Effects of Shading on the Growth and Photosynthetic Fluorescence Characteristics of <i>Castanopsis hystrix</i> Seedlings of Top Community-Building Species in Southern Subtropical China
<i>Castanopsis hystrix</i> is a major community-building species in the top communities of southern subtropical China, with a high natural regeneration capacity. However, excessive logging and the introduction of exotic tree species have substantially reduced the area of natural forest p...
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MDPI AG
2023-08-01
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| Series: | Forests |
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| Online Access: | https://www.mdpi.com/1999-4907/14/8/1659 |
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| author | Guangyu Xue Junduo Wu Bingjiang Zhou Xueping Zhu Ji Zeng Yue Ma Yanan Wang Hongyan Jia |
| author_facet | Guangyu Xue Junduo Wu Bingjiang Zhou Xueping Zhu Ji Zeng Yue Ma Yanan Wang Hongyan Jia |
| author_sort | Guangyu Xue |
| collection | DOAJ |
| description | <i>Castanopsis hystrix</i> is a major community-building species in the top communities of southern subtropical China, with a high natural regeneration capacity. However, excessive logging and the introduction of exotic tree species have substantially reduced the area of natural forest patches of <i>Castanopsis hystrix</i>, and seedling regeneration is essential for the long-term continuation of <i>Castanopsis hystrix</i> populations. To explore the effects of light intensity on the seedling emergence and early growth of <i>Castanopsis hystrix</i>, shading experiments were conducted under four shading treatments (0%, 40%, 60%, and 80%). The growth, biomass accumulation, and distribution, the quality index of seedlings, the morphology and structure of the root systems of seedlings, and the leaf chlorophyll content and chlorophyll fluorescence properties of seedlings under different shading treatments were analyzed. The results displayed the following: (1) Shade intensity impacts growth of <i>Castanopsis hystrix</i> seedlings and biomass allocation, with optimal results observed at 60% shade, leading to the promotion of organic matter production in leaves and the limitation of stem growth. (2) Using a multi-indicator composite index, it was determined that seedling quality for <i>Castanopsis hystrix</i> peaks at 60% shade intensity. (3) Shade significantly impacts the morphology and structure of <i>Castanopsis hystrix</i>’s root system, with most root characteristics peaking at 60% shade, indicating a substantial increase in root development compared to no-shade conditions. (4) The D-values indicated the most suitable shade intensity for seedling growth to be 60%, suggesting that <i>Castanopsis hystrix</i> seedlings are sensitive to light and excessive light can be detrimental to their growth. (5) The 60% shade treatment showed the maximum values of chlorophyll fluorescence characteristics and photochemical activity, with variations in energy conversion efficiency and dissipation reflected in parameters like photochemical burst coefficient (qP), photochemical burst coefficient (qN), the actual photometric yield of PSII under light acclimation (YII), and the maximum photosynthetic electron transport rate in photoinhibition (ETR), thereby supporting seedling growth and maintaining the normal function of photosynthetic organs. In conclusion, 60% shade treatment can effectively improve the growth and photosynthetic characteristics of <i>Castanopsis hystrix</i> seedlings and promote the accumulation of nutrient elements, ultimately promoting their growth. |
| first_indexed | 2024-03-10T23:55:58Z |
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| id | doaj.art-18d53f8ee76149bb8b5d59ffe412675c |
| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-10T23:55:58Z |
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| spelling | doaj.art-18d53f8ee76149bb8b5d59ffe412675c2023-11-19T01:10:10ZengMDPI AGForests1999-49072023-08-01148165910.3390/f14081659Effects of Shading on the Growth and Photosynthetic Fluorescence Characteristics of <i>Castanopsis hystrix</i> Seedlings of Top Community-Building Species in Southern Subtropical ChinaGuangyu Xue0Junduo Wu1Bingjiang Zhou2Xueping Zhu3Ji Zeng4Yue Ma5Yanan Wang6Hongyan Jia7Experimental Centre of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, ChinaExperimental Centre of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, ChinaExperimental Centre of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, ChinaExperimental Centre of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, ChinaExperimental Centre of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, ChinaExperimental Centre of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, ChinaExperimental