Differential regulation of enzyme activities and physio-anatomical aspects of calcium nutrition in grapevine

Understanding calcium functionality by examining growth characteristics and structural aspects in calcium-deficient grapevine

“…This pattern contradicts other species such as the trifoliate rootstock seedlings ( Poncirus trifoliate L.), wherein Ca deficiency significantly decreased the fresh and dry weight of root, stem, and leaves 30 . The chlorosis is due to the disintegration of chloroplasts by starch accumulation 10 , 31 , 32 , given that Ca 2+ is needed for exporting photosynthates out of leaves to other growing organs 9 . On the other hand, the reduced leaf area is associated with the altered morphology of mesophyll (palisade parenchyma) cells leading to reduced photosynthesis in the Ca 2+ -deficient vines 10 .…”

“…To gain a realistic understanding of how Ca 2+ influences the growth and structure of plants, including their productivity 2 , 7 , we need to reveal how Ca 2+ transport and function are integrated from the whole plant to the subcellular level in different species 8 . Progress in this endeavor requires in-depth characterization and fundamental understanding of the symptomatology of organs in different plants at the whole plant and cellular levels by conducting starvation studies under controlled conditions 1 , 9 , 10 . Unlike other nutrients 11 , 12 , the links between Ca 2+ deficiency and its symptomatology in different organs, including the complex interaction among other nutrients in its absence in various crops, are paradoxical, hence the limited understanding of its functionality 5 .…”

“… 5 . Our recent paper 10 has covered some of this information by examining the physiology and carbohydrate metabolism (enzymes involved in photosynthesis and sugar metabolism) in Ca 2+ -sufficient and Ca 2+ -deficient grapevines. This study aims to comprehend the Ca 2+ deficiency symptomatology related to growth, nutrient distribution, and morpho-anatomical and ultrastructural alterations of root and shoot systems.…”

Sucrose Metabolism and Transport in Grapevines, with Emphasis on Berries and Leaves, and Insights Gained from a Cross-Species Comparison

“…However, the proportion of sucrose contained in the vacuole is dependent on a number of factors, and environmental conditions that limit sink demand can lead to a substantial increase [31]. Similarly, in grape leaves, sucrose content can increase during the day under certain conditions [32], and it is possible that the sucrose in excess of that required for export is stored in the vacuole [33].…”

Data_Sheet_1.doc

“…Following long-distance delivery, sucrose is unloaded from the phloem SE to the storage parenchyma cells through the symplastic-unloading pathway or the apoplastic-unloading pathway. In the latter case, sucrose is taken up into the parenchyma apoplasm by the members of the SUT1/SUC2 transporter family and is then hydrolyzed by cell-wall invertase (CWINV) or sucrose synthase into hexoses (Chen et al, 2017;Wan et al, 2018;Duan et al, 2020). Hexoses enter the parenchyma cells via specific monosaccharide transporters at the plasma membrane or the tonoplast level (Corelli Grappadelli et al, 2019).…”