scholarly journals ESTABLISHMENT OF YOUNG “DWARF GREEN” COCONUT PLANTS IN SOIL AFFECTED BY SALTS AND UNDER WATER DEFICIT

2016 ◽  
Vol 38 (3) ◽  
Author(s):  
ALEXANDRE REUBER ALMEIDA DA SILVA ◽  
FRANCISCO MARCUS LIMA BEZERRA ◽  
CLAUDIVAN FEITOSA DE LACERDA ◽  
MARIA EMÍLIA BEZERRA DE ARAÚJO ◽  
RONNEY MENDES MAGALHÃES DE LIMA ◽  
...  

ABSTRACT The aim was to analyze the establishment of young “Green Dwarf” coconut plants in soils affected by salts and under water stress, by evaluating leaf area, biomass production and allocation. In the experiment, conducted in protected environment in Fortaleza, CE, in statistical design of randomized blocks in a split plot arrangement, the effects of different water deficit levels (plots) were evaluated, by imposing different percentages of replacement of water losses by potential crop evapotranspiration - ETpc (20, 40, 60, 80 and 100%), associated with subplots consisting of increasing soil salinity levels (1.72, 6.25, 25.80 and 40.70 dS m-1) provided by soil collected at different parts of the Morada Nova Irrigated Perimeter - PIMN. Leaf area and biomass production were sharply reduced by the conditions of water stress and high soil salinity, apparently being more critical to the crop under water restriction condition. The degree of water stress can increase the susceptibility to salinity and plants can be considered, in general terms, as moderately tolerant to the effects of salinity, when combined with water deficiency. Coconut seedlings show full capacity of establishment in PIMN saline soils, corresponding to the level of electrical conductivity of 6.50 dS m-1, but only when the water supply remains adequate. For higher salinity levels, plants survive, but their size is reduced by around 50%, even when fully irrigated.

2017 ◽  
Vol 45 (1) ◽  
pp. 238-244 ◽  
Author(s):  
Udson de Oliveira BARROS JUNIOR ◽  
Maria Antonia Machado BARBOSA ◽  
Michael Douglas Roque LIMA ◽  
Gélia Dinah Monteiro VIANA ◽  
Allan Klynger da Silva LOBATO

Low water supply frequently interferes on chlorophyll fluorescence and gas exchange. This study aimed to answer if a short-time of rehydration is efficient to re-establish chlorophyll fluorescence and gas exchange in cowpea plants. The experiment used four treatments (sensitive / water deficit, sensitive / control, tolerant / water deficit and tolerant / control). The sensitive and tolerant cultivars after water restriction had significant changes in gas exchange. On the third day, the stress caused lower for PN and gs in sensitive cultivar of 67% and 45%, respectively. After rehydration these parameters were not recovered significantly to two cultivars. In relation to chlorophyll fluorescence, water stress caused significant changes in all parameters evaluated of cultivars, being observed effects more intense on sensitive cultivar in the parameters Fv/Fm (38%) and Fo (69%). Rehydration did not promote recovery of the values of Fv/Fm and Fo to sensitive cultivar. Therefore, our study revealed that a short-time of rehydration is not effective to re-establish chlorophyll fluorescence and gas exchange in cowpea plants submitted to water deficit.


2018 ◽  
Vol 69 (6) ◽  
pp. 594 ◽  
Author(s):  
Goudarz Ahmadvand ◽  
Somayeh Hajinia

