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不同林龄红锥人工林细根垂直分布和衰老生理特征

吴敏1,邓平1,2*,赵英1,钟道发1,曾令鑫1   

  1. 1玉林师范学院, 桂东南珍稀经济物种保护利用重点实验室培育基地, 广西玉林 537000;2西北农林科技大学, 陕西杨凌 712100)
  • 出版日期:2019-09-10 发布日期:2019-09-10

Vertical distribution and physiological senescence characteristics of fine roots in Castanopsis hystrix Miq. plantations at different ages.

WU Min1, DENG Ping1,2*, ZHAO Ying1, ZHONG Dao-fa1, ZENG Ling-xin1   

  1. (1Yulin Normal University, Key Laboratory Breeding Base for the Protection and Utilization of Rare Economic Species in Southeastern Guangxi, Yulin 537000, Guangxi, China; 2Northwest A&F University, Yangling 712100, Shaanxi, China).
  • Online:2019-09-10 Published:2019-09-10

摘要: 以广西桂东和桂南地区3种林龄(7、14和25 a)红锥人工林细根为对象,在红锥生长旺季,采用根钻法,分表层(0~20 cm)和亚表层土壤(20~40 cm)获取细根,研究不同林龄红锥人工林细根在不同土层的形态、生物量以及衰老生理生化指标变化特征,以期深入认识红锥生长发育机制及林分生产力,为红锥人工林可持续经营提供依据。结果表明:在相同土层中,随林龄增加,红锥细根根长密度、根表面积密度、生物量、比表面积、细根活力、可溶性糖和可溶性蛋白含量均显著增加,而比根长、游离脯氨酸和丙二醛(MDA)含量显著减少;在相同林龄下,随土壤深度增加,红椎细根比根长、比表面积、细根活力、各渗透调节物质含量均显著增加,而根长密度、表面积密度、生物量、MDA含量显著减少;林龄和土层的交互作用对细根生物量、可溶性糖、可溶性蛋白和MDA含量有显著影响。细根根长密度、根表面积密度和生物量与各土壤因子间呈显著正相关;细根游离脯氨酸含量与各土壤因子间呈显著负相关;细根活力、可溶性糖和可溶性蛋白仅与土壤含水率、速效氮呈显著正相关。因此,7 a红锥细根易衰老,更新快,14 a林次之,25 a林细根更新慢;表层土(0~20 cm)的红锥细根代谢旺盛,周转速率快,寿命较短。

关键词: 低温, 光周期, 西藏飞蝗

Abstract:

The vertical distribution, morphology, biomass and aging physiological indicators of fine roots of Castanopsis hystrix Miq.in different ages (7, 14 and 25 years old) and soil depths (0-20 and 20-40 cm) were examined using soil coring method, to better understand the tree growth and development and thus provide scientific basis for sustainable management of C. hystrixplantations. C. hystrixplantations were selected in the Guidong and Guinan, Guangxi Zhuang Autonomous Region. The results showed that fine root length density, root surface area density, biomass, specific surface area, vigor and the contents of soluble sugar and soluble protein of fine roots in the same soil layer significantly increased with the increases of stand age, while specific root length, the contents of free proline and malondialdehyde (MDA) of fine roots significantly reduced. Under the same stand age, specific root length, specific surface area, vigor and the content of osmotic adjustment substances of fine roots enhanced with increasing soil depth, while root length density, root surface area density, biomass and MDA content of fine roots significantly decreased. The interaction between stand age and soil layer had a significant effect on biomass, the contents of soluble sugar, soluble protein and MDA of fine roots. There were significant positive correlations between root length density, root surface area density and fine root biomass and soil factors. In contrast, a significant negative correlation was found for free proline content of fine roots and soil factors. Meanwhile, vigor, soluble sugar and soluble protein content of fine roots were significantly positively correlated with soil water content and available nitrogen concentration. Fine roots of young forest (7 years old) were more prone to senescence, followed by 14 years old stand, and then 25 years old stand. Furthermore, fine roots in the topsoil (0-20 cm) had high metabolism, fast turnover rate and short lifespan.
 

Key words: low temperature, photoperiod,  , Locusta migratoria tibetensis.