Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environment, China Agricultural University, Beijing, China.
Ann Bot. 2011 Apr;107(5):793-803. doi: 10.1093/aob/mcq223. Epub 2010 Nov 22.
Many indeterminate plants can have wide fluctuations in the pattern of fruit-set and harvest. Fruit-set in these types of plants depends largely on the balance between source (assimilate supply) and sink strength (assimilate demand) within the plant. This study aims to evaluate the ability of functional-structural plant models to simulate different fruit-set patterns among Capsicum cultivars through source-sink relationships.
A greenhouse experiment of six Capsicum cultivars characterized with different fruit weight and fruit-set was conducted. Fruit-set patterns and potential fruit sink strength were determined through measurement. Source and sink strength of other organs were determined via the GREENLAB model, with a description of plant organ weight and dimensions according to plant topological structure established from the measured data as inputs. Parameter optimization was determined using a generalized least squares method for the entire growth cycle.
Fruit sink strength differed among cultivars. Vegetative sink strength was generally lower for large-fruited cultivars than for small-fruited ones. The larger the size of the fruit, the larger variation there was in fruit-set and fruit yield. Large-fruited cultivars need a higher source-sink ratio for fruit-set, which means higher demand for assimilates. Temporal heterogeneity of fruit-set affected both number and yield of fruit. The simulation study showed that reducing heterogeneity of fruit-set was obtained by different approaches: for example, increasing source strength; decreasing vegetative sink strength, source-sink ratio for fruit-set and flower appearance rate; and harvesting individual fruits earlier before full ripeness. Simulation results showed that, when we increased source strength or decreased vegetative sink strength, fruit-set and fruit weight increased. However, no significant differences were found between large-fruited and small-fruited groups of cultivars regarding the effects of source and vegetative sink strength on fruit-set and fruit weight. When the source-sink ratio at fruit-set decreased, the number of fruit retained on the plant increased competition for assimilates with vegetative organs. Therefore, total plant and vegetative dry weights decreased, especially for large-fruited cultivars. Optimization study showed that temporal heterogeneity of fruit-set and ripening was predicted to be reduced when fruits were harvested earlier. Furthermore, there was a 20 % increase in the number of extra fruit set.
许多不定型植物的果实结实和收获模式波动很大。这些类型植物的结实很大程度上取决于植物内源（同化供应）和汇（同化需求）之间的平衡。本研究旨在通过源-汇关系评估功能结构植物模型模拟不同辣椒品种果实结实模式的能力。
对具有不同果实重量和果实结实率的六个辣椒品种进行温室试验。通过测量确定果实结实模式和潜在果实汇强度。其他器官的源和汇强度通过 GREENLAB 模型确定，根据从测量数据中建立的植物拓扑结构描述植物器官的重量和尺寸作为输入。使用整个生长周期的广义最小二乘法确定参数优化。
品种间果实汇强度存在差异。大果品种的营养体汇强度通常低于小果品种。果实越大，果实结实和产量的变化越大。大果品种结实需要更高的源-汇比，这意味着对同化产物的需求更高。果实结实的时间异质性影响果实的数量和产量。模拟研究表明，通过不同的方法可以减少果实结实的异质性：例如，增加源强度；降低营养体汇强度、结实期源-汇比和开花率；以及在完全成熟前更早地收获个别果实。模拟结果表明，当我们增加源强度或降低营养体汇强度时，果实结实和果实重量增加。然而，在源和营养体汇强度对果实结实和果实重量的影响方面，大果和小果品种组之间没有发现显著差异。当结实期源-汇比降低时，保留在植物上的果实数量增加，与营养器官争夺同化产物。因此，总植物和营养体干重减少，尤其是大果品种。优化研究表明，当果实更早收获时，预测果实结实和成熟的时间异质性会降低。此外，额外果实的数量增加了 20%。