Piriformospora indica is one of the cultivable root-colonising endophytic fungi of the order Sebacinales, which efficiently promote plant growth, uptake of nutrients, and resistance to biotic and abiotic stresses. The aim of this study was to evaluate the effect of P. indica on millet (Panicum miliaceum L.) under water-stress conditions. Two field experiments were carried out in a factorial arrangement at Bu-Ali Sina University of Hamedan, Iran, during 2014 and 2015. The first factor was three levels of water-deficit stress, with irrigation after 60 mm (well-watered), 90 mm (mild stress) and 120 mm (severe stress) evaporation from pan class A. The second factor was two levels of fungus P. indica: inoculated and uninoculated. Results showed that water-deficit stress significantly decreased grain yield and yield components. Colonisation by P. indica significantly increased number of panicles per plant, number of grains per panicle and 1000-grain weight, regardless of water supply. Inoculation with P. indica increased grain yield by 11.4% (year 1) and 19.72% (year 2) in well-watered conditions and by 35.34% (year 1) and 32.59% (year 2) under drought stress, compared with uninoculated plants. Maximum flag-leaf area (21.71 cm2) was achieved with well-watered conditions. Severe water stress decreased flag-leaf area by 53.36%. Flag-leaf area was increased by 18.64% by fungus inoculation compared with the uninoculated control. Under drought conditions, inoculation with P. indica increased plant height by 27.07% and panicle length by 9.61%. Severe water stress caused a significant decrease in grain phosphorus concentration, by 42.42%, compared with the well-watered treatment. By contrast, grain nitrogen and protein contents were increased about 30.23% and 30.18%, respectively, with severe water stress. Inoculation with P. indica increased grain phosphorus by 24.22%, nitrogen by 7.47% and protein content by 7.54% compared with control. Water stress reduced leaf chlorophyll and carotenoid concentrations, whereas P. indica inoculation enhanced chlorophyll concentrations by 27.18% under severe water stress. The results indicated the positive effect of P. indica on yield and physiological traits of millet in both well-watered and water-stressed conditions.


2017 ◽  
Vol 30 (2) ◽  
pp. 447-457 ◽  
Author(s):  
ALEXANDRE REUBER ALMEIDA DA SILVA ◽  
FRANCISCO MARCUS LIMA BEZERRA ◽  
CLAUDIVAN FEITOSA DE LACERDA ◽  
CARLOS HENRIQUE CARVALHO DE SOUSA ◽  
MARLOS ALVES BEZERRA

ABSTRACT The objective of this study was to characterize the physiological acclimation responses of young plants of the dwarf coconut cultivar Jiqui Green‘ associated with tolerance to conditions of multiple abiotic stresses (drought and soil salinity), acting either independently or in combination. The study was conducted under controlled conditions and evaluated the following parameters: leaf gas exchange, quantum yield of chlorophyll a fluorescence, and relative contents of total chlorophyll (SPAD index). The experiment was conducted under a randomized block experimental design, in a split plot arrangement. In the plots, plants were exposed to different levels of water stress, by imposing potential crop evapotranspiration replacement levels equivalent to 100%, 80%, 60%, 40%, and 20%, whereas in subplots, plants were exposed to different levels of soil salinity (1.72, 6.25, 25.80, and 40.70 dS m-1). Physiological mechanisms were effectively limited when water deficit and salinity acted separately and/or together. Compared with soil salinity, water stress was more effective in reducing the measured physiological parameters. The magnitudes of the responses of plants to water supply and salinity depended on the intensity of stress and evaluation period. The physiological acclimation responses of plants were mainly related to stomatal regulation. The coconut tree has a number of physiological adjustment mechanisms that give the species partial tolerance to drought stress and/or salt, thereby enabling it to revegetate salinated areas, provided that its water requirements are at least partially met.


2004 ◽  
Vol 61 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Paulo Torres Carneiro ◽  
Pedro Dantas Fernandes ◽  
Hans Raj Gheyi ◽  
Frederico Antônio Loureiro Soares ◽  
Sergio Batista Assis Viana

The cashew crop (Anacardium occiedentale L.) is of great economic and social importance for Northeast Brazil, a region usually affected by water and soil salinity. The present study was conducted in a greenhouse to evaluate the effects of four salinity levels established through electrical conductivity of irrigation water (ECw: 0.7, 1.4, 2.1 and 2.8 dS m-1, at 25ºC), on growth and physiological indexes of five rootstocks of dwarf-precocious cashew varieties CCP06, CCP09, CCP1001, EMBRAPA50, and EMBRAPA51. Plant height, leaf area, dry weight of root, shoot and total; water content of leaves, root/shoot ratio, leaf area ratio, absolute and relative growth rates and rate of net assimilation were evaluated. The majority of the evaluated variables were found to be affected by ECw and the effects varied among clones; however, no significant interactive effects were observed for factors. The value of ECw = 1.39 dS m-1 was considered as a threshold tolerance for the precocious cashew rootstocks used in this study. The dwarf-precocious cashew is moderately sensible to soil salinity during the formation phase of rootstock. Clones EMBRAPA51 and EMBRAPA50 presented, respectively, the least and the best development indexes.


