Water relations parameters on single leaves obtained in a pressure bomb and some ecological interpretations

Cheung, Y. N. S.; Tyree, Melvin T.; Dainty, J.

doi:10.1139/b75-162

Cited by 206 publications

(138 citation statements)

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“…It was observed that at any given water content, the flag leaf had a lower i than the lower leaves. This property offlag leaves can also be ascribed to the different cellular structure of the leaves since the cells with thicker cell walls, as postulated for the flag leaf, are expected to show a sharper decline in their 4P in response to a given change in water content than the cells with less rigid cell walls, as in the other leaves (6,16,28). Therefore, a flag leaf will reach lower values of water potential faster than the other leaves as the sun rises, and it would maintain this for the whole day although the water content would not decrease much.…”

Section: Discussionmentioning

confidence: 94%

Differences in Water Relations and Physiological Characteristics in Leaves of Wheat Associated with Leaf Position on the Plant

Aggarwal¹,

Sinha²

1984

Plant Physiol.

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The seasonal change in leaf water potential and its components, stomatal resistance, specific leaf weight, photosynthesis rate, the activities of ribulose-1,5-bisphosphate carboxylase and nitrate reductase, and soluble proteins were measured in flag leaves (ninth from base in position), seventh and fifth leaves of wheat Trticam aestipum L. cv Kalyansona. Flag leaves had a lower water and solute potential and lower or equal turgor pressure than seventh and fifth leaves. These differences were found to be independent of environment. The rate of photosynthesis and nitrate reductase activity were always lower in fifth and seventh leaves than in flag leaf. The photosynthetic efficiency in flag leaves appeared to be associated with lower stomatal resistance and higher specific leaf weight. The relations between leaf water potential and relative water content showed a change with leaf position. This change possibly allows flag leaf to maintain its functional efficiency despite its lower water potential.The physiological activity ofa leaf, particularly photosynthesis, depends on leaf age, genotype, and assimilate demand by sinks in addition to effects of environment (1 1, 23, 32). Leaf water status influences all aspects of growth and development (2,13,22). At t' of -1.0 to -1.5 MPa, most physiological processes such as leaf expansion, stomatal conductance, photosynthesis rate, and nitrogen metabolism are reduced (5, 13).In a recent study (Aggarwal et aL, unpublished), it was observed that the leaf 4' decreased to -2.0 MPa at flowering in irrigated wheat plants when dry matter production was at its peak and the flag leaf was most active (10, 25). A similar change in water relations at flowering has also been observed in sorghum (12, 24) and soybean (33). These studies also indicated that though leaf 4 was reduced at flowering, the physiological activity of the leaf was not impaired, rather it was improved. This observation contrasts with earlier studies showing sensitivity of physiological processes to small decreases in water potential (4, 13). It is, therefore, necessary to study the various physiological activities simultaneously with water relations at different growth stages.In the present investigation, seasonal changes in 4', 4',, and P have been studied concurrently with the Phs, the activities of RUBISCO and NR, r, and SLW in flag leaf and lower leaves of wheat. Pressure-volume curves were made to determine any change in water relations associated with the change in leaf position. An 15, 1980. Fertilizer at a rate of 75:60:60 kg/ha N:P:K was broadcast in the field prior to sowing. After germination, the distance between plants was maintained at 2.5 to 3.0 cm. In 20-d-old plants, main stems that were to be used subsequently for the measurements, were tagged. The field was irrigated as per agronomic practice at crown

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Section: Discussionmentioning

confidence: 94%

Differences in Water Relations and Physiological Characteristics in Leaves of Wheat Associated with Leaf Position on the Plant

Aggarwal¹,

Sinha²

1984

Plant Physiol.

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“…The results suggest that elevated CO2 increases the elasticity of tissues, thereby facilitating the maintenance of turgor over a greater change in water content and hence, water potential (Cheung, Tyree & Dainty, 1975), The greater elasticity of tissues might have facilitated grow^th of sugar maple under elevated CO3, as shown by the 10-fold increase in leaf area (Tschaplinski et al, 1995). A similar increase in elasticity of three herbaceous species, including Lotus corniculatus, S. minor, and P. media W'ith plants grown in elevated CO.^ was reported by .…”

Section: Drought and Co^ Effects On Osmotic Potential Of Leavesmentioning

confidence: 99%

“…For example, drought reduced the water saturation deficit of sugar maple (a drought avoidance response), whereas drought increased the water saturation deficit in sweetgum (a drought tolerance response). The increase in e^^^ of sycamore under drought is a drought avoidance response, where the decrease in tissue elasticity results in a greater decline in water potential and turgor pressure per unit water loss (Cheung et al, 1975).…”

Section: Drought and Co^ Effects On Osmotic Potential Of Leavesmentioning

confidence: 99%

Interactions between drought and elevated CO₂ on osmotic adjustment and solute concentrations of tree seedlings

