Phosphorus as a mitigator of the effects of water stress on the growth and photosynthetic capacity of tropical C4 grasses

Abstract

Water deficiency during the dry seasons influences the relationship between water and gas exchange in tropical grasses, reducing their productive potential. In addition, the phosphorus (P) deficiency Brazilian soils adds to the set of factors limiting crop production. In this context, the objective of this study was to evaluate the responses of different tropical forage species to phosphorus supplementation as mitigating the damage caused by water stress. Seeds of Urochloa brizantha cv. MG-4, Urochloa decumbens cv. Basilisk, Panicum maximum cv. Áries, Panicum maximum cv. Tanzânia and Paspalum atratum cv. Pojuca were germinated in pots containing 10 liters of red-yellow Acrisol type soil. Experiments were conducted by combining levels of phosphorus, 8,0 and 100,0 mg of P dm-3, with two irrigation regimes, 100 and 40% replacement of transpired water. The biometric parameters, photosynthetic capacity, leaf water potential and soil chemical characteristics were evaluated, and the data was submitted to analysis of variance (ANOVA, p < 0.05), and subsequently the means were compared using a Tukey test (p < 0.05). The results showed for tropical grasses grown under water stress, there is a clear mitigating effect of phosphorus supplementation, especially on the maintenance of biomass growth.

Gas exchange and millet phytomass under organic fertilization and graywater irrigation

“…At 30 and 45 DAT, A did not differ between treatments with and without fertilizer; however, a difference did occur at 60 DAT when A was higher in the treatment without fertilizer (Table 2). The A was higher when millet was in a balanced nutritional management, contributing to mitigating water stress and providing rapid initial growth (Kuwahara et al, 2016). By obtaining higher gas exchanges at the beginning of growth, plants that received fertilization completed their cycle in a shorter period than plants without fertilization, justifying the drop in gas exchanges they exhibited at 60 DAT.…”

Influence of water scarcity on macronutrients contents in young leaves of wine grape cultivars

“…It is the building block of important macromolecules such as nucleic acids, phospholipids, adenosine triphosphate (ATP). It also takes part in many biochemical reactions and metabolic cycles (Kuwahara et al, 2016). Like total N, P deficiency is often associated with the restriction of plant growth.…”

Impact of phosphorus and luminosity on the propagation, photochemical reactions and quality of Lippia alba (Mill.) N.E.Br. seedlings

“…P plays an important role in plant biomass allocation and is a structural component of nucleic acids, phospholipids and ATP formation, favoring primary metabolism reactions and constituting ~ 0.2% of plant mass (Kuwahara et al, 2016). For seedling production in Dalbergia nigra Benth., it was found that the addition of 500 mg kg -1 of P favored an increase in biomass (Carlos et al, 2018), similar to the L. alba seedlings in this study (Tab.…”

“…Generally, P-deficient plants may suffer damage in diffusive and non-diffusive processes of photosynthetic metabolic pathways through a reduction in consumption and regeneration of Rubisco and production of ATP and NADPH (Andrade et al, 2018), which may cause instability in the photochemical process in PS II. Thus, phosphate fertilization is an important agronomic practice since it may assist in photochemical stability (Carstensen et al, 2018) and biomass increases in plants (Kuwahara et al, 2016).…”