Effects of preconditioning on subsequent water relations, stomatal sensitivity, and photosynthesis in osmotically stressed black spruce

1989 ◽  
Vol 67 (8) ◽  
pp. 2240-2244 ◽  
Author(s):  
Janusz J. Zwiazek ◽  
Terence J. Blake
Keyword(s):  
Water Stress ◽  
Water Relations ◽  
Black Spruce ◽  
Water Potentials ◽  
Conditioning Treatment ◽  
Severe Water Stress ◽  
Use Efficiency ◽  
Stomatal Sensitivity ◽  
Stress Conditioning ◽  
Osmotic Potentials

The effects of stress conditioning with polyethylene glycol on water relations and photosynthesis in preconditioned ramets were compared with those of unconditioned black spruce (Picea mariana Mill. BSP). Preconditioned plants maintained lower osmotic and water potentials and higher turgor potentials (measured as a difference between osmotic and water potentials), but photosynthetic rates were similar in both groups of plants. The conditioning treatment increased stomatal sensitivity to water stress, and stomatal conductance was lower in preconditioned plants soon after water stress was imposed. Preconditioned plants maintained significantly lower osmotic potentials during a severe water stress and were able to maintain turgor at the time when unconditioned plants wilted. Water-use efficiency was not affected by stress-conditioning treatment.

scholarly journals Physiological and Yield Responses of Green-Shelled Beans (Phaseolus vulgaris L.) Grown under Restricted Irrigation

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 562
Author(s):  
Karen Campos ◽  
Andrés R. Schwember ◽  
Daniel Machado ◽  
Mónica Ozores-Hampton ◽  
Pilar M. Gil
Keyword(s):  
Water Stress ◽  
Deficit Irrigation ◽  
Pot Experiment ◽  
Water Restriction ◽  
One Pot ◽  
Dry Land ◽  
Severe Water Stress ◽  
The Face ◽  
Use Efficiency ◽  
Yield Responses

Common bean is an important crop, consumed as green-shelled bean in several countries. In Chile, green-shelled beans are cultivated often as a dry land crop, vulnerable to drought. The objective of this study was to characterize the hydric and productive responses of four green-shelled bean genotypes subjected to deficit irrigation in order to outline production strategies in the face of increasing water scarcity. Two experiments were evaluated: one pot experiment with three irrigation treatments, supplying 100% of the crop evapotranspiration (ETc) (T100), 50% (T50), and 30% (T30); and an open field experiment with two treatments: 100% (I100) and 40% of ETc (I40). Treatments were applied during reproductive stage in determinate cultivars and vegetative stage in indeterminate plants. Severe water restriction (T30 and I40) in both experiments showed a significant decrease in stomatal conductances, as well as biomass and number of grains per pod; I40 treatment also showed a reduction in chlorophyll fluorescence. Water use efficiency (WUE) was higher under water stress in field (I40), but lower on the T30 treatment from the pot experiment. Determinate cultivars showed 22.7% higher of 100-seed weight compared to indeterminate type, and, thus, higher tolerance to drought. Our results indicate that severe water stress is highly harmful in terms of yield, and a moderate controlled deficit irrigation plus the use of determinate genotypes may be a strategy for producing green-shelled bean successfully under a drought scenario.

Water Relations of Root-Pruned Jarrah (Eucalyptus marginata Donn ex Smith) Saplings

1987 ◽  
Vol 35 (6) ◽  
pp. 653 ◽  
Author(s):  
DS Crombie ◽  
JT Tippett ◽  
DJ Gorddard
Keyword(s):  
Water Relations ◽  
Phytophthora Cinnamomi ◽  
Leaf Water ◽  
Lateritic Soil ◽  
Root Pruning ◽  
Deep Roots ◽  
Eucalyptus Marginata ◽  
Water Potentials ◽  
Severe Water Stress ◽  
Leaf Shedding