2015 ◽  
Vol 42 (12) ◽  
pp. 1116 ◽  
Author(s):  
Benoît Pallas ◽  
Angélique Christophe

The relationships between whole-plant growth and morphogenetic processes under abiotic stresses are still partly unknown. Whole-plant biomass growth can be decreased by many abiotic stresses, including water deficit and shading. Two experiments were performed on potted plants of one grapevine cultivar (Vitis vinifera L. cv. Syrah) subjected to watering and shading treatments. Under water stress, plants reduced their primary and secondary axis leaf production rate, whereas secondary axis budburst was relatively unaffected. Individual leaf area was reduced and a strong decrease in leaf expansion rate was observed. Under shading, primary axis organogenesis was maintained, both secondary axis budburst rate and phytomer appearance rate were decreased, and individual leaf area slightly increased. Specific leaf area did not change under soil water deficit, whereas it increased under shading. These results confirm the existence of dynamic changes in organ sink strength and biomass allocation patterns to favour plant leaf area growth under shading, and to reduce plant leaf area and water losses by transpiration under water stress. From a modelling point of view, this study shows that functional structural models based on a C balance are not fully relevant for simulating plant growth under abiotic constraints if they do not include non-trophic relationships (hormonal signalling or plant hydraulic properties) that modify organ sink strength according to abiotic constraints.


2016 ◽  
Vol 34 (4) ◽  
pp. 701-708 ◽  
Author(s):  
M.F.P. LIMA ◽  
J.L.D. DOMBROSKI ◽  
F.C.L. FREITAS ◽  
J.R.S. PINTO ◽  
D.V. SILVA

ABSTRACT The capacity of a weed to adapt to the restriction of growth factors is directly related to its ability to compete for those resources with the cultivated species. An experiment was conducted to evaluate the effect of water restriction on the growth and biomass partitioning of four species of weeds. The experimental design used randomized blocks, with five replications. The treatments were arranged in a 4 x 2 factorial, with the first factor being the weed species (Waltheria indica, Crotalaria retusa, Cleome affinis and Commelina benghalensis) and the second, two water regimes: daily irrigation (Irr) and water restriction (WR). The number of leaves, leaf area, dry mass of the plant and its parts (root, stem and leaf), and the mass distribution among different organs (roots, leaves and stems) were determined. The water deficit in the soil increased the root dry matter for C. retusa, W. indica and C. benghalensis, however, it did not alter the mass of the stem of the weeds. C. retusa and W. indica suffered a reduction on the number of leaves, leaf area, dry matter of the leaves and the plant dry matter under water deficit. W. indica and C. retusa had a reduction on the percentage of biomass allocated to the leaves, and an increment on the percentage of the roots mass, while C. benghalensis and C. affinis had an increase only on the roots mass.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 857C-857
Author(s):  
Alireza Talaie* ◽  
Vali Rabiei ◽  
Ali Ebadi

Grapevine under arid and semi-arid are subjected to low soil water availability, accompanied by high levels of temperature and severe transpiration in the summer period. In spite of their deep root system, severe water stress may occur during that period. Therefore, study of morphological and physiological responses of grapevine cultivars to water stress, especially during the different phenological stages, are necessary. The effect of water deficit stress on morphological and physiological responses of four Iranian grapevine cultivars (Vitis vinifera L. cvs. Bidaneh Sephid, Yaghooti Shiraz, Khoshnav, and Siaveh) were studied. This investigation was conducted as a factorial experiment in a complete randomized block design with four replications. In this study, 1-year-old own rooted vines were planted outdoor in plastic bags. Water stress was begun 115 days after bud break and contained for 2 months. Some vegetative and biochemical characters of leaves were evaluated; photosynthesis and gas exchange was measured. The results of analysis of variance indicated that water deficit stress decreased total dry weight, root dry weight, leaf area, non soluble carbohydrate concentration, and chlorophyll content. The reduction of leaf area in `Yaghooti Shiraz' and total dry weight and root dry weight in `Bidaneh Sephid' were higher than two other cultivars. Under water deficit stress condition, the soluble carbohydrate concentration and proline content in grapevine cultivars increased. Net photosynthesis and gas exchange rate were markedly reduced in water deficit stressed vines.


