation patterns to nitrogen addition in Cunninghamia lanceolata seedlings

1,Xin GUAN1, 2,Ke HUANG1,Mu-Nan ZHU1, 2   

  1. 1. Institute of Applied Ecology, Chinese Academy of Sciences
    2.
  • Received:2021-04-09 Revised:2021-08-29 Published:2021-09-18
  • Supported by:
    National Natural Science Foundation of China;National Natural Science Foundation of China;National Natural Science Foundation of China

摘要: 大气氮(N)沉降的急剧增加可能会对植物碳(C)固定和分配产生深远影响。然而, N添加如何影响碳水化合物在植物不同器官之间的分配动态并不十分清楚。该研究利用杉木幼苗盆栽试验, 设置氮添加处理, 测定分析幼苗非结构性碳水化合物(NSC)与结构性碳水化合物(SC)浓度和库的变化, 以探讨N添加后杉木(Cunninghamia lanceolata)幼苗不同器官中NSC与SC的分配模式及调控机制。结果发现: (1) N添加虽然显著增加叶片净光合速率(143.96%), 但却降低了叶片中的NSC浓度和含量; N添加导致一年生茎的淀粉含量显著下降, 而可溶性糖含量的变化不显著, 当年生茎的NSC组分没有显著变化; 幼苗根系的NSC含量及其组分也有降低的趋势。(2) N添加后地下与地上生物量的比值降低22.09%, 其中SC含量降低31.07%, 而NSC含量无显著变化。(3) N添加使地上部分的P含量显著增加, 使地下与地上P含量的比值降低了57.02%, 而N库的比值无显著变化。(4) N添加后土壤pH由(4.94 ± 0.09)显著降低到(4.02 ± 0.04), 铵态N和硝态N分别增加7.17倍和11.55倍, 土壤有效P含量也增加了42.86%, 而土壤中脲酶(62.75%)和酸性磷酸酶(56.52%)的活性显著降低。研究表明, 低养分条件下杉木幼苗主要通过构建根系结构增加养分吸收, 而非通过向根系分配更多的NSC, 而N添加驱动的养分缓解使更多的碳水化合物分配到地上器官, 导致地上部分SC积累。

关键词: 氮添加, 生物量分配, 碳水化合物, 非结构性碳, 磷, 最优分配理论

Abstract: Aims Sharply increased atmospheric nitrogen (N) deposition may have profound effects on carbon (C) fixation and allocation of plants. However, a comprehensive understanding of how nitrogen addition influences allocation dynamics of carbohydrates among different organs in plants. Methods This study, which was based on a pot experiment of seedlings of Cunninghamia lanceolate, investigated the allocation pattern and regulation mechanism of non-structural carbohydrates (NSC) and structural carbohydrates (SC) in different organs of C. lanceolate seedlings after N addition. The concentration and pool size of NSC and SC of seedlings were measured. Important findings The results showed that: (1) N addition could significantly increase the net photosynthetic rate by 143.96%, but decreased the concentration and pool size of NSC in needles. There was no significant change in the components of NSC in current-year stems. Furthermore, N addition resulted in a significant decrease in the starch content of one-year-old stems, but no significant change in soluble sugar content. In addition, the components of NSC in seedlings roots also tended to decrease. (2) After N addition, the ratio of under- to above-ground biomass decreased by 22.09%, and the ratio of SC also decreased by 31.07%, and the ratio of NSC showed no significantly difference between control and N addition treatment. (3) N addition significantly increased the phosphorus (P) pool in the above-ground part and decreased the ratio of under- to above-ground P pool, while the ratio of N pool showed no obvious change between control and N addition treatment. (4) Under N addition, soil pH decreased significantly from 4.94 to 4.02, ammonium and nitrate nitrogen content increased by 7.17 times and 11.55 times, respectively, and soil available P content increased by 42.86%, while the activities of urease (62.75%) and acid phosphatase (56.52%) in the soil decreased significantly. Our results indicates that C. lanceolate seedlings increased nutrient uptake mainly by the construction of root structure, not by the allocation of more NSC to the root under low nutrient conditions, while nutrient alleviation driven by nitrogen addition resulted in more carbohydrates allocation to above-ground organs, so the accumulation of SC in above-ground parts.

Key words: nitrogen addition, biomass allocation, carbohydrates, non-structural carbohydrates, phosphorus, optimal partitioning theory