This study investigated the effects of recurrent water deficit on drought tolerance traits in black pepper (Piper nigrum L.) 'Bragantina'. Plants were subjected to three cycles of water deficit followed by recovery periods. Water deficit reduced stomatal conductance, photosynthesis, transpiration, and water potential while increasing water-use efficiency. In addition, intercellular CO2 concentration, leaf temperature, root starch, and adaptive morphological characteristics in leaves and roots increased. Despite these adaptations, plants did not recover vegetative growth after rehydration. The primary tolerance mechanisms observed included increased abaxial epidermis thickness, stomatal density, fine roots, periderm thickness, and starch accumulation in roots. Although gas exchange and leaf water potential were restored, vegetative growth did not fully recover. This study highlights the response of black pepper to recurrent water stress and the underlying mechanisms of its drought tolerance.

• Klíčová slova
• anatomy, black pepper, drought cycles, gas exchange, vegetative growth,
• Publikační typ
• časopisecké články MeSH

This study investigates how cocoa rootstocks respond to flooding and post-flooding conditions, offering insights for cocoa plantation sustainability in flood-prone areas due to climate change. We studied Theobroma cacao L. rootstocks for 60 d of flooding and 30 d post-flooding, grafting PS-1319 scions onto five rootstocks (TSH-1188, Cepec-2002, Pará, Esfip-02, SJ-02). Photochemical performance remained stable across rootstocks, while flooding progressively reduced electron transport efficiency. Photochemical damage emerged after 7 d, worsening occurred at 19 d. Although post-flooding efficiency improved, recovery time was insufficient for full restoration. Stem diameter increased less in Esfip-02. TSH-1188 had the highest stem dry mass during flooding and the most root and total dry mass during post-flooding. SJ-02 had the lowest stem dry mass and post-flooding total dry mass. Principal component analysis revealed stem and root development as a key for recovery. SJ-02 and Esfip-02 showed lower flooding tolerance and recovery, while TSH-1188 and Pará exhibited higher resilience.

• Klíčová slova
• cocoa, photosynthesis, plasticity, water stress,
• Publikační typ
• časopisecké články MeSH

Studies that simulate recurrent drought events with subsequent episodes of rehydration better reflect natural conditions and allow visualization of differential acclimatization responses resulting from memory and tolerance mechanisms. Piper aduncum and Piper tuberculatum were grown in a greenhouse and were subjected to three successive cycles of drought and subsequent rehydration. After suspending irrigation, gas exchanges were measured daily with IRGA. When stomatal conductances close to zero were obtained, the plants were rehydrated and kept irrigated. In P. tuberculatum, stomatal conductance was always higher after periods of rehydration compared to the period before the drought, while the transpiration rate was lower only during the drought. The damage to the photosynthetic apparatus was caused by the influence of the interception of the flow of electrons in the transport chain. We came to the conclusion that the dehydrated plants showed an alert signal, which triggered response mechanisms to prevent or deal with the water stress situation.

• Klíčová slova
• Piper aduncum, Piper tuberculatum, anatomical adaptations, compensatory development, water deficit,
• Publikační typ
• časopisecké články MeSH

This study evaluated the side-cleft grafting in native species of the genus Piper (Piper aduncum L., Piper hispidum Sw., and Piper tuberculatum Jacq.) with BRS Kottanadan pepper cultivar as rootstocks (Experiment 1). The top-cleft grafting was evaluated in native species Piper arboreum Aubl., P. aduncum, and P. tuberculatum with Balankotta pepper cultivar as graft using black pepper cv. Bragantina (Experiment 2). Black pepper cv. Bragantina autograft was considered as control. The rootstock P. tuberculatum showed initial incompatibility with the cv. Bragantina, with survival of about 34.8% (side) and 62.5% (top) and total inhibition of graft shooting. The side and top graft on P. aduncum resulted in 84.0 and 47.5% of survival, respectively. The JIP-test parameters indicated better photochemical efficiency in the species grafted using the method of side-cleft grafting. Finally, the initial compatibility was associated with greater survival, shooting, and better energy flow through the electron transport chain.

• Klíčová slova
• JIP test, grafting, pepper, propagation,
• Publikační typ
• časopisecké články MeSH

The study proposes to evaluate the photosynthetic plasticity of Rhizophora mangle L. in four mangrove sites distributed along with the Great Vitória Estuarine System. The variation in organic matter content, which implies the higher essential nutrient availability, contributed to better energy flux performance related to electron transport. Furthermore, salinity damaged the reaction centers (RC), since the site with the highest salinity showed changes in the number and size of active photosynthetic RC and in the specific energy flows per active RC (absorption flux, trapped energy flux, and dissipated energy flux), but the plasticity of the species in response to salt stress was confirmed by the increase of performance index for energy conservation (PITotal), net photosynthetic rate (P N), and the water-use efficiency (WUE). Also, the results showed that the luminous intensity available compromises the functionality of PSII, in turn, it increases WUE. The results indicate the effect of the chlorophyll a content, which provides more substrate for light absorption, on the electron flow and PITotal is related to P N and WUE. The study indicates the ecological plasticity of R. mangle to the conditions of the evaluated area.

• Klíčová slova
• JIP test, gas exchange, photosystems, tropical region,
• Publikační typ
• časopisecké články MeSH