马尾松幼苗光合产物的运输与分配特征

【目的】解析光合产物在马尾松幼苗植株中的运输和分配规律,揭示马尾松生产力形成过程,为探讨不同环境干扰下马尾松光合产物分配过程的变化提供参考依据。【方法】采用 13 C同位素脉冲标记法,对1.5年生马尾松幼苗进行标记,标记结束后第0、2、5、17、24、72、120、168、216和 360 h ,按不同部位对马尾松幼苗进行全收获取样,测定 13 C含量,以监测近期合成的光合产物在马尾松幼苗中的运输和分配规律,同时测定光合产物全碳、非结构性碳水化合物(NSC)在各个器官的积累量。【结果】1)标记的光合产物在针叶中合成后,向各库器官的运输量随着时间延长由多逐渐减少,具体表现为标记结束后0~24 h内最多,24~216 h逐渐减少,216 h之后运输完成,且59%以上标记的光合产物在0~24 h内运输到各库器官。2)光合产物运输趋于稳定后,在各器官的分配大小依次为1年生叶>当年生叶>根>茎干>1年生枝>当年生枝,与生物量的分配大小一致,但与库活力大小不同,其库活力依次为当年生叶>当年生枝>1年生叶>根>1年生枝>茎干。3)各器官全碳和NSC积累量的分配与近期合成光合产物的分配大小一致,依次为1年生叶>当年生叶>根>茎干>1年生枝>当年生枝。【结论】马尾松幼苗光合产物运输速率大于0.1 m ·h -1 ,59%以上标记的光合产物在合成后的0~ 24 h 内完成向各个库器官输出。新合成的光合产物在各器官中的积累量表现为功能器官(叶和根)居多,这一分配规律有利于马尾松幼苗阶段的生长。

Transport and Distribution Characteristics of Photosynthates of Pinus massoniana Seedlings

【Objective】 This study aimed to understand the pattern of transport and distribution of photosynthates in Pinus massoniana and the formation process of P. massoniana productivity.【Method】 In this study, the 1.5-year-old P. massoniana seedlings were fed with pulse-chased 13 C labeling for 4 h, and then the different organs were collected at 0, 2, 5, 17, 24, 72, 120, 168, 216 and 360 h to analyze the 13 C levels, to investigate the transport and distribution of recently synthesized photosynthates in the seedlings. Meanwhile, the accumulation of photosynthates(total carbon and non-structural carbohydrate (NSC)) was determined in various organs.【Result】 1) After the labeled photosynthetic products were synthesized in conifers, the labeled photosynthates were found to be transported to the sink organs, however the amount of the transportation gradually decreased with time. It was manifested that most of the photosynthates were transported within 0-24 hours after the labeling, and the transportation was decreased gradually from 24 to 216 hours. In 216 hours, the labeled photosynthates finished outward transport. It was found that more than 59% of the labeled photosynthates were transported to the sink organs within 0-24 hours over the period of 216 hours. 2) After the transport of photosynthates tended to stable, the distribution of recently synthesized photosynthates in each organ was in the order of 1-year leaves> current-year leaves>roots>stem>1-year branches> current-year branches, which was consistent with the distribution of the biomass, but different from the sink activity, the sink activity was ordered as current-year leaves> current-year branches>1-year leaves> roots>1-year branches>stem. 3) The distribution of total carbon and NSC accumulation in various organs was in accordance with the distribution of recently synthetic photosynthates, which was ordered as 1-year leaves>current-year leaves>roots>stem>1-year branches>current-year branches.【Conclusion】 The photosynthates transport rate in P. massoniana seedlings was greater than 0.1 m ·h -1 , and more than 59% labeled photosynthates were exported to all sink organs within 0-24 hours after synthesis. The accumulation of new synthesized photosynthates in various organs was mostly in functional organs (leaves and roots). This distribution pattern is conducive to the growth of P. massoniana at seedling stage.