Different Levels Of Water Deficit Research Articles

Stilbene production as part of drought adaptation mechanisms in cultivated grapevine (Vitis vinifera L.) roots modulates antioxidant status.

Stilbenes, naturally occurring polyphenolic secondary metabolites, play a pivotal role in adaptation of various plant species to biotic and abiotic factors. Recently, increased attention has been directed toward their potential to enhance plant stress tolerance. We evaluated drought tolerance of three grapevine varieties grown with different levels of water deficit. Throughout, we studied physiological mechanisms associated with drought stress tolerance, particularly stilbene accumulation in root tissues, using HPLC. Additionally, we explored the possible relationship between antioxidant potential and stilbene accumulation in response to water deficit. The results underscore the detrimental impact of water deficit on grapevine growth, water status, and membrane stability index, while revealing varying tolerance among the studied genotypes. Notably, Syrah variety had superior drought tolerance, compared to Razegui and Muscat d'Italie grapes. Under severe water deficit, Syrah exhibited a substantial increase in levels of stilbenic compounds, such as t-resveratrol, t-piceatannol, t-ɛ-viniferin, and t-piceid, in root tissues compared to other genotypes. This increase was positively correlated with total antioxidant activity (TAA), emphasizing the active role of resveratrol and its derivatives in total antioxidant potential. This demonstratres the potential involvement of resveratrol and its derivatives in enhancing antioxidant status of the drought-tolerant Syrah grape variety. Our findings suggest that these stilbenes may function as valuable markers in grapevine breeding programs, offering novel insights for the sustainable cultivation of grapevines in water-limited environments.

The impact of biochar addition on morpho-physiological characteristics, yield and water use efficiency of tomato plants under drought and salinity stress

The use of saline water under drought conditions is critical for sustainable agricultural development in arid regions. Biochar is used as a soil amendment to enhance soil properties such as water-holding capacity and the source of nutrition elements of plants. Thus, the research was carried out to assess the impact of biochar treatment on the morphological and physiological characteristics and production of Solanum lycopersicum in greenhouses exposed to drought and saline stresses. The study was structured as a three-factorial in split-split-plot design. There were 16 treatments across three variables: (i) water quality, with freshwater and saline water, with electrical conductivities of 0.9 and 2.4 dS m− 1, respectively; (ii) irrigation level, with 40%, 60%, 80%, and 100% of total evapotranspiration (ETC); (iii) and biochar application, with the addition of biochar at a 3% dosage by (w/w) (BC3%), and a control (BC0%). The findings demonstrated that salt and water deficiency hurt physiological, morphological, and yield characteristics. Conversely, the biochar addition enhanced all characteristics. Growth-related parameters, such as plant height, stem diameter, leaf area, and dry and wet weight, and leaf gas exchange attributes, such rate of transpiration and photosynthesis, conductivity, as well as leaf relative water content were decreased by drought and salt stresses, especially when the irrigation was 60% ETc or 40% ETc. The biochar addition resulted in a substantial enhancement in vegetative growth-related parameters, physiological characteristics, efficiency of water use, yield, as well as reduced proline levels. Tomato yield enhanced by 4%, 16%, 8%, and 3% when irrigation with freshwater at different levels of water deficit (100% ETc, 80% ETc, 60% ETc, and 40% ETc) than control (BC0%). Overall, the use of biochar (3%) combined with freshwater shows the potential to enhance morpho-physiological characteristics, support the development of tomato plants, and improve yield with higher WUE in semi-arid and arid areas.

Morphological performance and seasonal pattern of water relations and gas exchange in Pistacia lentiscus plants subjected to salinity and water deficit.

