The Role of Active and Passive Water Uptake in Maintaining Leaf Water Status and Photosynthesis in Tomato under Water Deficit

2000 ◽  
Vol 3 (3) ◽  
pp. 296-298 ◽  
Author(s):  
Jen-Hsien Weng
Keyword(s):  
Water Deficit ◽  
Water Uptake ◽  
Water Status ◽  
Leaf Water ◽  
Leaf Water Status

Abscisic Acid Levels in Nacl-Treated Barley, Cotton and Saltbush

1991 ◽  
Vol 18 (1) ◽  
pp. 17 ◽  
Author(s):  
Z Kefu ◽  
R Munns ◽  
RW King
Keyword(s):  
Abscisic Acid ◽  
Water Deficit ◽  
Water Status ◽  
Xylem Sap ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Cotton Plants ◽  
Presence And Absence ◽  
Leaf Water Deficit

Exposing barley and cotton plants to 75 mol m-3 NaCl reduced transpiration and increased abscisic acid (ABA) levels in leaves, roots and xylem sap. Exposing saltbush (Atriplex spongiosa) plants to 75 mol m-3 NaCI, at which concentration they grow best, did not affect transpiration or ABA levels but when the NaCl was increased to 150 mol m-3 transpiration fell and ABA levels rose. ABA levels in leaves were high in salt-treated barley and saltbush even when the leaf water status was raised by pressurising the roots. These responses indicate that an increased leaf ABA level was not triggered by leaf water deficit, but by the root's response to the salinity. The flux of ABA in the xylem sap of the three species was more than enough to account for the amount of ABA in leaves, in the presence and absence of salinity. This suggests that the roots may be the source of at least part of the ABA found in leaves.

Response to terminal water deficit stress of cowpea, pigeonpea, and soybean in pure stand and in competition

2008 ◽  
Vol 59 (1) ◽  
pp. 27 ◽  
Author(s):  
A. A. Likoswe ◽  
R. J. Lawn
Keyword(s):  
Water Deficit ◽  
Water Status ◽  
Leaf Water ◽  
Water Deficit Stress ◽  
Pure Stand ◽  
Leaf Water Status ◽  
Test Species ◽  
Dehydration Tolerance ◽  
Dehydration Avoidance ◽  
Leaf Survival

The response to terminal water deficit stress of three grain legumes, soybean, cowpea and pigeonpea, was evaluated in plants grown in large tubes, in competition with either the same species or one of the other two species. The aim was to explore how species differences in drought response affected water use, growth and survival of plants in pure stand and in competition. Two plants, comprising the test species and its competitor, were grown in each tube. Water was withheld 26 days after sowing by which time each plant had at least three fully expanded trifoliolate leaves. Leaf water status and plant growth were measured through destructive samples when 80% and 90% of the estimated plant available water (PAW) was depleted and at plant death, while PAW depletion, node growth and leaf survival were monitored at 2–3 day intervals until the last plants died (61 days after water was withheld). In pure stand, the rate of PAW depletion was initially slowest in cowpea despite its much larger leaf area, and fastest in soybean. Node growth was most sensitive in cowpea, ceasing at 65% PAW depletion compared with 85% PAW depletion in pigeonpea and soybean, so that the latter two species produced relatively more nodes after water was withheld. However, senescence of the lower leaves was most rapid in soybean and slowest in cowpea. Cowpea and pigeonpea extracted almost all PAW and died an average 18 days and 14 days, respectively, after maximum PAW depletion. In contrast, soybean died before 90% of PAW was depleted and so in pure stand used less water. There were otherwise only minor differences between the species combinations in the timing and maximum level of PAW depletion. The ability of cowpea and pigeonpea to maintain leaf water status above lethal levels for longer was achieved through different means. Cowpea relied primarily on dehydration avoidance and maintained tissue water status higher for longer, whereas pigeonpea demonstrated greater dehydration tolerance. While significant levels of osmotic adjustment (OA) were identified in soybean and pigeonpea, OA appeared to be of limited benefit to leaf survival in soybean. Pigeonpea invested significantly more total dry matter (TDM) in roots than either cowpea or soybean. Cowpea survived longest in pure stand whereas pigeonpea and soybean survived shortest in pure stand, suggesting that the dehydration avoidance response of cowpea was more effective in competition with like plants whereas the dehydration tolerance strategies of pigeonpea and soybean were least effective when competing against like plants. On average, TDM per plant ranked in the order cowpea > soybean > pigeonpea, largely reflecting initial differences in plant size when water was withheld. However, there was an inverse relation between TDM of a species and that of its competitor, so that in effect, water not used by a given plant to produce TDM was used by its competitor and there were no differences in TDM production per tube.

scholarly journals Foliar water‐uptake strategies are related to leaf water status and gas exchange in plants from a ferruginous rupestrian field

2019 ◽  
Vol 106 (7) ◽  
pp. 935-942 ◽  
Author(s):  
Daniela Boanares ◽  
Alessandra R. Kozovits ◽  
José P. Lemos‐Filho ◽  
Rosy M. S. Isaias ◽  
Ricardo R. R. Solar ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Water Uptake ◽  
Water Status ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Foliar Water Uptake

scholarly journals Leaf water relations in epiphytic ferns are driven by drought avoidance rather than tolerance mechanisms

