Distribution of photosynthetic assimilates to organs in first-fruiting walnuts on the whole-plant scale

doi:10.6048/j.issn.1001-4330.2025.06.018

Abstract

Abstract:

【Objective】 To clarify the characteristics of leaf photosynthetic assimilate partitioning to fruit in Wen185 walnut (J. regia Wen185). 【Methods】 In this study, we used the ¹³C isotope pulse labeling technique to label the whole plant of 5-year-old walnut trees and analyzed the changes in the rate of ¹³C partitioning (R¹³C), leaf source strength, and fruit pool strength in fruits and leaves during different fruit development periods. 【Results】 R¹³C gradually decreased in leaves and maintained at a high level from 40 to 60 d after anthesis; R¹³C showed a 'rise-fall-rise-fall' change in fruits, and significantly increased from 40 to 60 d and from 80 to 100 d after anthesis (P<0.05); chlorophyll content and Rubisco carboxylase activity in leaves showed a 'rise to fall' change, and net photosynthetic rate showed a 'rise-fall-rise-fall' change, both of which were significantly higher at 40 to 60 d after flowering (P<0.05); fruit weight and volume both increased significantly at 40 to 60 d and 80 to 100 d after flowering increased (P<0.05). 【Conclusion】 From 40 to 60 d after flowering, most of the photosynthetic assimilates are used for the rapid growth of leaves, and the rapid growth of leaves is accompanied by the elevation of photosynthetic capacity, at which time the leaves complete the transformation from reservoir to source; from 40 to 60 d after flowering, and from 80 to 100 d, which are the two periods with more allocation of photosynthetic assimilates to the fruits, in which the fruits are growing rapidly from 40 to 60 d after flowering, and the reservoir strength is elevated, and photosynthetic assimilates are mainly used for fruit cell division and morphology construction. In the period from 40 to 60 d after flowering, the fruit grew rapidly and the reservoir strength increased, and the photosynthetically assimilated substances are mainly used for fruit cell division and morphology construction.

Key words: walnut; photosynthetic assimilates; ¹³C isotope labeling; source strength; sink strength

摘要：

【目的】研究温185核桃(J. regia Wen185)叶片光合同化物向果实分配的特性。【方法】采用¹³C同位素脉冲标记技术对5年生核桃树全株进行标记,分析核桃不同果实发育时期果实、叶片和其他器官中¹³C分配率(R¹³C)、叶片源强和果实库强的变化。【结果】R¹³C在叶片中逐渐降低,在花后40~60 d维持在较高水平;R¹³C在果实中呈‘升-降-升-降’的变化,在花后40~60 d和80~100 d显著升高(P<0.05);叶片中叶绿素含量和Rubisco羧化酶活性呈‘升-降’的变化,净光合速率呈‘升-降-升-降’的变化,均在花后40~60 d显著升高(P<0.05);果实重量和体积均在花后40~60 d和80~100 d显著上升(P<0.05)。【结论】花后40~60 d,大部分光合同化物用于叶片的快速生长,叶片的快速生长伴随着光合能力的升高,此时叶片完成从库到源的转变;花后40~60 d,和80~100 d,是光合同化物向果实分配较多的两个时期,其中花后40~60 d果实迅速生长,库强提高,光合同化物主要用于果实细胞分裂和形态构建,花后80~100 d时果实处于油脂转化期,库强提高,促进光合同化物向果实的分配。

关键词: 核桃, 光合同化物, ¹³C同位素标记, 源强, 库强

CLC Number:

S664.1

HAO Honglong, ZHANG Cuifang, WANG Shiwei, YANG Xianan, GUO Tong, GENG Zhaokun, ZHAO Long, LI Zhenyu. Distribution of photosynthetic assimilates to organs in first-fruiting walnuts on the whole-plant scale[J]. Xinjiang Agricultural Sciences, 2025, 62(6): 1461-1468.

郝洪龙, 张翠芳, 王世伟, 杨先安, 郭桐, 耿召坤, 赵龙, 李振瑜. 整株尺度上核桃初果期光合同化物向果实的分配特性[J]. 新疆农业科学, 2025, 62(6): 1461-1468.

Figures/Tables 4

Fig.1 R13C changes in leaves and fruits of walnut during different fruit development periods Notes: Different lowercase letters indicate significant differences (P<0.05) at the 0.05 level between different organs at the same time point;Different uppercase letters indicate significant differences (P<0.05) at the 0.05 level between different time points for the same organ

Fig.2 Changes in leaf source strength at different stages of fruit development Notes: Different lowercase letters represent significant differences at the 0.05 level in different periods for the same indicator (P< 0.05)

Fig.3 Changes in single fruit weight, volume, sucrose content and acid invertase activity of walnut fruits during different periods of fruit development Notes: Different lowercase letters represent significant differences at the 0.05 level in different periods for the same indicator (P< 0.05)

Fig.4 Correlation matrix of fruit R13C, leaf R13C and each index of source and reservoir strength at different developmental periods Notes: Pn is net photosynthetic rate, Fv/Fm is potential light quantum coefficient of PSII, ISFW is net increase in weight of single fruit, and IFV is net increase in volume of single fruit.Absolute values above 0.8 indicate highly significant correlations at the 0.01 level; absolute values between 0.5 and 0.8 indicate significant correlations at the 0.05 level

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