Soil water deficit and salinity represent a major factor impacting plant survival and agricultural production. The frequency and severity of both abiotic stresses are expected to increase in a context of climate change, especially in arid and semi-arid regions. This work studied the growth pattern, biomass and mineral distribution and the seasonal pattern of water status, photosynthetic rate and stomatal conductance in plant of Pistacia lentiscus grown under different levels of water deficit and salinity. P. lentiscus plants growing under greenhouse conditions were subjected to four irrigation treatments during 11 months: control (C, 1 dS m-1), moderate water deficit (MW, 1dS m-1, 60% of the control), severe water deficit (SW, 1 dS m-1, 40% of the control) and saline (S, 4dS m-1). The results show that Pistacia lentiscus plants were more affected by deficit irrigation than salinity. Deficit irrigation and salinity inhibited plant height, with reductions of 20%, 22% and 35% for S, MW and SW, respectively. Total leaf area was not modified by effect of the treatments, with the result that plant compactness increased in MW. The salt stressed plants only showed lower relative growth rate at the end of the experiment. Plants responded to saline or drought stress by increasing their osmotic adjustment, which was more pronounced under salinity. Saline plants had the highest values in Na+ and Cl- ions and the lowest values for K+/Na+ and Ca2+/Na+ ratios in leaves and stems, which is correlated with a decrease in growth, stomatal conductance, photosynthesis and stem water potential, and can be used as a diagnostic tool to assess plant tolerance to salinity stress. As a measure of plant hydration, relative water content was more sensitive to deficit irrigation than salinity, being a good indicator of water stress. P. lentiscus plants subjected to both deficit irrigation treatments exhibited an increase in their intrinsic water use efficiency, which is an important adaptation for plants growing in environments with water scarcity.

Biochemical responses of sorghum and maize to the impacts of different levels of water deficit and nitrogen supply

Biochemical responses of sorghum and maize to the impacts of different levels of water deficit and nitrogen supply

Water deficit before veraison is crucial in regulating berry VOCs concentration in Sangiovese grapevines.

The impact of water deficit on volatile organic compounds (VOCs) responsible for grape aroma remains quite unclear. The aim of this study was to evaluate the effect of different timing and intensity of water deficit on berry VOCs and on their biosynthetic pathways. Fully irrigated control vines were compared with the following treatments: i) two different levels of water deficit from berry pea-size through veraison, ii) one level of water deficit during the lag-phase, and iii) two different levels of water deficit from veraison through harvest. At harvest, total VOC concentrations were higher in berries of water stressed vines from berry pea size through veraison or during the lag phase, whereas post-veraison water deficit determined similar concentrations as control. This pattern was even more pronounced for the glycosylated fraction and was also observed for single compounds, mainly monoterpenes and C13-norisoprenoids. On the other hand, free VOCs were higher in berries from lag phase or post-veraison stressed vines. The significant glycosylated and free VOCs increment measured after the short water stress limited to the lag phase highlight the pivotal role played by this stage in berry aroma compound biosynthesis modulation. The severity of water stress before veraison was also important, since glycosylated VOCs showed a positive correlation with the pre-veraison daily water stress integral. The RNA-seq analysis showed a wide regulation induced by irrigation regimes on terpenes and carotenoids biosynthetic pathways. The terpene synthases and glycosyltransferases as well as genes of the network of transcription factors were upregulated, especially in berries from pre-veraison stressed vines. Since the timing and intensity of water deficit contribute to regulate berry VOCs, irrigation management can be used to achieve high-quality grapes while saving water.

MicroRNAs expression profiles in early responses to different levels of water deficit in Setaria viridis.

The online version contains supplementary material available at 10.1007/s12298-022-01226-z.