Centre of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, ChinaExperimental Centre of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, China<i>Castanopsis hystrix</i> is a major community-building species in the top communities of southern subtropical China, with a high natural regeneration capacity. However, excessive logging and the introduction of exotic tree species have substantially reduced the area of natural forest patches of <i>Castanopsis hystrix</i>, and seedling regeneration is essential for the long-term continuation of <i>Castanopsis hystrix</i> populations. To explore the effects of light intensity on the seedling emergence and early growth of <i>Castanopsis hystrix</i>, shading experiments were conducted under four shading treatments (0%, 40%, 60%, and 80%). The growth, biomass accumulation, and distribution, the quality index of seedlings, the morphology and structure of the root systems of seedlings, and the leaf chlorophyll content and chlorophyll fluorescence properties of seedlings under different shading treatments were analyzed. The results displayed the following: (1) Shade intensity impacts growth of <i>Castanopsis hystrix</i> seedlings and biomass allocation, with optimal results observed at 60% shade, leading to the promotion of organic matter production in leaves and the limitation of stem growth. (2) Using a multi-indicator composite index, it was determined that seedling quality for <i>Castanopsis hystrix</i> peaks at 60% shade intensity. (3) Shade significantly impacts the morphology and structure of <i>Castanopsis hystrix</i>’s root system, with most root characteristics peaking at 60% shade, indicating a substantial increase in root development compared to no-shade conditions. (4) The D-values indicated the most suitable shade intensity for seedling growth to be 60%, suggesting that <i>Castanopsis hystrix</i> seedlings are sensitive to light and excessive light can be detrimental to their growth. (5) The 60% shade treatment showed the maximum values of chlorophyll fluorescence characteristics and photochemical activity, with variations in energy conversion efficiency and dissipation reflected in parameters like photochemical burst coefficient (qP), photochemical burst coefficient (qN), the actual photometric yield of PSII under light acclimation (YII), and the maximum photosynthetic electron transport rate in photoinhibition (ETR), thereby supporting seedling growth and maintaining the normal function of photosynthetic organs. In conclusion, 60% shade treatment can effectively improve the growth and photosynthetic characteristics of <i>Castanopsis hystrix</i> seedlings and promote the accumulation of nutrient elements, ultimately promoting their growth.https://www.mdpi.com/1999-4907/14/8/1659shading<i>Castanopsis hystrix</i>biomass allocationroot characteristicschlorophyll fluorescence characteristics |
| spellingShingle | Guangyu Xue Junduo Wu Bingjiang Zhou Xueping Zhu Ji Zeng Yue Ma Yanan Wang Hongyan Jia Effects of Shading on the Growth and Photosynthetic Fluorescence Characteristics of <i>Castanopsis hystrix</i> Seedlings of Top Community-Building Species in Southern Subtropical China Forests shading <i>Castanopsis hystrix</i> biomass allocation root characteristics chlorophyll fluorescence characteristics |
| title | Effects of Shading on the Growth and Photosynthetic Fluorescence Characteristics of <i>Castanopsis hystrix</i> Seedlings of Top Community-Building Species in Southern Subtropical China |
| title_full | Effects of Shading on the Growth and Photosynthetic Fluorescence Characteristics of <i>Castanopsis hystrix</i> Seedlings of Top Community-Building Species in Southern Subtropical China |
| title_fullStr | Effects of Shading on the Growth and Photosynthetic Fluorescence Characteristics of <i>Castanopsis hystrix</i> Seedlings of Top Community-Building Species in Southern Subtropical China |
| title_full_unstemmed | Effects of Shading on the Growth and Photosynthetic Fluorescence Characteristics of <i>Castanopsis hystrix</i> Seedlings of Top Community-Building Species in Southern Subtropical China |
| title_short | Effects of Shading on the Growth and Photosynthetic Fluorescence Characteristics of <i>Castanopsis hystrix</i> Seedlings of Top Community-Building Species in Southern Subtropical China |
| title_sort | effects of shading on the growth and photosynthetic fluorescence characteristics of i castanopsis hystrix i seedlings of top community building species in southern subtropical china |
| topic | shading <i>Castanopsis hystrix</i> biomass allocation root characteristics chlorophyll fluorescence characteristics |
| url | https://www.mdpi.com/1999-4907/14/8/1659 |
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