scholarly journals Physiological responses of Triplaris gardneriana Wedd. seedlings (Polygonaceae) under intermittent drought

2022 ◽  
Vol 17 (12) ◽  
Author(s):  
Elizamar Ciríaco Da Silva ◽  
José Roberto Vieira Aragão ◽  
Iére Barros Bispo ◽  
Islayne da Cruz Menezes ◽  
Hugo Henrique Costa Do Nascimento

Triplaris gardneriana Wedd is a deciduous riparian tree occurring in areas with different climatic conditions in Brazil, from the rainforest to the tropical dry forest. An increase in global temperature and drought events can change the growth pattern and establishment of the species. To evaluate the effects of intermittent drought on the growth of T. gardneriana seedlings, an experiment was performed using seedlings with one month old subjected to three water treatments (daily irrigation as control, and intermittent drought through cycles of water suppression of seven (S7) and 14 days-intervals (S14) between watering. Growth, biomass production and partitioning, relative water content (RWC), the accumulation of organic solutes, protoplasmic integrity and phenotypic plasticity index (PPI) were evaluated for a better understanding about its drought tolerance level. Intermittent drought severely affected plants growth in S14 plants, showing lower plant height, number of leaves, leaf area, and dry biomass. RWC was reduced, while carbohydrates and proline contents increased in response to drought stress. Protoplasmic damage increased electrolyte leakage in plants subjected to severe stress. However, T. garderiana demonstrated moderate tolerance to water deficit. The plastic changes observed were more physiological than morphological.  Therefore, T. gardneriana seems to be a moderately tolerant species to intermittent drought.

2019 ◽  
Vol 93 ◽  
pp. 204-224 ◽  
Author(s):  
Heather J. Plumpton ◽  
Francis E. Mayle ◽  
Bronwen S. Whitney

AbstractThe Bolivian Chiquitano dry forest is the largest block of intact seasonally dry tropical forest in South America and is a priority ecoregion for conservation due to its high threat status. However, the long-term impacts of drier climatic conditions on tropical dry forests are not well understood, despite climate models predicting increased droughts over Bolivia in the coming century. In this paper, we assess the impacts of drier climatic conditions during the mid-Holocene on the Bolivian Chiquitano tropical dry forest using fossilised pollen, phytoliths, macro-charcoal, and geochemical proxies from a sediment core from a large lake (Laguna Mandioré) on the Bolivia–Brazil border. Our results show that drier climatic conditions during the mid-Holocene caused a local-scale, ecotonal expansion of upland savannah at the expense of dry forest. Interaction between drier climatic conditions and fire regime likely exerted a stronger control over the position of the dry forest–savannah ecotone than edaphic factors. However, the majority of the dry forest within the lake catchment maintained a closed canopy throughout the drier conditions of the mid-Holocene, despite floristic turnover towards more drought-tolerant taxa. These findings imply overall resilience of the Chiquitano dry forest biome to future drought, albeit with floristic changes and upland savannah encroachment at ecotones.


2019 ◽  
Vol 72 (1) ◽  
pp. 8751-8761 ◽  
Author(s):  
Nora Isabel Bravo Baeza ◽  
Luis Fernando Osorio Vélez ◽  
Felipe Bravo Oviedo ◽  
Enrique Martínez Bustamante

The tropical dry forest (TDF) is one of the most affected ecosystems by anthropic activities in the world; so, it is necessary to study the dynamics of its ecosystem in order to restore it. With the aim of determining the survival, development, and photosynthetic behaviors of forest species at a young age, a field study was performed using three species Cedrela odorata L. (Spanish cedar), Pachira quinata (Jacq.) W.S. Alverson (red ceiba) and Ochroma pyramidale (Cav. ex Lam.) Urb. (balsa) species. Field data were collected in different periods whose climatic conditions were: dry period (S.0), first rainy period (Ll.1), first dry period (S.1), second rainy period (Ll. 2), and second dry period (S.2). The total height (H) and the root collar diameter (RCD) were measured repeatedly, and two harvests were made to measure dry weight. Besides, photosynthetic performance and its effect on the species development species during three contrasting rainfall periods was evaluated by measuring photosynthetically active radiation (PAR), stomatal conductance (gs), intercellular carbon (Cint), net photosynthesis (NP), transpiration (trans), efficient water use (EWU) and efficient light use (ELU) from 8:00 and 17:00 h during the day. Analysis of variance was performed obtaining significant differences (P<0.05) in the interaction time×species regarding variables H and RCD, and the photosynthetic variable NP. The gs and trans variables showed statistical significance with the species and rainfall periods; Cint was significant only for the rainfall periods. The species O. pyramidale presented the best survival and tolerance to weather by adapting physiological mechanisms, while C. odorata was the most affected species by climatic conditions concerning overall survival.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 491a-491
Author(s):  
James T. Cole ◽  
Janet C. Cole

