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Zhu J, Jiang L, Chen L, Jin X, Xing C, Liu J, Yang Y, He Z. Tree seedling growth allocation of Castanopsis kawakamii is determined by seed-relative positions. FRONTIERS IN PLANT SCIENCE 2023; 14:1099139. [PMID: 37332687 PMCID: PMC10272420 DOI: 10.3389/fpls.2023.1099139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 05/10/2023] [Indexed: 06/20/2023]
Abstract
Plants allocate growth to different organs as a strategy to obtain limiting resources in different environments. Tree seeds that fall from a mother tree settle on, within, or below the forest floor and litter layer, and their relative positions can determine seedling biomass and nutrient allocation and ultimately affect survival to the sapling stage. However, how emerged seedling biomass and nutrients of each organ are affected by seeds in different positions is not yet completely understood in subtropical forests. Therefore, an experiment was conducted with seeds positioned above the litter layers of different thicknesses, on the forest floor, and beneath the litter layer, and the influences of seed position on biomass allocation and nutrient use efficiency of emerged seedlings of Castanopsis kawakamii was examined. The aim of the study was to determine the optimal seed position to promote regeneration. Allocation strategies were well coordinated in the emerged seedlings from different seed positions. Seedlings from seeds positioned above litter layers of different thicknesses (~40 and 80 g of litter) allocated growth to leaf tissue at the expense of root tissue (lower root mass fraction) and increased nitrogen (N) and phosphorus (P) accumulation and nutrient use efficiency. Seedlings from seeds positioned beneath a deep litter layer allocated most growth to roots (high root: shoot ratio, root mass fraction) to capture available resources at the expense of leaf growth. Seedlings from seeds positioned on the forest floor allocated most growth to roots to obtain limiting resources. Further, we also found that these traits were clustered into three groups based on trait similarity, and the cumulative interpretation rate was 74.2%. Thus, seed relative positions significantly affected seedling growth by altering the allocation of resources to different organs. The different strategies indicated that root N:P ratios (entropy weight vector was 0.078) and P nutrient use efficiency were essential factors affecting seedling growth in the subtropical forest. Of the seed positions analyzed, beneath a moderate litter layer (~40 g of litter) was the most suitable position for the growth and survival of Castanopsis seedlings. In future studies, field and lab experiments will be combined to reveal the mechanisms underlying forest regeneration.
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Affiliation(s)
- Jing Zhu
- Key Laboratory of Fujian Universities for Ecology and Resource Statistics, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lan Jiang
- Key Laboratory of Fujian Universities for Ecology and Resource Statistics, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lyuyi Chen
- Entomology and Nematology Department, University of Florida, Gainesville, FL, United States
| | - Xing Jin
- Key Laboratory of Fujian Universities for Ecology and Resource Statistics, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Cong Xing
- Key Laboratory of Fujian Universities for Ecology and Resource Statistics, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jinfu Liu
- Key Laboratory of Fujian Universities for Ecology and Resource Statistics, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yongchuan Yang
- College of Environment and Ecology, Chongqing University, Chongqing, China
| | - Zhongsheng He
- Key Laboratory of Fujian Universities for Ecology and Resource Statistics, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
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Lyu Q, Luo Y, Liu S, Zhang Y, Li X, Hou G, Chen G, Zhao K, Fan C, Li X. Forest gaps alter the soil bacterial community of weeping cypress plantations by modulating the understory plant diversity. FRONTIERS IN PLANT SCIENCE 2022; 13:920905. [PMID: 36061809 PMCID: PMC9437579 DOI: 10.3389/fpls.2022.920905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
Weeping cypress is an endemic tree species that is widely planted in China, and the simple stand structure and fragile ecosystem of its plantation are common issues. Exploring the effect of different gap sizes on the soil bacterial community structure of weeping cypress plantations can provide a theoretical basis for the near-natural management of forest plantations. We, therefore, constructed three kinds of forest gaps with different sizes in weeping cypress plantations, namely, small (50-100 m2), medium (100-200 m2), and large gaps (400-667 m2), for identifying the key factors that affect soil bacterial communities following the construction of forest gaps. The results suggested that the herb layer was more sensitive than the shrub layer, while the Simpson, Shannon, and richness indices of the herb layer in plots with gaps were significantly higher than those of designated sampling plots without any gaps (CK). The presence of large gaps significantly increased the understory plant diversity and the Shannon and Simpson indices of the soil bacterial alpha diversity. There were obvious changes in the community composition of soil bacteria following the construction of forest gaps. The dominant bacterial phyla, orders, and functions were similar across the plots with different gap sizes. Of the indicator bacterial species, the abundance of the nitrogen-fixing bacteria, Lysobacter_ yangpyeongensis, and Ensifer_meliloti, was significantly different across plots with different gap sizes and accounted for a large proportion of the bacterial population of plots with medium and large gaps. The understory plant diversity was mostly related to the soil bacterial community than to other soil factors. The results of structural equation modeling indicated that the understory plant diversity was the most important environmental factor in driving the composition and diversity of bacterial communities. The construction of forest gaps significantly improved the understory plant diversity, physicochemical properties of the soil, and bacterial diversity in weeping cypress plantations, and the results of the comprehensive evaluation were in the order: large gaps > small gaps > medium gaps > CK. Our results suggested that large gaps are beneficial for the diversity of above-ground plant communities and underground soil bacterial communities.
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Affiliation(s)
- Qian Lyu
- College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Yan Luo
- College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Size Liu
- Sichuan Academy of Forestry, Chengdu, China
| | - Yan Zhang
- College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Xiangjun Li
- College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Guirong Hou
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Gang Chen
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Kuangji Zhao
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Chuan Fan
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Xianwei Li
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
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