Roots were pruned from jarrah (Eucalyptus marginata Donn ex Smith) saplings to simulate the effects of root loss induced by Phytophthora cinnamomi Rands. Stomatal conductance was more sensitive to root loss than was leaf water potential. Stomatal conductances of trees on moist soils declined when more than 50% of roots were removed but were more variable and were affected more severely by root pruning when soils were dry. Predawn leaf water potentials were unaffected by removal of up to 80% of roots irrespective of whether surface soils were dry or moist. The effects of root pruning on midday water potentials were variable especially when soils were dry. Leaf shedding and efficient stornatal closure prevented severe water stress developing in leaves until nearly 90% of the roots had been removed. It is suggested that destruction of the deep 'sinker' roots by P. cinnamomi has greater effects on jarrah's water relations during summer than does loss of shallow roots. The deep roots are especially important as jarrah grows on highly developed lateritic soil profiles.

scholarly journals Water Stress and Osmotic Adjustment during Post-digging Acclimatization of Quercus virginiana Produced in Fabric Containers

1992 ◽  
Vol 10 (4) ◽  
pp. 208-214
Author(s):  
R.C. Beeson ◽  
E.F. Gilman
Keyword(s):  
Water Stress ◽  
Osmotic Adjustment ◽  
Fine Root ◽  
Early Summer ◽  
Root Weight ◽  
Quercus Virginiana ◽  
Water Potentials ◽  
Live Oak ◽  
Oak Trees ◽  
Osmotic Potentials

Abstract Quercus virginiana Mill. (live oak) trees produced in in-ground 61 cm (24 in) diameter fabric containers were overhead misted and given root ball irrigation after harvesting during early summer. Duration and frequency of overhead misting was reduced to zero over a 3 week period. Water potentials (ΨT) were measured diurnally and osmotic potentials measured from leaves at midday. Intermittent overhead misting was as effective as continuous overhead misting in maintenance of ΨT above −1.0 MPa. Water potentials of −1.5 to −2.0 MPa were measured when the period between overhead misting was expanded from 30 min to 45 min. Osmotic adjustment occurred only in trees receiving overhead misting. Trees receiving only root ball irrigation developed ΨT below −2.5 MPa within 5 days after harvesting. After 3 weeks, ΨT and osmotic potentials were the same for all treatments. In a second experiment, trees were root pruned inside the fabric container 11 weeks before harvest. All root pruned trees survived acclimatization, but only 50% of unpruned trees survived. Water relations were similar to trees in Experiment 1. Surviving trees, both pruned and unpruned, had a significantly higher percentage of fine root weight (roots < 2 mm diameter) than trees that did not survive.

scholarly journals Yield, Mineral Composition, Water Relations, and Water Use Efficiency of Grafted Mini-watermelon Plants Under Deficit Irrigation

HortScience ◽  
2008 ◽  
Vol 43 (3) ◽  
pp. 730-736 ◽  
Author(s):  
Youssef Rouphael ◽  
Mariateresa Cardarelli ◽  
Giuseppe Colla ◽  
Elvira Rea
Keyword(s):  
Water Stress ◽  
Plant Growth ◽  
Water Use Efficiency ◽  
Water Use ◽  
Water Relations ◽  
Fruit Quality ◽  
Stress Conditions ◽  
Irrigated Agriculture ◽  
Marketable Yield ◽  
Use Efficiency

Limited water supply in the Mediterranean region is a major problem in irrigated agriculture. Grafting may enhance drought resistance, plant water use efficiency, and plant growth. An experiment was conducted in two consecutive growing seasons to determine yield, plant growth, fruit quality, leaf gas exchange, water relations, macroelements content in fruits and leaves, and water use efficiency of mini-watermelon plants [Citrullus lanatus (Thunb.) Matsum. and Nakai cv. Ingrid], either ungrafted or grafted onto the commercial rootstock ‘PS 1313’ (Cucurbita maxima Duchesne × Cucurbita moschata Duchesne), under open field conditions. Irrigation treatments were 1.0, 0.75, and 0.5 evapotranspiration rates. In both years (2006 and 2007), marketable yield decreased linearly in response to an increase in water stress. When averaged over year and irrigation rate, the total and marketable yields were higher by 115% and 61% in grafted than in ungrafted plants, respectively. The fruit quality parameters of grafted mini-watermelons such as fruit dry matter and total soluble solids content were similar in comparison with those of ungrafted plants, whereas titratable acidity, K, and Mg concentrations improved significantly. In both grafting combinations, yield water use efficiency (WUEy) increased under water stress conditions with higher WUE values recorded in grafted than ungrafted plants. The concentration of N, K, and Mg in leaves was higher by 7.4%, 25.6%, and 38.8%, respectively, in grafted than in ungrafted plants. The net assimilation of CO2, stomatal conductance, relative water content, leaf, and osmotic potential decreased under water stress conditions. The sensitivity to water stress was similar between grafted and ungrafted plants, and the higher marketable yield from grafted plants was mainly the result of an improvement in nutritional status and higher CO2 assimilation and water uptake from the soil.

