ABSTRACT
BACKGROUND: Sweet cherry trees (Prunus avium L.) of the cultivar Grace Star were pruned either in dormancy or in summer. The response was studied by analyzing the sugar content in different organs (flower bud, leaf, and fruit) at three sections of the canopy (inner, outer, and upper) using high-performance liquid chromatography. The effect of summer pruning was evaluated by measuring photosynthetic photon flux density (PPFD) and leaf chlorophyll content (SPAD). RESULTS: In this study, the timing of pruning had a significant effect on sugar content in flower buds, leaves, and fruit. Trees pruned in summer had higher glucose, fructose, sorbitol, and sucrose content in flower buds, higher glucose and fructose contents in leaves, and lower fructose, sorbitol, and total sugar content in fruit than in trees pruned at dormancy. Higher average PPFD and lower SPAD values were measured in the inner canopy of trees pruned in summer. All measured parameters were influenced by position in the canopy. The lowest fructose and sorbitol contents in the flower bud, the lowest content of glucose, fructose, sorbitol, total sugars and the highest SPAD values in the leaf, while less dark and lighter fruit were measured in the inner part of the canopy. CONCLUSION: Summer pruning affects sugar distribution in the tree by altering irradiation conditions within the canopy. Our results suggest that summer pruning is an effective technological measure to improve sugar content in the buds. A strong, well nourished flower bud is a good indication of high fruit production next season. © 2021 Society of Chemical Industry.
Subject(s)
Crop Production/methods , Fruit/chemistry , Prunus avium/growth & development , Sugars/analysis , Chlorophyll/analysis , Chlorophyll/metabolism , Flowers/chemistry , Flowers/metabolism , Fruit/growth & development , Fruit/metabolism , Photosynthesis , Plant Leaves/chemistry , Plant Leaves/metabolism , Prunus avium/chemistry , Prunus avium/metabolism , Seasons , Sugars/metabolismABSTRACT
The influence of a water supply on the content of phytochemicals (sugars, organic acids, hydroxycinnamic acids, flavonols, flavanols and anthocyanins) in the bud, leaf and fruit of sweet cherry (Prunus avium L.) was studied in two growing seasons. In addition, the shoot length, yield efficiency and fruit weight were determined. The trees of the cultivar 'Regina' on Weiroot 72 or Gisela 5 rootstocks were either irrigated or non-irrigated. Irrigated trees received, in addition to rainfall, an amount of water equal to 100% of evapotranspiration, while non-irrigated trees received only rainwater (40% less). An analysis of phytochemicals was performed using high-performance liquid chromatography combined with electrospray ionization mass spectrometry. Irrigated trees had a higher content of total sugars in leaf and bud, higher content of total organic acids in the fruit, and lower content of total hydroxycinnamic acids, total flavonols and flavanols in the leaf and fruit. Irrigated trees also had higher shoot length, fruit weight and lower yield efficiency. The content of phytochemicals in bud and leaf was not affected by rootstock, but the fruit phytochemical composition, shoot length and yield efficiency were. The content of phytochemicals in the bud and leaf was influenced by the presence or absence of fruits. Our results show that irrigation, rootstock and the presence of fruits had an influence on the composition of phytochemicals in sweet cherry.
