³¹P-Nuclear Magnetic Resonance Determination of Phosphate Compartmentation in Leaves of Reproductive Soybeans (Glycine max L.) as Affected by Phosphate Nutrition

Abstract

Most leaf phosphorus is remobilized to the seed during reproductive development in soybean. We determined, using (31)P-NMR, the effect phosphorus remobilization has on vacuolar inorganic phosphate pool size in soybean (Glycine max [L.] Merr.) leaves with respect to phosphorus nutrition and plant development. Phosphate compartmentation between cytoplasmic and vacuolar pools was observed and followed in intact tissue grown hydroponically, at the R2, R4, and R6 growth stages. As phosphorus in the nutrient solution decreased from 0.45 to 0.05 millimolar, the vacuolar phosphate peak became less prominent relative to cytoplasmic phosphate and hexose monophosphate peaks. At a nutrient phosphate concentration of 0.05 millimolar, the vacuolar phosphate peak was not detectable. At higher levels of nutrient phosphate, as plants progressed from the R2 to the R6 growth stage, the vacuolar phosphate peak was the first to disappear, suggesting that storage phosphate was remobilized to a greater extent than metabolic phosphate. Under suboptimal phosphate nutrition (</= 0.20 millimolar), the hexose monophosphate and cytoplasmic phosphate peaks declined earlier in reproductive development than when phosphate was present in optimal amounts. Under low phosphate concentrations (0.05 millimolar) cytoplasmic phosphate was greatly reduced. Carbon metabolism was coincidently disrupted under low phosphate nutrition as shown by the appearance of large, prominent starch grains in the leaves. Cytoplasmic phosphate, and leaf carbon metabolism dependent on it, are buffered by vacuolar phosphate until late stages of reproductive growth.

Interactive effects of phosphorus and light availability on early growth of maritime pine seedlings

“…In our experiment, growth independent P consumption was observed in the P free-access treatments. This can be attributed to the accumulation of inorganic phosphorus (Pi) in the vacuole [32,46] and to a higher concentration of P incorporated in organic compounds in the cell as polyphosphate or phytate [13]. This ability may be ecologically important in enabling plants to face seasonal variations in phosphorus availability observed in the field [10].…”

Effect of Phosphorus Application and Varieties on Grain Yield and Yield Components of Common Bean (Phaseolus vulgaris L.)

“…This could be because of increased cytokinins synthesis (Horgan and Wareing, 1980) and supply of photosynthates (Marschner, 2012) for flower formation. Perhaps, P deficiency has been related to the reduction in foliar expansion (Fredeen et al, 1989), decrease in the number of leaves (Lynch et al, 1991) and loss in photosynthetic efficiency (Lauer et al, 1989).…”

Metabolic Adaptations of Plant Respiration to Nutritional Phosphate Deprivation

“…P-NMR studies have revealed that plant cells selectively distribute Pi between cytoplasmic ("metabolic") and vacuolar ("storage") pools, with cytoplasmic Pi being maintained essentially constant at the expense of large fluctuations in vacuolar Pi (Lauer et al, 1989). With prolonged Pi-deprivation, however, vacuolar Pi stores become exhausted, and this is followed by considerable reductions in cytoplasmic Pi (Lauer et al, 1989).…”

“…At the metabolic level, much attention has been devoted to the effect of Pi status on the secretion of acid phosphatases, Pi uptake rates, and other mechanisms that may serve to increase the availability of Pi to Pi-deprived cells (Goldstein et al, 1989;Lefebvre et al, 1990;Duff et al, 1991aDuff et al, , 1991b. The effects of Pi nutrition on the rates of photosynthesis and photosynthate partitioning in leaves have also been well documented (Thorsteinsson and Tillberg, 1987;Lauer et al, 1989;Fredeen et al, 1990). By contrast, investigations of the metabolic adaptations of plant respiratory pathways to Pi deficiency have been limited.…”