Tracheidogram’s Classification as a New Potential Proxy in High-Resolution Dendroclimatic Reconstructions

Quantitative wood anatomy (QWA) is widely used to resolve a fundamental problem of tree responses to past, ongoing and forecasted climate changes. Potentially, QWA data can be considered as a new proxy source for long-term climate reconstruction with higher temporal resolution than traditional dendroclimatic data. In this paper, we considered a tracheidogram as a set of two interconnected variables describing the dynamics of seasonal variability in the radial cell size and cell wall thickness in conifer trees. We used 1386 cell profiles (tracheidograms) obtained for seven Scots pine (Pinus sylvestris) trees growing in the cold semiarid conditions of Southern Siberia over the years 1813–2018. We developed a “deviation tracheidogram” approach for adequately describing the traits of tree-ring formation in different climate conditions over a long-term time span. Based on the NbClust approach and K-means method, the deviation tracheidograms were reliably split into four clusters (classes) with clear bio-ecological interpretations (from the most favorable growth conditions to worse ones) over the years 1813–2018. It has been shown that the obtained classes of tracheidograms can be directly associated with different levels of water deficit, for both the current and previous growing seasons. The tracheidogram cluster reconstruction shows that the entire 19th century was characterized by considerable water deficit, which has not been revealed by the climate-sensitive tree-ring chronology of the study site. Therefore, the proposed research offers new perspectives for better understanding how tree radial growth responds to changing seasonal climate and a new independent proxy for developing long-term detailed climatic reconstructions through the detailed analysis of long-term archives of QWA data for different conifer species and various forest ecosystems in future research.

Effects of increasing CO2 concentration and water deficit on photosynthetic performance and water use efficiency of typical green manure plants

Exploring the impacts of CO2 and soil water availability on the photosynthetic performance and water use efficiency of three green manure plants could provide theoretical basis for the adaptive management of grassland ecosystems under future climate change. An experiment was conducted in an artificial climate chamber with precisely controled CO2 concentrations of 400 (natural atmospheric) and 800 μmol·mol-1 (doubled), and four water treatments, 80% field water holding capacity (FC) (full irrigation control group), 55%-60% FC (mild water deficit), 35%-40% FC (moderate water deficit), <35% FC (severe water deficit) to investigate the impacts of increasing CO2 concentration and water deficit on chlorophyll content, gas exchange variables, and water use efficiency (WUE) of oilseed rape (Brassica napus), white clover (Trifolium repens), and alfalfa (Medicago sativa). The results showed that under the same CO2 concentration, when soil moisture was less than 40% FC, the chlorophyll content and gas exchange parameters of three plants were significantly decreased. The treatment of 55%-60% FC did not alter the total chlorophyll content of three species, but reduced the photosynthetic rate (Pn) and transpiration rate (Tr) of white clover and alfalfa by 6%-25% and did not affect their WUE. Compared with atmospheric CO2 concentration, the doubled CO2 concentration significantly decreased the Pn of oilseed rape by 21.5% under the full irrigation treatment, increased the Pn of three species under mild water deficit, increased the Pn of oilseed rape and alfalfa under moderate water deficit, but only improved the Pn of alfalfa under severe water deficit. The doubled CO2 concentration significantly increased WUE of white clover and alfalfa under all water deficit conditions, but only increased WUE of oilseed rape under mild water deficit. Increasing CO2 concentration and water deficit significantly interacted to affect Pn of three species and the WUE of oilseed rape. In summary, the three species differed in their responses to doubled atmospheric CO2 concentration and different levels of water deficit. Our results suggested that elevated CO2 concentration could improve the adverse effects of mild water deficit on photosynthetic performance and WUE of three species, but only improve the photosynthetic performance of alfalfa under severe water deficit.

The combined effect of water deficit stress and TiO2 nanoparticles on cell membrane and antioxidant enzymes in Helianthus annuus L.