1995

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SUMMARYAlthough drought tolerance of tree species is a critical determinant of forest composition, how elevated CO^ affects drought tolerance is uncertain. Interactions between elevated CO^ and drought on osmotic potential and osmotic adjustment of American sycamore (Platanus occidentalis L.), sweetgum {Liquidambar styractfiua L.), and sugar maple {Acer saccharum Marsh.) were investigated using 1-yr-old seedlings, planted in 8 1 pots and grown in four open-top chambers, containing either ambient air or ambient air enriched with 300 //mol moT' CO^. A weltwatered treatment with plants watered daily and a droughted treatment in which plants were subjected to a series of drought cycles were included within each chamber. Sugar maple and sweetgum seedlings completed a total of seven drying cycles, whereas sycamore seedlings, because of their greater leaf area and plant size, completed 11 cycles. The mean soil water potential at re-watering for droughted seedlings in ambient CO^ was -0-5, -0-7, and -1-8 MPa for sugar maple, sweetgum and sycamore, respectively, compared with -0'2, -0-7, and -12 MPa, respectively, under elevated CO^. By contrast, all well-watered plants were maintained at soil water potential >-01 MPa.Drought under ambient CO^ reduced osmotic potential at saturation for leaves of sycamore and sweetgum by 0-30 MPa and 0'61 MPa, respectively, but leaves of sugar maple did not display osmotic adjustment to drought. Elevated CO^ increased osmotic potential at turgor loss for leaves of sugar maple by 0-33 MPa under well-watered conditions, and 0-48 MPa under drought. This response was not evident in the other species and might be related to the rapid growth of sugar maple causing a depletion of solutes. Whereas drought reduced the total solute concentration in roots of sugar maple, primarily the result of a reduction in K, elevated CO^ did not alter the concentration of total solutes in roots of any of the three species. Elevated CO.^ has differing effects on drought tolerance among tree species, and thus might alter the competitive relations between species.

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“…From each pressure-volume curve, the following three parameters were calculated: the osmotic potential at saturation (Ψπfull), the osmotic potential at the turgor loss point (Ψπ0) and the modulus of elasticity (Emax - Cheung et al 1975, Jones & Turner 1980, Tyree & Jarvis 1982, Bowman & Roberts 1985. Twelve randomly chosen plants per treatment were analyzed (1 PV curve per plant; two plants per block).…”

Section: Pressure-volume Curves and Water Parameter Analysismentioning

confidence: 99%

The combined effects of Pseudomonas fluorescens CECT 844 and the black truffle co-inoculation on Pinus nigra seedlings

Núñez¹,

Medina²,

Berrocal-Lobo³

et al. 2015

iForest

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© iForest -Biogeosciences and Forestry IntroductionWater and nutrient availability are the main constraints on plant productivity in semi-arid Mediterranean ecosystems. The preservation of mycoflora diversity depends on the status of plant roots (Marulanda et al. 2006). Forest species in these areas often develop specific strategies to improve their water usage in response to drought (Martínez-Ferri et al. 2000).Several studies have been conducted to improve the quality of seedlings produced in nurseries (Caravaca et al. 2005). Several authors reported that soil amendment with ectomycorrhizal fungi and plant-growth-promoting rhizobacteria (PGPR) increased plant survival and seedling quality, especially in soils with low microbial activity (Chanway 1997, Probanza et al. 2001.Pseudomonas fluorescens generally shows several characteristics of an effective PGPR. It is easily cultivated in vitro, and it colonizes a wide range of ecological niches, including plant rhizospheres (Bolton et al. 1993). Additionally, P. fluorescens genomes are highly diverse, which most likely increases the P. fluorescens survival (Silby et al. 2009). The ecological flexibility of such bacteria allows them to exploit a wide variety of nutrients to adapt to environmental changes for survival. P. fluorescens also improves plant growth by producing phytohormones such as auxins (e.g., IAA -Karabaghli et al. 1998). It also has a high capacity for phosphorus solubilization and can produce siderophores (Matthijs et al. 2007). Despite the very well-known positive effects of P. fluorescens on plant survival, only a few studies have been conducted to study its influence on the growth of forest species (Rincón et al. 2008, Ouahmane et al. 2009). We recently demonstrated that the inoculation of Aleppo pine (Pinus halepensis Mill.) with P. fluorescens CECT 844 improved the vegetative growth and N absorption of the P. halepensis seedlings (Dominguez et al. 2012).The use of environmental-friendly natural microbial inocula, such as PGPR or mycorrhizal fungi, is presented in this study as a potential alternative fertilizers. These microorganisms are also beneficial for the maintenance of pre-existing soil microflora, thus contributing to the conservation of soil biodiversity. The amended soil in the nursey increases the vegetative vigor and morphophysiological quality of forest species growth for reforestation purposes (Chanway 1997).Information regarding the productivity of ectomycorrhizal fungi, their ecological functions and their contributions to the productivity and recovery of altered agroecosystems is increasingly valuable in agroforestry. In Spain, the black truffle (Tuber melanosporum Vitt.) is of substantial economic and social value in rural areas of the Mediterranean (Reyna 2007), although studies on the contributions of T. melanosporum to the growth and physiology of forest plants are scarce (Domínguez-Nuñez 2002). Moreover, the ecological value of such symbiosis in the recovery of Mediterranean ecosystems has not been well characterized.The...

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Water relations parameters on single leaves obtained in a pressure bomb and some ecological interpretations

Cited by 206 publications

References 7 publications

Differences in Water Relations and Physiological Characteristics in Leaves of Wheat Associated with Leaf Position on the Plant

Differences in Water Relations and Physiological Characteristics in Leaves of Wheat Associated with Leaf Position on the Plant

Interactions between drought and elevated CO₂ on osmotic adjustment and solute concentrations of tree seedlings

The combined effects of Pseudomonas fluorescens CECT 844 and the black truffle co-inoculation on Pinus nigra seedlings

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Water relations parameters on single leaves obtained in a pressure bomb and some ecological interpretations

Cited by 206 publications

References 7 publications

Differences in Water Relations and Physiological Characteristics in Leaves of Wheat Associated with Leaf Position on the Plant

Differences in Water Relations and Physiological Characteristics in Leaves of Wheat Associated with Leaf Position on the Plant

Interactions between drought and elevated CO2 on osmotic adjustment and solute concentrations of tree seedlings

The combined effects of Pseudomonas fluorescens CECT 844 and the black truffle co-inoculation on Pinus nigra seedlings

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Interactions between drought and elevated CO₂ on osmotic adjustment and solute concentrations of tree seedlings