An experiment was conducted to evaluate the performance of five ornamental grass species under reduced moisture. This experiment was conducted in the greenhouse with three water treatments for each species: 1) Well-watered plants were irrigated daily throughout the experiment, 2) acclimated-plants were exposed to four drought cycles prior to a final drought period in which measurements were taken, and 3) non-acclimated plants received daily irrigation until undergoing a drought cycle in which measurements were taken. A drought cycle was defined as the time from irrigation until Time Domain Reflectometry (TDR) measured 0 (zero). Preliminary observations determined the plants to be under severe stress, but capable of recovering at TDR measurements of 0. All plants were established from tillers of a single parent for each species. Two plants of each species for the three treatments were established in five blocks. Leaf water potential, osmotic potential, transpiration, stomatal resistance, and relative water content were measured during the drought cycle. At the end of the experiment the leaf area and root and shoot dry weights were determined, root to shoot ratio and leaf area ratio were calculated, and the plants were analyzed for macronutrient and micronutrient contents.


Mycotaxon ◽  
2018 ◽  
Vol 133 (3) ◽  
pp. 499-512 ◽  
Author(s):  
Magdalena Contreras-Pacheco ◽  
Ricardo Valenzuela ◽  
Tania Raymundo ◽  
Leticia Pacheco

2021 ◽  
Vol 490 ◽  
pp. 119127
Author(s):  
Tobias Fremout ◽  
Evert Thomas ◽  
Kelly Tatiana Bocanegra-González ◽  
Carolina Adriana Aguirre-Morales ◽  
Anjuly Tatiana Morillo-Paz ◽  
...  

2016 ◽  
Vol 77 (3) ◽  
pp. 542-552 ◽  
Author(s):  
J. Mertens ◽  
J. Germer ◽  
J. A. Siqueira Filho ◽  
J. Sauerborn

Abstract Spondias tuberosa Arr., a fructiferous tree endemic to the northeast Brazilian tropical dry forest called Caatinga, accounts for numerous benefits for its ecosystem as well as for the dwellers of the Caatinga. The tree serves as feed for pollinators and dispersers as well as fodder for domestic ruminants, and is a source of additional income for local smallholders and their families. Despite its vantages, it is facing several man-made and natural threats, and it is suspected that S. tuberosa could become extinct. Literature review suggests that S. tuberosa suffers a reduced regeneration leading to population decrease. At this juncture S. tuberosa cannot be considered threatened according to the International Union for Conservation of Nature Red List Categories and Criteria, as it has not yet been assessed and hampered generative regeneration is not considered in the IUCN assessment. The combination of threats, however, may have already caused an extinction debt for S. tuberosa. Due to the observed decline in tree density, a thorough assessment of the S. tuberosa population is recommended, as well as a threat assessment throughout the entire Caatinga.


Author(s):  
Kátia F. Rito ◽  
Víctor Arroyo-Rodríguez ◽  
Jeannine Cavender-Bares ◽  
Edgar E. Santo-Silva ◽  
Gustavo Souza ◽  
...  

2003 ◽  
Vol 26 (3) ◽  
pp. 443-450 ◽  
Author(s):  
T. J. BRODRIBB ◽  
N. M. HOLBROOK ◽  
E. J. EDWARDS ◽  
M. V. GUTIÉRREZ

2017 ◽  
Vol 9 (11) ◽  
pp. 283 ◽  
Author(s):  
Renata V. Menezes ◽  
André D. Azevedo Neto ◽  
Hans R. Gheyi ◽  
Alide M. W. Cova ◽  
Hewsley H. B. Silva

Basil (Ocimum basilicum L.) is a medicinal species of Lamiaceae family, popularly known for its multiple benefits and high levels of volatile compounds. The species is considered to be one of the most essential oil producing plants. Also cultivated in Brazil as a condiment plant in home gardens. The objective of this study was to evaluate the effect of salinity on the growth of basil in nutrient solution of Furlani and to identify variables related to the salinity tolerance in this species. The first assay was performed with variation of five saline levels (0 - control, 20, 40, 60 and 80 mM NaCl). In the second assay six genotypes were evaluated in two salinity levels 0 and 80 mM NaCl. The height, stem diameter, number of leaves, dry mass and inorganic solutes in different organs, photosynthetic pigments, absolute membrane integrity and relative water content were evaluated. All biometric variables in basil were significantly reduced by salinity. Dry matter yield and percentage of membrane integrity were the variables that best discriminated the characteristics of salinity tolerance among the studied basil genotypes. Basil genotypes showed a differentiated tolerance among the genotypes, the ‘Toscano folha de alface’ being considered as the most tolerant and ‘Gennaro de menta’ as the most sensitive, among the species studied.


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