2021 ◽  
Author(s):  
Courtney Campany ◽  
Jarmila Pittermann ◽  
Alex Baer ◽  
Helen Holmlund ◽  
Eric Schuettpelz ◽  
...  
Keyword(s):  
Stomatal Density ◽  
Water Status ◽  
Costa Rican ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Trait Divergence ◽  
Drought Avoidance ◽  
Fern Species ◽  
Selection For

Opportunistic diversification has allowed ferns to radiate into epiphytic niches in angiosperm dominated landscapes. However, our understanding of how ecophysiological function allowed establishment in the canopy and the potential transitionary role of the hemi-epiphytic life form remain unclear. Here, we surveyed 39 fern species in Costa Rican tropical forests to explore epiphytic trait divergence in a phylogenetic context. We examined leaf responses to water deficits in terrestrial, hemi-epiphytic, and epiphytic ferns and related these findings to functional traits that regulate leaf water status. Epiphytic ferns had reduced xylem area (-63%), shorter stipe lengths (-56%), thicker laminae (+41%), and reduced stomatal density (-46%) compared to terrestrial ferns. Epiphytic ferns exhibited similar turgor loss points, higher osmotic potential at saturation, and lower tissue capacitance after turgor loss than terrestrial ferns. Overall, hemi-epiphytic ferns exhibited traits that share characteristics of both terrestrial and epiphytic species. Our findings clearly demonstrate the prevalence of water conservatism in both epiphytic and hemi-epiphytic ferns, via selection for anatomical and structural traits that avoid leaf water stress. Even with likely canalized physiological function, adaptations for drought avoidance have allowed epiphytic ferns to successfully endure the stresses of the canopy habitat.

Comparison of different uni- and multi-variate techniques for monitoring leaf water status as an indicator of water-deficit stress in wheat through spectroscopy

2017 ◽  
Vol 160 ◽  
pp. 69-83 ◽  
Author(s):  
Bappa Das ◽  
Rabi N. Sahoo ◽  
Sourabh Pargal ◽  
Gopal Krishna ◽  
Rakesh Verma ◽  
...  
Keyword(s):  
Water Deficit ◽  
Water Status ◽  
Leaf Water ◽  
Water Deficit Stress ◽  
Leaf Water Status

scholarly journals The Role of Bundle Sheath Extensions and Life Form in Stomatal Responses to Leaf Water Status

2011 ◽  
Vol 156 (2) ◽  
pp. 962-973 ◽  
Author(s):  
Thomas N. Buckley ◽  
Lawren Sack ◽  
Matthew E. Gilbert
Keyword(s):  
Life Form ◽  
Water Status ◽  
Bundle Sheath ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Stomatal Responses

Water relations and gas exchange in young coconut palm (Cocos nucifera L.) as influenced by water deficit

1997 ◽  
Vol 75 (1) ◽  
pp. 18-27 ◽  
Author(s):  
Anne Repellin ◽  
Serge Braconnier ◽  
Daniel Laffray ◽  
Claude Daniel ◽  
Yasmine Zuily-Fodil
Keyword(s):  
Water Vapor ◽  
Gas Exchange ◽  
Water Deficit ◽  
Drought Resistance ◽  
Water Status ◽  
Cocos Nucifera ◽  
Leaf Water ◽  
Coconut Palm ◽  
Leaf Water Status ◽  
Cocos Nucifera L

Drought is the main climatic limitation to coconut palm (Cocos nucifera L.) production. To identify early screening parameters for drought resistance, physiological responses to water deficit were investigated for the first time using containerized young plants grown outside. Three varieties were studied: 'West Coast Tall' (drought avoiding), 'Malayan Yellow Dwarf' (drought susceptible), and their progeny, the hybrid 'PB 121' (drought resistant). Leaf water status (relative water content, leaf water potential) and leaf gas exchange parameters (stomatal conductance to water vapor, net photosynthetic rate, and leaf internal CO2 concentration) were measured throughout a drying cycle induced by withholding watering. On fully hydrated plants, the sensitivity of stomata to atmospheric water vapor deficit was also investigated. In the three varieties, stomatal conductance to water vapor declined before leaf water status parameters were affected. The existence of a root-to-shoot communication system was proposed. Net photosynthetic rate was highly dependent on stomatal aperture, but nonstomatal factors also participated in the reduction of CO2 fixation. Since gas exchange rates were equally sensitive to drought in the three varieties, they could not be used as screening parameters for drought resistance. Under severe drought stress, both relative water content and leaf water potential differed significantly among populations. 'West Coast Tall' maintained a higher leaf water status than 'Malayan Yellow Dwarf'. Remarkably, the water status parameters of 'PB 121' were intermediate between those of the two parents. Similar ranking was obtained in experiments with excised leaflets. The high reproductibility of the results suggests that leaf water status parameters might be useful as early selection criteria for drought resistance in coconut palm. Key words: Cocos nucifera L., gas exchange, leaf water status parameters, water deficit, water relations.

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