Nanotechnology has become one of the several approaches attempting to ameliorate the severe effect of drought on plant's production and to increase the plants tolerance against water deficit for the water economy. In this research, the effect of foliar application of TiO2, nanoparticles or ordinary TiO2, on Helianthus annuus subjected to different levels of water deficit was studied. Cell membrane injury increased by increasing the level of water deficit and TiO2 concentration, and both types of TiO2 affected the leaves in analogous manner. Ord-TiO2 increased H2O2 generation by 67–240% and lipid peroxidation by 4–67% in leaves. These increases were more than that induced by Nano-TiO2 and the effect was concentration dependent. Proline significantly increased in leaves by water deficit stress, reaching at 25% field capacity (FC) to more than fivefold compared to that in plants grown on full FC. Spraying plants with water significantly decreased the activities of enzymes in the water deficit stressed roots. The water deficit stress exerted the highest magnitude of effect on the changes of cell membrane injury, MDA, proline content, and activities of CAT and GPX. Nano-TiO2 was having the highest effect on contents of H2O2 and GPX activity. In roots, the level of water deficit causes highest effect on enzyme activities, but TiO2 influenced more on the changes of MDA and H2O2 contents. GPX activity increased by 283% in leaves of plants treated with 50 and 150 ppm Nano-TiO2, while increased by 170% in those treated with Ord-TiO2, but APX and CAT activities increased by 17–197%, in average, with Ord-TiO2. This study concluded that Nano-TiO2 didn’t ameliorate the effects of drought stress on H. annuus but additively increased the stress, so its use in nano-phytotechnology mustn’t be expanded without extensive studies.

Detection of Epistasis for Seed and Some Phytochemical Traits in Coriander under Different Irrigation Regimes

Coriander (Coriander sativum L.) is an annual herb mainly cultivated for its seed characteristics. Drought stress is a major problem which affects coriander behaviour through biochemical responses. This study aimed to determine the nature and magnitude of epistasis in inheritance of seed yield (SY), percent of dehulled seed (PODS), percent of seed hulls (POSH), essential oil content (EOC), essential oil yield (EOY), dehulled seed fatty acid content (DSFAC), hull fatty acid content (HFAC), fatty acid content (FAC), and fatty acid yield (FAY), and to estimate additive and dominance variance for the traits not influenced by epistasic effects. Three testers, TN-59-158 (highly drought-susceptible), TN-58-230 (highly drought-tolerant, but low-yielding), and their F1 hybrid were each crossed for six genotypes. The experiment was performed under different levels of water deficit: control (C), moderate water deficit (MWD), and severe water deficit (SWD) conditions. Epistasis affected the expression of SY, EOC, EOY, FAC, and FAY in all water conditions, PODS in C, POSH in SWD, HFAC in MWD, and DSFAC in both C and MWD conditions. Total epistasic effects were partitioned, showing that both [i] and [j + l] type interactions were significant, with a prevalent influence of [i] type interactions on these traits except for POSH and FAC in the SWD condition, which exhibited a higher value of the [j + l] type. Both additive and non-additive gene actions were significant for those traits not significantly affected by epistasis in C, MWD, or SWD conditions. An additive type of gene action was preponderant for PODS in MWD and SWD, POSH in MWD, DSFAC in SWD, and HFAC in C and SWD conditions.

Differential Response to Water Deficit in Chili Pepper (Capsicum annuum L.) Growing in Two Types of Soil Under Different Irrigation Regimes

Chili pepper (Capsicum spp.) is one of the most economically important horticultural crops in the world; its production for the food and pharmaceutical industries has been increasing worldwide. The economic importance of this crop is due, in part, to the nutraceutical properties derived from its secondary metabolism. Drought is the main environmental factor that affects crop production. Nevertheless, studies involving water deficit have considered short-term responses to sharp water deficit rather than long-term acclimation processes through moderate and gradually increasing water deficits, which omitted the dynamics and profile of the secondary metabolism that are part of the plant’s defence system against this stress factor. The present study aimed to identify the different mechanisms that chili pepper plants use to cope with drought stress using a progressive decrease and increase of water availability, conditions that commonly occur for crops in open fields. Four treatments were applied as follows: gradual water deficit (GWD), initial waterlogging with gradual water deficit (IWGD), sudden water deficit with gradual recovery (SWDR), and no deficit of water (NDW). These conditions should represent a more real situation similar to that faced by plants in the agricultural environment. In order to evaluate the response mechanisms associated with these water deficits, changes in phenological variables, proline accumulation, and the gene expression of phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), peroxidase (POD), and superoxide dismutase (SOD) were measured in chili pepper plants growing on land under different irrigation regimes in two contrasting soil types in areas where chili pepper plants are cultivated in central Mexico. The variables evaluated showed a differentiated response of the mechanisms in plants growing under different levels of water deficit. Given the differential response observed for the gene expression and morphological and biochemical variables studied in chili pepper plants against different water regimes, in this work, this may have implications for more efficient use of water in crops with high nutraceutical content, in addition to prospects for using products derived from secondary metabolism in the pharmaceutical industry.

