Gas exchanges and growth of soybean cultivars submitted to water deficiency

Abstract

<jats:p>ABSTRACT A low availability of water in the soil may alter morphological traits and physiological processes in soybean, limiting its development, mainly at late sowings. This study aimed to evaluate the leaf gas exchanges and dry matter accumulation in soybean cultivars under low water availability at late sowing. An Oxisol with a very clayey texture was employed. A completely randomized design, in a 5 × 3 factorial scheme, with four replications, was used. The treatments were five water tensions (10 kPa, 15 kPa, 25 kPa, 40 kPa and 60 kPa) combined with three soybean cultivars (BRS Favorita, BRSMG 820 and BRSMG 850). The response variables were measured at 55 days after the emergence. The values for stomatal conductance, transpiration, photosynthesis rate, intercellular CO2 concentration and instantaneous carboxylation efficiency were significantly reduced (p &lt; 0.05) with the increase of the water tension in the soil. The gas exchanges in the soybean plants were also reduced with the increase of the water tension in the soil, being the most critical ones observed from 25 kPa. BRSMG 850 showed the best performance for production of root dry matter in this water tension in the soil.</jats:p>

Remote Detection of Water and Nutritional Status of Soybeans Using Uav-Based Images

“…Stomatal conductance (gs) in treatments under full irrigation (690.8 mmol H2O m -2 s -1 ) was higher than that of treatments under deficient irrigation (487.6 mmol H2O m -2 s -1 ) (Figure 3). Machado Junior et al (2017) and Silva et al (2020) also observed gs reductions in soybeans under soil water restriction. Stomatal conductance was the highest when solar radiation was high and leaf water potential had not yet reached minimum values to induce stomatal closure.…”

“…Fine Sand Silt Clay Textural Classification ---------------------------g kg -1 ---------------------------- Fertilization was managed based on the soil chemical analysis. Nitrogen (urea), phosphorus (simple superphosphate), and potassium (potassium chloride) were applied to the soil, while micronutrients were sprayed on leaves (Silva, 2021). The dose of 1,000 kg N ha -1 was selected to meet soybean N demands throughout the crop season so that both cultivars could express their maximum yield potentials (6 Mg ha -1 expected yield).…”

Photosynthetic adjustments and proline concentration are probably linked to stress memory in soybean exposed to recurrent drought

“…The accumulation of total dry mass is important for soybean productivity; however, it is affected by water stress. The decrease in plant biomass under severe stress is related to the effects on stomatal closure and decreased net photosynthesis (Silva et al, 2020). However, the nonsignificant difference in grain dry mass between WW and WS-R1+R5 demonstrates memory to minimize the effect of stress, maintaining the production of photoassimilates, partitioning them, and allocating them more efficiently, resulting in the maintenance of grain production.…”

Enhancing Sustainability in Potato Crop Production: Mitigating Greenhouse Gas Emissions and Nitrate Accumulation in Potato Tubers through Optimized Nitrogen Fertilization

“…The internal CO 2 concentration (Ci; µmol CO 2 m −2 s −1 ), transpiration rate (E; mmol H 2 O m −2 s −1 ), stomatal conductance (gs; mmol H 2 O m −2 s −1 ), and net photosynthetic rate (A; µmol m −2 s −1 CO 2 ) were evaluated using a portable gas exchange device (LC-PRO+, ADC Bioscientific Ltd. Hoddesdon, UK) under a photosynthetically active radiation (PAR) of 1200 µmol m −2 s −1 . Based on these data, water use efficiency (WUE; µmol CO 2 mmol −1 H 2 O) was calculated through A/E [21].…”