Author(s):  
Ranjan Das, Kaushik Bhagawati, Alpana Boro, Tulika Medhi

Among the environmental stresses, water deficit stress was recognized to be one of the most adverse factors for plant growth and productivity. The study aimed to comparatively evaluate impact of water deficit stress on biomass of seven cultivars of gladiolus in terms of leaf area duration and net assimilation rate under rainfed conditions in northeastern region of India. Also, productions in terms of marketable spikes were compared. The parameters were measured using standard procedures. Comparatively higher leaf area duration (116 days) and net assimilation rate were found in cultivars Aarti (116 days and1.62 gcm-2day-1x10-3 respectively) and Suchitra (98.0 days and 1.10 gcm-2day-1x10-3) which account for their higher biomass production with larger spike size with good numbers of flowers. The highest marketable spikes (71111.11 spikes ha-1) was found in cultivar Aarti followed by Suchitra (68148.14 spikes ha-1) which might be due to its comparatively higher biomass production and less deviation, during stress condition, from normal characteristics. The tolerant cultivars are those that can adapt to the change without much change in their normal growth. And the responses of those species are commercially acceptable that promote adaptation without compromising much with the plant growth and crop production.


Author(s):  
Alexandre R. A. da Silva ◽  
Francisco M. L. Bezerra ◽  
Claudivan F. de Lacerda ◽  
Rafael de S. Miranda ◽  
Elton C. Marques ◽  
...  

ABSTRACT The objective of this study was to investigate the biochemical mechanisms associated with isolated and/or concurrent actions of drought and soil salinity in seedlings of coconut tree, through the accumulation of organic solutes (soluble carbohydrates, soluble amino N and free proline) in leaves and roots. The experiment, conducted in a protected environment, in Fortaleza, Brazil, in a randomized block design, in a split-plot arrangement, evaluated the effects of different levels of water stress (plots) by imposing distinct percentages of replacement of water losses through crop potential evapotranspiration - ETpc (20, 40, 60, 80 and 100%), associated with subplots consisting of increasing levels of soil salinity in saturation extract (1.72, 6.25, 25.80 and 40.70 dS m-1) provided by the soils collected in the Irrigated Perimeter of Morada Nova. Salinity did not change the concentration of organic solutes; however, there were increases in leaf and root levels of free proline in response to water stress, which contributes to the osmoregulation and/or osmoprotection of the species under adverse conditions of water supply.


2020 ◽  
Vol 12 (1) ◽  
pp. 42-56
Author(s):  
Hugo THANER DOS SANTOS ◽  
Renata ALCARDE SERMARINI ◽  
Maria A. MORENO-PIZANI ◽  
Patricia A. ALVES MARQUES

The responses of oregano plants to water limitation from soil and seasonal phenological cycle are not fully understood yet. The aim of the present research was to help understanding the production of oregano essential oil and biomass facing soil water deficit, which was studied in different seasons. Oregano was subjected to drip irrigation, the water deficit being assessed in the vegetative and pre-flowering stages, as well as whole cycle analysis, through water matric potentials in the soil. The matric potential -60.8 kPa adopted in the irrigation handling during the oregano cultivation interval, led to higher essential oil content and yield. The same potential applied during the oregano pre-flowering stage resulted in the best mean of oregano fresh biomass production. The best dry biomass production was reached by using the matric potential -91.2 kPa in the oregano pre-flowering irrigation management. Water restriction in the soil throughout the entire phenological cycle favored essential oil production, whereas the water restriction during the pre-flowering stage enabled high oregano dry biomass production. The highest values for biomass and essential oil productions were reached for the oregano plants cultivated during spring/summer.


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