MODELING YIELD, SOIL WATER BALANCE, AND ECONOMIC RETURN OF SOYBEAN UNDER DIFFERENT WATER DEFICIT LEVELS

ABSTRACT Evaluating the impacts of water stress on crop yield allows comparing irrigation management alternatives, aiming to ensure an economic return for the irrigated farms. Thus, the main objectives of this study were to model the soil water balance, deriving the crop coefficients, grain yield prediction, and economic return of soybean grown at different levels of water deficit and price quotations. The experiment was carried out under a rainout shelter, using four irrigation water managements. Irrigations were applied when the soil available water in the root zone reached 75%, 64%, 60%, and 50% of the total available water (TAW). Crop and soil parameters were monitored throughout the crop season. The SIMDualKc model was used to simulate the soil water balance. Statistics indicators demonstrated the goodness of the simulation, with regression coefficients (b0) ranging from 0.96 and 0.99 and root mean square errors (RMSE) ≤8.4 mm. Crop coefficients for initial, intermediate, and final stages were calibrated and validated at 0.15, 1.00, and 0.10, respectively. Crop yield and economic return were higher for the treatment kept at 75% of TAW, results that should be considered in irrigation management programs.

Spermine-priming restrained water relations and biochemical deteriorations prompted by water deficit on two soybean cultivars

The outstanding role of spermine in eliciting defense adaptation of soybean to different levels of water deficit (0, -0.1, -0.5 and -1.1 MPa) was investigated by determining the changes in growth, photosynthetic pigments, osmolytes, water relations, and antioxidants. All the studied traits clearly revealed cultivar-dependent variation in response to water deficit where cv. Giza 111 was tolerant and cv. Giza 21 was sensitive. Both cultivars came in agreement that photosynthetic limitation (chlorophylls reduction) was the troubling shot induced by water deficit. Such limitation was reflected on three directions (a) disturbances of water relations (stomatal conductance, transpiration rate, relative water content and water use efficiency), (b) down regulation of metabolites which affect osmotic adjustment and (c) elevated reactive oxygen species (increased hydrogen peroxide) and destruction of membrane stability (increment of electrolyte leakage and lipid peroxidation). The damaging impacts of water deficit on these parameters were obviously coined for sensitive cultivar compared to tolerant one. Although spermine priming did not have apparent stimulatory role on well-watered plants, unequivocal inversion from a state of down regulation to up-regulation was distinct under water stress. In this regard, spermine enhanced pigments, osmolytes accumulation, up-regulated water relations and enhanced membrane stabilization. Furthermore, spermine pre-sowing decreased oxidative stress by lowering hydrogen peroxide via activation of anthocyanins, total antioxidants and phenolic compounds.

Osmolyte accumulation and antioxidant metabolism during germination of vigorous maize seeds subjected to water deficit

The objective of this work was to evaluate the alterations of antioxidant enzyme reserves and antioxidant enzymes during germination under water deficit in maize hybrids and to associate with seed vigor, determining the mechanisms related to tolerance for this stress. Two three-way maize hybrids were characterized by their vigor at different levels of water deficit induced by polyethylene glycol 6000. Next, the seeds were hydrated at different osmotic potentials (0.0, -0.3, and -0.9 MPa) and removed at different times to assess the levels of the total soluble protein, total soluble sugars, proline, starch, and antioxidant enzymes, such as superoxide dismutase, catalase and ascorbate peroxidase. The analysis of variance, Tukey test at 5% and principal component analysis (PCA) were used. The vigorous hybrid (HT1) was more efficient than the low vigor hybrid seeds (HT2) in mobilizing the total soluble protein during the initial stages of germination and the total soluble sugars before and after root protrusion under water deficit in addition to increasing the catalase activity at the different osmotic potentials that were assessed.