Photosynthesis, water relations, and foliar nitrogen of Piceamariana and Larixlaricina from drained and undrained peatlands

1990 ◽  
Vol 20 (7) ◽  
pp. 995-1000 ◽  
Author(s):  
S. Ellen Macdonald ◽  
Victor J. Lieffers
Keyword(s):  
Water Relations ◽  
Black Spruce ◽  
Growing Season ◽  
Foliar Nitrogen ◽  
Initial Effect ◽  
Use Efficiency ◽  
Net Assimilation ◽  
Lower Ratio ◽  
Drainage Effect ◽  
Nitrogen Relations

Rates of net assimilation and related ecophysiological parameters were measured three times during the 1988 growing season on a total of 80 black spruce (Piceamariana (Mill.) B.S.P.) and 80 tamarack (Larixlaricina (Du Roi) K. Koch) trees from two peatland locations, each with paired drained and undrained plots. Ditching for drainage was completed in March 1984. There was no evidence of improved water relations in trees on the drained plots. The initial effect of drainage was the improvement of nitrogen relations. This, in turn, was associated with higher rates of net assimilation. In general, trees in the drained plots were characterized by higher rates of net assimilation, water-use efficiency, mesophyll conductance to CO2, a lower ratio of intercellular to ambient partial pressure of CO2, and higher foliar nitrogen content. For tamarack, the drainage effect was only significant at one location, which was described as the poorer site. For both species, measures of net assimilation and foliar nitrogen were positively correlated with leader growth.

scholarly journals Water Use, Efficiency, and Stomatal Sensitivity in Eastern Cottonwood and Hybrid Poplar Varietals on Contrasting Sites in the Southeastern United States

2021 ◽  
Vol 4 ◽  
Author(s):  
Heidi J. Renninger ◽  
Leah F. Stewart ◽  
Randall J. Rousseau
Keyword(s):  
United States ◽  
Water Stress ◽  
Water Use ◽  
Aboveground Biomass ◽  
Southeastern United States ◽  
Hybrid Poplar ◽  
Eastern Cottonwood ◽  
Use Efficiency ◽  
Stomatal Sensitivity ◽  
Whole Tree

The southeastern United States has wide-scale potential to achieve high productivity from elite eastern cottonwood and hybrid poplar varietals to produce renewable bioenergy and bioproducts. In order to determine how environmental drivers impact water use and growth so that individuals can maintain growth during drought periods, varietals that use water efficiently, and/or tolerate water stress conditions, are needed to make planting recommendations across a variety of sites. Additionally, inoculation with nitrogen-fixing endophytic bacteria may improve water stress tolerance. The goals of this research were (1) to determine water use strategies using measurements of diurnal sapflow and differences in leaf retention for three eastern cottonwood (Populus deltoides, ST66, S7C8, and 110412) and three hybrid poplar (two P. deltoides × Populus maximowiczii, 6329 and 8019, and one Populus trichocarpa × P. deltoides, 5077) varietals on contrasting field sites, (2) determine the physiological impact of endophyte inoculation, and (3) determine which physiological parameters were most highly correlated with aboveground biomass. We found that whole-tree water use efficiency (WUE) was similar across varietals at 5.2 g biomass per kg water used and that water use scaled with tree size. We found that water use strategies in terms of scaled stomatal sensitivity to vapor pressure deficit converged across varietals under stressful soil water conditions at both sites, but that varietals 8019 and 110412 tended to exhibit the highest plasticity in stomatal sensitivity exhibiting the largest range in scaled stomatal sensitivity under different soil moisture conditions. Endophyte inoculation increased growth and stomatal sensitivity at the nitrogen-limited site. Leaf area, whole-tree WUE, and plasticity in stomatal sensitivity were correlated with aboveground biomass production across sites and varietals. Overall, these data can be used to model hydrologic impacts of large-scale Populus biofuel production as well as recommend varietals with efficient water use and stomatal sensitivity under a range of soil and atmospheric moisture stress factors.

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