Regulating carbon nitrogen ratio and key enzymes in sucrose metabolism: reducing fruit drop rate in sweet cherries

The research team led by Li Pengcheng from the Forestry Research Institute of Xinjiang Academy of Agricultural and Reclamation Sciences focuses on the early physiological fruit drop problem of sweet cherries, exploring the correlation between changes in carbon and nitrogen nutrition and sucrose metabolism enzyme activity during fruit development and fruit drop, providing theoretical support for optimizing cultivation, reducing fruit drop, and increasing yield. The relevant research results were published in the Journal of Northwest A&F University (Natural Science Edition) in August 2026 (DOI: 10.13207/j. jnwafu. 2026.08.012)

Research background and significance

Sweet cherries originated in Europe and are one of the fastest-growing fruit trees in China in the past 20 years. In the introduction and promotion of sweet cherries in Xinjiang, the frequent occurrence of abnormal shedding of young fruits during fruit development is particularly prominent, becoming a key factor restricting yield. This physiological barrier occurs in cultivation areas both domestically and internationally. In production, measures such as pruning and pruning, strengthening soil water and fertilizer management, and using fruit preservation agents are mainly adopted to reduce the occurrence of fruit drop, but the effect is minimal and the problem has not been effectively solved. It has also given rise to problems such as tree aging caused by improper use of various fertilizers and fruit preservation agents. Therefore, clarifying the physiological characteristics and laws of fruit drop, analyzing the "source sink" interaction relationship and regulatory mechanism of trees, has become an important research direction for achieving high-quality and high-yield cultivation of sweet cherries. The nutritional competition between plant organs leads to an imbalance in nutrient allocation, which is a key cause of organ shedding. The shedding of sweet cherry fruit is closely related to the competition for nutrients between fruit leaves and the nutritional stress during the young fruit stage. However, there are currently few systematic reports on the distribution characteristics of carbon and nitrogen nutrients between different tissues during the physiological shedding period of the young fruit, the dynamic changes in sucrose metabolism, and its correlation mechanism with fruit drop, especially the regulatory role of key sucrose metabolism enzyme activities.

Core innovation points and research process

This study used the main sweet cherry variety 'Sami Tuo' planted in Xinjiang facilities as the test material, and measured and analyzed five organs including fruit, fruit stem, fruiting branch leaves, new branches and shoots during the fruit development period. The focus was on studying the dynamic content of carbon and nitrogen nutrients in each organ and the changes in key enzyme activity of sucrose metabolism. The aim was to analyze the characteristics of carbon and nitrogen nutrient allocation and sucrose metabolism, and to analyze their correlation with early physiological fruit drop, in order to clarify the nutritional regulation mechanism of normal development of sweet cherry fruit, and provide theoretical support for optimizing cultivation management techniques, reducing physiological fruit drop, and increasing yield.

The research results (Figure 1-3) indicate that during the fruit development period of sweet cherries, the longitudinal and transverse diameter growth of the fruit changes in an "S" shape, with a rapid growth period of 29-36 days after the peak flowering period. The rapid growth period of fruit stem length and thickness occurs before 22 days and 29 days after the peak flowering period, respectively; The thickness of new shoots continues to increase over time, and the rapid growth period of length is 22-36 days after the peak flowering period, with a slower growth rate in the later stage. The total nitrogen content of all organs showed an overall decreasing trend; The total carbon content showed a trend of first increasing and then decreasing in fruits, fruit stalks, and fruiting branches and leaves, while the content in new shoots and leaves showed an upward trend. The sucrose content in the fruit increases rapidly before 29 days after the peak flowering period and then stabilizes. In the later stage of development, the sucrose content in the fruit increases rapidly again; The trend of changes in sucrose content in other organs is not significant, fluctuating slightly between 5-35 mg/g. The activity of sucrose synthase decomposition direction (SS-I), sucrose phosphate synthase (SPS), and neutral invertase (NI) in various organs showed little difference during the young fruit stage, but their activity rapidly increased in the fruit after the hard core stage. The overall trend of changes in the synthesis direction of sucrose synthase (SS-II) and the activity of soluble acid invertase (S-AI) in various organs is similar, with a significant upward and downward trend before 36 days after the peak flowering period. The physiological fruit drop period mainly occurs 15-36 days after the peak flowering period, and the entire physiological fruit drop process lasts for 22 days, reaching its peak at 29 days after the peak flowering period. The results of principal component analysis and path analysis indicate that the sucrose content in the fruit directly regulates the occurrence of fruit drop, while related metabolic enzymes indirectly affect the occurrence of fruit drop by regulating sucrose content.

Application value and future prospects

Fruit sucrose is the key to regulating fruit drop, and the carbon and nitrogen nutrition and sucrose metabolism enzymes in the fruit and fruit stalk indirectly affect fruit drop by affecting the supply of fruit sucrose. In summary, the early fruit drop of sweet cherries is related to the dynamic competition of sucrose metabolism between new shoots and young fruits, and regulating the carbon nitrogen ratio and key enzymes in sucrose metabolism can reduce physiological fruit drop. Therefore, in the production of sweet cherries, attention should be paid to timely adjusting the carbon nitrogen ratio during fertilization, improving the activity of sucrose metabolism enzymes, in order to reduce physiological fruit drop and increase yield by affecting sucrose supply.

Quoting this article

Zhang Jinqiang, Li Pengcheng, Wang Huanhuan, etc Correlation analysis of early physiological fruit drop, carbon and nitrogen nutrition, and sucrose metabolism in sweet cherries [J]. Journal of Northwest A&F University (Natural Science Edition), 2026,54 (08): 111-120. DOI: 10.13207/j.jnwafu.2026.08.012

Title:

Correlation analysis of early physiological fruit drop and carbon-nitrogen nutrition and sucrose metabolism in sweet cherry （Prunus avium L.）

Journal Name: Journal of Northwest A&F University （Natural Science Edition）

DOI: 10.13207/j.jnwafu.2026.08.012

URL: https://scholarcast.cast.org.cn/top-news/2089901411535572992