Parameterization and comparison of the AquaCrop and MOPECO models for a high-yielding barley cultivar under different irrigation levels

This study describes the processes of calibration and validation of AquaCrop (the FAO water productivity model) and MOPECO (economic optimization model of irrigation water) for the simulation of a barley crop (cv. Cierzo). We compare the complexity of implementing this process in the two models and the accuracy of the results. A 3-year field experiment conducted during the period from 2011 to 2013 in a semi-arid region located in southeast Spain was used for this purpose. Six irrigation treatments were applied combining different levels of water deficit depending on the phenological stage. Both models were suitable for the simulation of yield and soil moisture evolution. In addition, AquaCrop correctly simulated the harvest index, the evolution of canopy cover and aboveground biomass. The comparison between the two models showed that AquaCrop is a better model for assessing the effect of a particular irrigation schedule on a crop (i.e. biomass and canopy cover development, soil water balance…) than MOPECO. Nevertheless, if the objective is to estimate yield depending on the irrigation schedule applied, MOPECO is easier to calibrate and furnishes results as valid as those provided by AquaCrop.

Toward a generalized predictive model of grapevine water status in Douro region from hyperspectral data

The predawn leaf water potential (ѱpd) is an eco-physiological indicator widely used for assessing vines water status and thus supporting irrigation management in several wine regions worldwide. However, the ѱpd is measured in a short time period before sunrise and the collection of a large sample of points is necessary to adequately represent a vineyard, which constitute operational constraints. In the present study, an alternative method based on hyperspectral data derived from a handheld spectroradiometer and machine learning algorithms was tested and validated for assessing grapevine water status. Two test sites in Douro wine region, integrating three grapevine cultivars, were studied for the years of 2014, 2015, and 2017. Four machine learning regression algorithms were tested for predicting the ѱpd as a continuous variable, namely Random Forest (RF), Bagging Trees (BT), Gaussian Process Regression (GPR), and Variational Heteroscedastic Gaussian Process Regression (VH-GPR). Three predicting variables, including two vegetation indices (NRI554,561 and WI900,970) and a time-dynamic variable based on the ѱpd (ѱpd_0), were applied for modelling the response variable (ѱpd). Additionally, the predicted values of ѱpd were aggregated into three classes representing different levels of water deficit (low, moderate, and high) and compared with the corresponding classes of ѱpd observed values. A root mean square error (RMSE) and a mean absolute error (MAE) lower or equal than 0.15 MPa and 0.12 MPa, respectively, were obtained with an external validation data set (n = 71 observations) for the various algorithms. When the modelling results were assessed through classes of values, a high overall accuracy was obtained for all the algorithms (82–83%), with prediction accuracy by class ranging between 79% and 100%. These results show a good performance of the predictive models, which considered a large variability of climatic, environmental, and agronomic conditions, and included various grape cultivars. By predicting both continuous values of ѱpd and classes of ѱpd, the approach presented in this study allowed obtaining 2-levels of accurate information about vines water status, which can be used to feed management decisions of different types of stakeholders.

Effect of Water Stress during Grain Filling on Yield, Quality and Physiological Traits of Illpa and Rainbow Quinoa (Chenopodium quinoa Willd.) Cultivars.

