Ecophysiological performance of a threatened shrub under restored and natural conditions in a harsh tropical mountaintop environment

Abstract

Ecophysiological responses of plants are useful for monitoring the success of ecological restoration projects that target species conservation. In this study we evaluated the ecophysiological traits of individuals of Chamaecrista semaphora from a natural population and from a site under restoration. Water potential and chlorophyll a fluorescence parameters were measured both in adult and young plants of the two populations. No difference in water potential was found between sites, but individuals in the restored site had higher water potential at predawn. Adults in the natural site presented lower daily values of potential quantum yield, indicating the occurrence of photoinhibition. Individuals in the restored site also presented higher maximum relative electron transport rate (ETR MAX ). No difference was found in leaf carbon isotope discrimination values ( 13 C) between plants growing in restored and natural sites, suggesting similar water use efficiency. These results indicate that C. semaphora individuals in the restored site had similar or better photosynthetic and water economy performances than individuals at the natural site. Methodologies traditionally employed to assess stress response of plants, such as chlorophyll a fluorescence and procedures used to evaluate the efficiency of water use, allowed us to verify the success of restoration procedures using an endangered species.

Photosynthetic heat tolerance in plants with different foliar water ‐uptake strategies

“…The species with high C max are more efficient photosynthetically than the species that absorb water rapidly (high k ) due to the high water potential induced by fog (Boanares et al, 2019). Moreover, late afternoon recovery of F v /F m values and absence of photoinhibition are indicative of the effectiveness of mechanisms that dissipate the excess light in these plants (Castro et al, 2016). The species with high C max ( E. erythropappus , M. corallina , T. laniflora , and P. heteromallum ), whose leaf anatomical traits facilitate water storage also protect the photosynthetic apparatus, since a high amount of water plays a key role in photosynthesis.…”

“…Such a mechanism provides energy imbalance between light absorption and utilization, which minimizes the possibility of photooxidative damage (Demmig-Adams and Adams, 2006). The damage to the PSII under excessive light has been reported for some species in campo rupestre (Castro et al, 2016) and may be minimized by fog water input.…”

Responses of Neotropical Savannah Plant Species to Abiotic Stresses: A Structural and Functional Overview

“…The seasonality of water availability can also result in dynamic photoinhibition in woody plants [62], but not in herbaceous species [63][64][65]. A reduction of stomatal conductance and of net CO 2 assimilation has also been reported in Barbacenia Purpurea (Velloziaceae) submitted to water stress, but recovery was detected hours after rehydration [50].…”