Changes in leaf water potential and photosynthesis of Bauhinia forficata Link under water deficit and after rehydration

Abstract

-(Changes in leaf water potential and photosynthesis of Bauhinia forficata Link under water deficit and after rehydration). To evaluate the influence of different intensities of water deficit and rehydration on water relations and gas exchanges of Bauhinia forficata Link, plants were grown in a greenhouse for three months under the following water regimes: daily watered (control) and watered every 7 (7D) and 15 days (15D) returning to daily watering on 7D and 15D treatments at 75 days of the experiment. Aiming to evaluate short-term responses to re-hydration, plants of 7D and 15D treatments were re-watered 2 days before measurements and sampling was carried out at the 45 th day of experiment. At fortnightly intervals (15, 30, 45, 60, 75, and 90 days) soil moisture (Usoil), leaf water potential (Ψwf), photosynthesis in response to photosynthetically active radiation (A × PPFD) to obtain the maximum net photosynthesis (Amax), and light saturation point (PARsat) were evaluated. The water deficit has affected water relations and photosynthesis with the lowest values observed in the treatments Usoil 7D, and 15D respectively, coinciding with the lowest Ψwf and Amax. Changes in PARsat in response to water deficit were observed showing mean values of 665, 275 and 254 µmol photons m -2 s -1 in control, 7D and 15D respectively. The return of daily watering after 75 days of experiment, promoted the recovery of Amax (7.8 and 9.6 µmol CO 2 m -2 s -1 ) and PARsat (588 and 643 µmol photons m -2 s -1 ) in 7D and 15D respectively with values higher than control plants (4.7 µmol CO 2 m -2 s -1 and 631 µmol photons m -2 s -1 ), suggesting a strong dependence of photosynthesis of Bauhinia forficata to the soil water availability. Key words: Brazilian Orchid-tree, drought tolerance, plasticity RESUMO -(Alterações no potencial hídrico foliar e fotossíntese de Bauhinia forficata Link sob déficit hídrico e após reidratação). Para avaliar a influência de déficits hídricos de diferentes intensidades e da reidratação nas relações hídricas e trocas gasosas, plantas de Bauhinia forficata Link foram cultivadas em casa de vegetação durante três meses e submetidas aos regimes de regas diárias (controle) e regas a cada 7 (7D) e 15 dias (15D) retornando as regas diárias nos regimes 7D e 15D aos 75 dias de experimento. Com o objetivo de avaliar respostas de curto prazo à re-hidratação, plantas dos tratamentos 7D e 15D foram re-irrigadas 2 dias antes das medidas realizadas no 45º de experimento. Em intervalos quinzenais (15, 30, 45, 60, 75 e 90 dias) foram avaliadas a umidade do solo (Usolo), potencial hídrico foliar (Ψwf), a fotossíntese em resposta a radiação fotossinteticamente ativa (A × PPFD) para obtenção da fotossíntese máxima (Amax) e da radiação fotossinteticamente ativa na saturação (PARsat). O déficit hídrico afetou as relações hídricas e fotossíntese, sendo que os menores valores de Usolo observados nos tratamentos 7D e 15D respectivamente, coincidiram com os menores Ψwf e Amax. Alterações nos PARsat em resposta ao déficit hí...

Drought-stress tolerance in three semi-arid species used to recover logged areas

“…Photosynthesis was found to rapidly recover in all the three studied species, although B. monandra showed to recover most rapidly. Similar to our results, after water deficiency, another species of the same genus, Bauhinia forficata Link rapidly recover photosynthetic rates when soil-water availability was reestablished (Sanches and Silva 2013). According to Sanches and Silva, photosynthetic activity is strongly dependent on the soil-water availability, as was also observed in our work.…”

Tracing the Responses of Pedunculate Oak (Quercus Robur L.) Trees to Drought Stress by Analyzing the Antioxidant System

“…Considering available data about soil properties at the forest reserve Stara Vratična (locality 4), it might be assumed that typical and haplic gleysol is characterized as the soil that is strongly affected by soil water (Kostić et al, 2021). Thus, although in forest reserve locality the lowest soil moisture content values in the deeper soil layers (30 and 50 cm) were observed, without the drop of pre-dawn water potential (PWP), the obtained values for all examined antioxidant tests (except ABTS) could be explained by the fact that before the water deficit has been established, roots have to sense the dry soil and transmit this information to shoot, which creates an integrated response of the plant allowing its survival until the water availability increases (Sanches and Silva, 2013).…”

NMR-Based Metabolomics Reveals Effects of Water Stress in the Primary and Specialized Metabolisms of Bauhinia ungulata L. (Fabaceae)

“…Irrigation was controlled by drip during a total period of 90 days. The experimental groups were divided as follows: daily watered (control), watered every 7 days (group 7D), and every 15 days (group 15D) [ 14 ].…”

“…Additionally, while some studies have examined the effects of abiotic stress on both metabolisms, they have mainly focused on crop species. For example, Fazani, Sanches and Silva (2013) [ 14 ] evaluated the effects of water deficit on only the primary metabolism of Bauhinia forficata L., a native medicinal plant. On the other hand, Glaubitz et al (2017) [ 15 ] assessed the effect of high temperature on both primary and secondary metabolism in rice plants ( Oryza sativa L. (Poaceae)) and observed the involvement of the two metabolisms in an integrated manner as a response.…”