The total area under quinoa (Chenopodium quinoa Willd.) cultivation and the consumption of its grain have increased in recent years because of its nutritional properties and ability to grow under adverse conditions, such as drought. Climate change scenarios predict extended periods of drought and this has emphasized the need for new crops that are tolerant to these conditions. The main goal of this work was to evaluate crop yield and quality parameters and to characterize the physiology of two varieties of quinoa grown under water deficit in greenhouse conditions. Two varieties of quinoa from the Chilean coast (Rainbow) and altiplano (Illpa) were used, grown under full irrigation or two different levels of water deficit applied during the grain filling period. There were no marked differences in yield and quality parameters between treatments, but the root biomass was higher in plants grown under severe water deficit conditions compared to control. Photosynthesis, transpiration and stomatal conductance decreased with increased water stress in both cultivars, but the coastal variety showed higher water use efficiency and less discrimination of 13C under water deficit. This response was associated with greater root development and a better stomatal opening adjustment, especially in the case of Rainbow. The capacity of Rainbow to increase its osmoregulant content (compounds such as proline, glutamine, glutamate, K and Na) could enable a potential osmotic adjustment in this variety. Moreover, the lower stomatal opening and transpiration rates were also associated with higher leaf ABA concentration values detected in Rainbow. We found negative logarithmic relationships between stomatal conductance and leaf ABA concentration in both varieties, with significant R2 values of 0.50 and 0.22 in Rainbow and Illpa, respectively. These moderate-to-medium values suggest that, in addition to ABA signaling, other causes for stomatal closure in quinoa under drought such as hydraulic regulation may play a role. In conclusion, this work showed that two quinoa cultivars use different strategies in the face of water deficit stress, and these prevent decreases in grain yield and quality under drought conditions.

Application of deficit irrigation in Phillyrea angustifolia for landscaping purposes

Phillyrea angustifolia is an evergreen shrub of interest for urban landscape design, as well as for use in revegetation projects in Mediterranean areas, which are characterized by an acute scarcity of water. The effect of different levels of water deficit on several physiological, ornamental and morphological parameters of Phillyrea angustifolia plants was studied to evaluate their adaptability to xerogarden and/or landscape conditions. Nursery grown plants were subjected to three irrigation treatments: a control (watered to container capacity) and two deficit irrigation treatments of 60 and 40% of the amount of water supplied in the control treatment (moderate and severe deficit irrigation). After 23 months, plant height was significantly inhibited by both water deficit treatments, although plant compactness (foliar area in relation to plant height) was not affected. Plants under severe deficit irrigation increased their root to shoot ratio and water use efficiency, which are positive aspects for hardening. Plants exposed to both deficit irrigation treatments exhibited slight dehydration throughout the experiment, especially in spring, as indicated by the lower leaf water potential and relative water content. The tolerance of P. angustifolia to drought was mainly related to adjust osmotic and regulated stomatal closure. It is concluded that both deficit irrigation treatments can be used successfully in P. angustifolia plant production to reduce water consumption while maintaining good overall quality. Moderate deficit irrigation is specially recommended for gardening purposes, since this treatment produced plants with of visual quality. Severe deficit irrigation is more suitable for landscaping purposes, as an effective nursery technique to produce plants better adapted to environmental stress during transplanting.

Effects of Different Levels of Water Deficit on the Soil in Chrysanthemum Culture

Effects of Different Levels of Water Deficit on the Soil in Chrysanthemum Culture

Growth of the common bean submitted at different levels of water deficit in the soil

The objective of this study was to evaluate the effect of water deficit on thegrowth of common bean cultivated in medium and clayey soil. Two experiments were developed in factorial scheme of 2 x 4 with tension for the determination of field capacity on two levels and soil water deficit on four levels in a completelyrandomized design with three replicates for each soil. Growth analyzes were performed in two phenological stage of crop and the data were submitted to an analysis of variance (p ≤ 0.05). When significant, the F Test (p ≤ 0.05) was used for the qualitative factor and regression analysis for the quantitative factor. The water content in the soil of 40 and 60% of available water exertednegative effects on leaf water potential, leaf area and total dry matter of thecommon bean, independent of voltage adopted in determining the field capacity.