Phosphorus and Carbohydrate Metabolism in Green Bean Plants Subjected to Increasing Phosphorus Concentration in the Nutrient Solution

Abstract

Phosphorus (P) is considered an elementary mineral nutrient for plants. Nevertheless, excessive or deficit supply to the crop may cause negative changes at the physiological level. Plants were cultivated in pots in a growth chamber under increasing P concentration (P1 (0.5 mmol/L (control treatment)), P2 (1 mmol/L); P3 (2 mmol/L); P4 (4 mmol/L); P5 (6 mmol/L), and P6 (8 mmol/L)) in the nutrient solution for 40 days. At the end of the experimental period, biomass, carbohydrates concentration, and enzymatic activities related to the synthesis and degradation of sucrose as well as the different fractions of P in different organs of the plant were assessed. The results obtained in this experiment reveal a decrease in biomass under increasing P supply. Fructose, glucose, sucrose, and starch concentrations were higher in the shoots compared to the roots. There were different trends in the roots and shoots in enzymatic activities related to sucrose. The increase in P dose increased the concentration of the different forms assessed for P in all the organs studied. Seed phytate concentration surpassed the threshold established by the Food and Agriculture Organization (FAO) for green bean plants grown under P4, P5, and P6 treatments. Considering the results obtained, we suggest fertigation with a concentration of 2 mmol/L to obtain a higher productivity without excess of phytate in seeds.

Cultivar-Dependent Responses in Plant Growth, Leaf Physiology, Phosphorus Use Efficiency, and Tuber Quality of Potatoes Under Limited Phosphorus Availability Conditions

“…This resulted in a huge increase of these reducing sugars in response to increasing P applications, especially for Agria, Lilly, and Milva ( Figure 5F ). The conversion of sucrose to reducing sugars is regulated by enzymes such as invertase, sucrose phosphate synthase, and fructose 1,6-bisphosphatase, which are enhanced under sufficient P supply conditions (García-Caparrós et al, 2021 ). The less or no reduction of sucrose in the leaves under P-deficient conditions could also be caused by either limited sugar transport or the sugar conservation response of plants.…”

Zinc sulphate or zinc nanoparticle applications to leaves of green beans

“…In general, a gradual increase in the concentration of this soluble sugar was observed in this research. This could be due to the simultaneous need to accumulate and translocate sucrose as a source of carbon and energy to the shoots and pods, as part of the overall growth and development (García-Caparrós et al, 2021).…”

“…The small differences found can be associated with the solubility characteristics of ZnSO 4 , which when applied to leaves can drop rapidly; therefore, the bioavailability of Zn 2+ ions over a prolonged period is uncertain (Doolette et al, 2018). In addition to its physical properties (size, structure and particle shape), previous studies with foliar applications of ZnO NPs varying between 1,000 mg ⋅ L −1 and 2,500 mg ⋅ L −1 on Brassica nigra and Capsicum chinense indicate a significant effect on FT and TFl concentrations (Zafar et al 2016;García-López et al, 2019). On the other hand, Abbasifar et al, (2020) when applying 1,000 mg ⋅ L −1 , 2,000 mg ⋅ L −1 or 4,000 mg ⋅ L −1 report a significant increase in the concentration of flavonoids in basil leaves (Ocimum basilicum L.).…”

“…It is known that under optimal conditions, Zn 2+ plays an important role in the synthesis and activation of superoxide dismutase (SOD), the main enzyme associated with the removal of reactive oxygen species (ROS) (Korkmaz et al 2018). This behaviour changes radically when the concentration of this micronutrient is at phytotoxic levels, causing oxidative stress (García-López et al, 2019). In this sense, the response to foliar Zn 2+ application is a function of the species, nutrient status, phenological stage, dose supplied and number of applications (Shang et al, 2019;Abbasifar et al, 2020).…”

“…EDTA-Zn) (Pedruzzi et al, 2020). However, their foliar uptake efficiency is relatively low because Zn 2+ absorption by the leaf depends on the chemical nature of the source (García-López et al, 2019).…”