| 摘要: |
| 【目的】探究楠木幼苗对不同光照强度及硅肥的生理响应特征，为楠木林下更新及混交造林提供理论依据。【方法】以楠木1年生幼苗为研究对象，采用黑尼龙网布覆盖模拟相对光照强度分别为100%（全光照，CK），60%，40%，15%，5%的遮荫网室，将盆栽楠木幼苗移入不同相对光照强度遮荫网室中，分别添加0，1 000，2 000，4 000 mg/kg水溶性硅肥（SiO2含量≥50%），测定不同处理楠木幼苗的苗高增长量和地径增长量，分析处理早期（2021年8月，处理4个月）、中期（2021年12月，处理8个月）和晚期（2022年4月，处理12个月）不同处理楠木幼苗叶片生理指标（超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、可溶性糖、可溶性蛋白、丙二醛（MDA））的变化。【结果】在同一相对光照强度下，随着硅添加量的增加，楠木苗高增长量和地径增长量总体先上升后下降，在相对光照强度为15%~40%条件下添加1 000~2 000 mg/kg硅明显提高了楠木苗高增长量和地径增长量。处理早期，当硅添加量相同时，随着相对光照强度的降低，楠木幼苗叶片SOD、POD和CAT活性总体先下降后升高，可溶性糖、可溶性蛋白和MDA含量总体先升高后下降；处理中期，当硅添加量相同时，随着相对光照强度的降低，楠木幼苗叶片SOD、POD活性和可溶性糖含量总体先升高后下降，CAT活性和MDA含量总体先下降后升高, 可溶性蛋白含量无明显变化规律；处理晚期，当硅添加量相同时，随着相对光照强度的降低，楠木幼苗叶片SOD、POD和CAT活性和可溶性糖、可溶性蛋白含量总体先升高后下降，MDA含量总体先下降后升高。在处理早期、中期和晚期，在同一光照强度下，随着硅添加量的增加，楠木幼苗叶片生理指标有明显差异。在相对光照强度为5%~40%条件下,添加1 000~2 000 mg/kg硅明显提高了楠木幼苗叶片SOD和CAT活性；在不同相对光照强度下添加1 000~2 000 mg/kg硅总体明显提高了楠木幼苗叶片可溶性糖含量。在相对光照强度为5%~15%条件下,添加2 000 mg/kg硅可明显提高楠木幼苗的可溶性蛋白含量。在相对光照强度为15%~40%条件下,添加1 000~4 000 mg/kg硅可明显降低幼苗叶片MDA含量。【结论】不同相对光照强度下硅对楠木幼苗生长及叶片生理指标有明显影响。适当遮荫有利于楠木幼苗的生长，且在此基础上添加硅肥将进一步提高楠木幼苗应对光照胁迫的适应性，有利于楠木林的更新。 |
| 关键词: 楠木幼苗 光照强度 硅肥 叶片生理指标 林下更新 |
| DOI：DOI:10.13207/j.cnki.jnwafu.2024.12.004 |
| 分类号: |
| 基金项目:福建省自然科学基金面上项目（2023J011419）；国家自然科学基金面上项目（32071760） |
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| Physiological responses of Phoebe bournei seedlings to different light intensities and silicon fertilizer applications |
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LIAO Xiaoli1, CAI Siying2, LI Peiyao2, XUE Kexin2, LIN Junyi2, XIONG Houshui3, HUANG Wei4, JIN Shaofei1, ZHENG Dexiang2
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1.College of Geography and Oceanography,Minjiang University,Fuzhou,Fujian 350108,China;2.Forestry College,Fujian Agricultural and Forest University,Fuzhou,Fujian 350002,China;3.Stateowned Forest Farm of Shunchang,Shunchang,Fujian 353200,China;4.Forestry Bureau of Shunchang,Shunchang,Fujian 353200,China
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| Abstract: |
| 【Objective】To provide a theoretical basis for regenerating Phoebe bournei understory and mixed forestation,the physiological response characteristics of P. bournei seedlings to different light intensities and silicon fertilization were investigated.【Method】As the study subjects,one-year-old P. bournei seedlings were transplanted into pots and placed in shade net chambers with different relative light intensity levels of 100% (full light,CK),60%,40%,15% and 5% simulated by covering with black nylon nettings.Water-soluble silicon fertilizer (SiO2 content ≥50%) was added at 0,1 000,2 000 and 4 000 mg/kg levels,respectively.Height and diameter growths of P. bournei seedlings under different treatments were measured and physiological and biochemical indices including superoxide dismutase (SOD),peroxidase (POD),catalase (CAT),soluble sugars,soluble proteins and malondialdehyde (MDA) were determined.Changes in leaf physiological indexes under different treatments were analyzed across three periods of early stage (August 2021,the 4th month),middle stage (December 2021,the 8th month) and late stage (April 2022,the 12th month).【Result】Under same light intensities,height and diameter growths of P. bournei seedlings increased initially and then decreased with the increase of silicon addition.The addition of 1 000-2 000 mg/kg silicon significantly increased height and diameter growth of seedlings under relative light intensity of 15%-40%.At the early stage with same silicon additions, activity levels of SOD,POD and CAT enzymes in P. bournei seedling leaves generally decreased first and then increased with the decrease of light intensity.In contrast,contents of soluble sugar,soluble protein and MDA ge nerally increased first and then decreased.In the middle stage with same silicon amounts,SOD and POD activities as well as soluble sugar content in leaves of P. bournei seedlings generally increased initially and then decreased with the decrease of light intensity.Instead,CAT activity and MDA content generally decreased initially and then increased,while there was no clear pattern in soluble protein content.At the late stage with same silicon amounts,activities of SOD,POD and CAT and contents of soluble sugar and soluble protein in leaves generally increased first and then decreased,while MDA content showed opposite trend with the decrease of light intensity.Effects of silicon addition on physiological indexes of P. bournei seedling leaves were significant under same light intensities among three periods.When 1 000-2 000 mg/kg of silicon was added at 5%-40% light intensity,there were significant increases in SOD and CAT activities.Adding 1 000-2 000 mg/kg silicon overall significantly increased soluble sugar content.Soluble protein content was significantly increased by 2 000 mg/kg silicon at 5%-15% light intensities,while MDA content was significantly decreased by 1 000-4 000 mg/kg silicon addition at 15%-40% light intensities.【Conclusion】 Silicon addition had significant impacts on growth and leaf physiological indicators of P. bournei seedlings under different relative light intensities.Proper shading was beneficial for the growth of P. bournei seedlings and adding silicon fertilizer further enhanced the adaptability of P. bournei seedlings to light stress,which ultimately improved the regeneration of P. bournei forests. |
| Key words: Phoebe bournei seedlings light intensity silicon fertilizer leaf physiological indexes understory regeneration |
