Effects of Spraying Calcium Fertilizer on Photosynthesis, Mineral Content, Sugar–Acid Metabolism and Fruit Quality of Fuji Apples

Abstract

This study was conducted at the Taidong Base of the Shandong Institute of Pomology, Tai’an City, Shandong Province, China, from May to October 2020. The effects of spraying calcium fertilizer on the photosynthetic characteristics, mineral element content, sugar and acid metabolism, and quality of apples were assessed. Fuji Apple Tianhong.2/SH/Malus robusta (M. robusta) was treated with the calcium fertilizers Niucui (Ca ≥ 100 g/L, B: 1–10 g/L) and Naipu 9 (Ca: 90 g/L, Mg: 21 g/L, N: 110 g/L) at the young fruit stage (25 May), the expansion stage (5 July), and the coloring stage (25 September). Water was sprayed as the control application. The results revealed that spraying calcium fertilizer increased the chloroplast pigment content and photosynthetic capacity of the apple leaves. Compared with the control, the net photosynthetic rate of apple leaves sprayed with Niucui increased by 4.3–34.6%, and that of leaves sprayed with Naipu 9 increased by 15.0–57.4%. Spraying calcium fertilizer promoted the accumulation of Ca, Mg, and B mineral elements in leaves and fruits while inhibiting the accumulation of Cu. Spraying calcium fertilizer improved the quality of apple fruit. Compared to the control fruit, the single fruit weight, fruit hardness, soluble solid content, and Vitamin C content of fruit sprayed with Niucui and Naipu 9 increased by 6.5 and 12.1%, 3.6 and 16.1%, 6.3 and 12.0%, and 30.5 and 29.4%, respectively. Spraying calcium fertilizer increased the sugar content and decreased the acid content of the apples. Naipu 9 was more effective at increasing fruit sugar content, especially sucrose and sorbitol, while Niucui was more effective at reducing the acid content, especially malic acid. This was observed because Naipu 9 increased the sugar metabolism enzyme activity, while Niucui increased the acid decomposition-related enzyme activity. In conclusion, according to the nutrition quality and flavor of the fruit, Naipu 9 application was determined to be the best fertilizer for the Fuji apple.

Effect of Pre-Harvest Calcium Treatment on Post-Harvest Fruit Quality of Nanfeng Tangerine

“…Pre-harvest Ca treatment of fruits may effectively delay softening by preserving the tissue structure and cell wall constituents while also reducing the activities of cell-wall-degrading enzymes. Additionally, the foliar application of Ca fertilizer is an environmentally friendly method for preserving freshness, enhancing firmness, increasing Ca content in fruit [18], delaying senescence and ripening [19], reducing physiological and pathological diseases [20], improving fruit quality, and extending storage time [21]. Hence, pre-harvest Ca treatment is a prevalent and efficient agricultural practice [22].…”

“…Hence, nutrients such as TSS, TA, VC, and TSS/TA serve as indicators of fruit aging and storage quality, with the taste of citrus fruits being primarily reliant on the sugar-acid ratio in the pulp [38]. Wang et al [21] discovered that spraying Ca fertilizer during the young fruit, expansion, and coloring stages enhanced the individual fruit weight, firmness, TSS, and VC content in apples. Sabir et al [39] demonstrated that post-harvest treatment of blackberries with 2% CaCl 2 extended their storage life and delayed changes in TA, TSS, VC, and total phenol content.…”

Synergistic effect of seaweed extract and boric acid and/or calcium chloride on productivity and physico-chemical properties of Valencia orange

“…Ca and B also play a role in photosynthetic efficiency, boosting produced minerals in the leaves and growing fruit ( Bhatt et al, 2012 ; Sheikh et al, 2021 ). Exogenous Ca application improves photosynthesis, the accumulation of mineral elements in leaves, the growth rates of plant leaves, and significantly improves the fruit quality of some fruit trees ( Wang et al, 2022 ). Calcium and boron treatments might improve sugar components through calcium and boron’s active involvement in the photosynthesis of metabolites and rapid translocation of sugars, improving sugar metabolism and translocation of assimilates from other parts of the plants to developing fruits ( Singh et al, 2018 ).…”

“…Calcium, a macronutrient, is an essential element for plant growth and development and is considered an important intracellular messenger, mediating responses to hormones, stress signals, and a variety of developmental processes. Calcium also plays an important role in improving fruit set, retention, development, yield, and quality ( Mahmoudi, Akhlaghi & Forootan, 2009 ; Hepler & Winship, 2010 ; Chakerolhosseini et al, 2016 ; Eticha et al, 2017 ; Wang et al, 2022 ), and in sustaining fruit firmness and the proliferation of vitamin C. Calcium defends membrane disorganization, protects the apparent free space of tissue generally related to senescence, and sustains the protein manufacturing capability of cells ( Hussain et al, 2012 ; Kazemi, 2014 ). Calcium is extremely important in maintaining the strength of stems and stalks of plants, regulating the absorption of nutrients across plasma cell membranes, and in cell elongation and division, the structure and permeability of cell membranes, and nitrogen metabolism.…”

“…Calcium is extremely important in maintaining the strength of stems and stalks of plants, regulating the absorption of nutrients across plasma cell membranes, and in cell elongation and division, the structure and permeability of cell membranes, and nitrogen metabolism. Calcium stimulates the development of lignin and cellulose and the translocation and formation of carbohydrates ( Aguayo, Escalona & Artés, 2008 ; Wang et al, 2022 ; Yang et al, 2023 ), so it is a significant factor in inflorescence and flower formation ( White & Broadly, 2003 ). Calcium also increases the mechanical power of the cell wall because the main component of the cell wall in plants is calcium pectate, which plays a significant role in the establishment of the pedicel attachment to proximal fruit, thus reducing fruit drop ( Guardiola & Garcia, 2000 ; El-Shafey, Abd El-Rahman & El-Azaze, 2002 ; Liu et al, 2019 ; Zaman et al, 2020 ).…”