Leaf turgor pressure in maize plants under water stress

Abstract

Maize grown is affected by water stress reducing photosynthetic rate and availability of water in its tissues, decreasing plant yield. Monitoring plant water potential is an important indicator of the degree of water stress. With the new magnetic probe for determining leaf turgidity, it is possible to evaluate the water status of the plant and, in some cases, to indicate the optimal relative tolerance to water stress. The union of new and old approaches gives us a better knowledge of water relations in plats. Therefore, the aim of this study was to understand the behavior of maize plants subjected to water stress, using novel and conventional approaches. Maize plants were grown in pots in a greenhouse for 45 days. After this period, plants were subjected to water stress, where turgor measurements expressed by the variable Pp (patch pressure) were monitored. In addition, the leaf water potential, stomatal conductance, CO 2 assimilation, transpiration rate, and variable growth (height, leaf area and dry weight) had been monitored for 30 days. Two treatments were conducted, one in which the plant was irrigated and the other one in which irrigation was fully suspended for a period of time and monitored the water status. As the days passed, the plants showed the first visual signs of stress like leaf rolling. During this period, we observed fluctuating Pp values throughout the day, but with a recovery of turgor at night. There were significant differences between treatments for stomatal conductance, water potential, photosynthesis, and Pp, mainly before irrigation. After each irrigation, there has been a rapid recovery in all parameters. There was five periods of stress and it is possible to see a pattern of decreasing and increasing the Pp as the advance of stress, mainly in the last two. Maize plants had a big resilience in water stress conditions, due to mechanisms of water loss mitigation, like leaf rolling and possibly osmotic adjustment. Thus, it was concluded that Pp introduced a new approach to study plants subjected to water stress and it is a complement to other variables as CO 2 assimilation rate, stomatal conductance, transpiration rate, and leaf water potential.

Relative leaf expansion rate and other leaf-related indicators for detection of drought stress in chili pepper (Capsicum annuum L.).

“…Leaf sensitivity to water shortage condition was due to its direct association and interaction with the surrounding environment, i.e., light capture, gas exchange, and thermoregulation (Chitwood and Sinha, 2016). Leaf played important role in transpiration process for maintaining cell turgidity, temperature, and controlling mechanistic movements, including opening and closing of stomata and leaf folding as initial symptoms of stress (Riboldi et al, 2016) Response of sensitive leaf to soil drying condition is expressed in deceleration of its expansion rate. This can be a very useful indicator in evaluating impact of drought stress on plant growth and development.…”

Water Status Evaluation of Maize Cultivars Using Aerial Images

“…The gas exchange variables were not affected by the cultivars, nor by the interaction between water regimes and cultivars (Table 3). However, physiological changes in stomatal conductance, net CO 2 assimilation rate, and transpiration in maize plants subjected to full and deficit irrigation were detected in other studies (BIANCHI et al, 2007;RIBOLDI, OLIVEIRA;ANGELOCCI, 2016;SABAGH;BARUTÇULAR;ISLAM, 2017). ); E = transpiration rate (mmol H 2 O m -2 s -1 ); CV = coefficient of variation; *** = significant by the F test at ≤ 0.001; ns = not significant.…”

“…Higher stomatal conductance values are found when the solar radiation is high and the leaf water potential has not yet reached the minimum values to induce stomatal closure. Plants tend to decrease stomatal conductance under water deficit conditions as a strategy to avoid water loss to the atmosphere (RIBOLDI, OLIVEIRA;ANGELOCCI, 2016;SANTOS et al, 2018).…”

The effect of drought stress on physiological responses of maize plants originating from seeds of different ages

“…Pri delovanju stresa suše u biljnim tkivima opada sadržaj vode, koji nastaje zbog smanjenog usvajanja i/ili povećanog odavanja vode. Tako kod biljaka dolazi do narušavanja vodnog potencijala, pri čemu njegove negativnije vrednosti ukazuju na prisustvo većeg stepena stresa suše, koji kod ćelija zatvaračica dovodi do opadanja turgora i zatvaranja stoma (Chaves et al, 2009;Riboldi et al, 2016;Moles et al, 2018).…”

“…3A). U suši opada vrednost vodnog potencijala, što dovodi do inhibicije porasta nadzemnog dela biljke (Achard et al, 2006;Zgallaï et al, 2006), opadanja turgora i zatvaranja stoma (Chaves et al, 2009;Moles et al, 2018) i smanjenja intenziteta fotosinteze (Riboldi et al, 2016). Ukupni vodni potencijal se posmatra kao hidraulički signal koji utiče na zatvaranje stoma.…”