Comparisons of physiological and anatomical characteristics between two cultivars in bi-leader apple trees ( Malus  ×  domestica Borkh.) 1 1Abbreviations: Chl, chlorophyll; DABB, days after bud break; Gs, stomatal conductance; Ψleaf, leaf water potential; ΨMD, midday leaf water potential; ΨPD, pre-dawn leaf water potential; LEC, lower epidermis cell; PPFD, photosynthetic photon flux density; Pn, net photosynthesis rate; Sd, stomatal density; SLW, specific leaf weight; UEC, upper epidermis cell; Ve, vessel; VPD, vapor pressure deficit; Xr, xylem rays.

2018 ◽  
Vol 231 ◽  
pp. 73-81 ◽  
Author(s):  
Narayan Bhusal ◽  
Siddhi J. Bhusal ◽  
Tae-Myung Yoon
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Vapor Pressure Deficit ◽  
Stomatal Density ◽  
Net Photosynthesis ◽  
Photosynthetic Photon Flux Density ◽  
Leaf Water ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Epidermis Cell

scholarly journals Autonomy and network modulation of photosynthesis and water relations of Coffea arabica in the field

2008 ◽  
Vol 20 (2) ◽  
pp. 141-151 ◽  
Author(s):  
Lívia H.G. de Camargo-Bortolin ◽  
Carlos H.B. A. Prado ◽  
Gustavo M. Souza ◽  
Paula Novaes
Keyword(s):  
Coffea Arabica ◽  
Vapor Pressure Deficit ◽  
Leaf Gas Exchange ◽  
Principal Component ◽  
Net Photosynthesis ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Physiological Variables ◽  
Physiological Variability

The degree of connection between leaf gas exchange and leaf water potential, and the autonomy of these variables in relation to meteorological conditions were determined in three cultivars of Coffea arabica during clear and cloudy days. High values of vapor pressure deficit, air temperature and photosynthetic photon flux density resulted in low leaf autonomy during a clear day, irrespective the degree of connection among leaf physiological variables. Tight synchronization between physiological and meteorological variables was considered one important cause of net photosynthesis (P N) decreasing during a clear day. In contrast, diurnal P N was around three times higher on a cloudy day, when all cultivars presented high autonomy. Principal component analyses corroborated autonomy results revealing unambiguous opposition between leaf physiological and meteorological vectors, besides less leaf physiological variability throughout the clear day. Despite these general responses during clear and cloudy days, there were significant differences among studied cultivars. Leaf autonomy was an important reference to evaluate C. arabica under environmental stress and should be taken into account when selecting cultivars under field conditions.

Parthenium weed (Parthenium hysterophorus L.): gas exchange characteristics as a basis for prediction of its geographical distribution

1977 ◽  
Vol 28 (3) ◽  
pp. 449 ◽  
Author(s):  
D Doley
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Gas Phase ◽  
Leaf Water Potential ◽  
Dark Respiration ◽  
Leaf Water ◽  
Parthenium Hysterophorus ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Very High

Gas exchange studies in Parthenium hysterophorus L., a weed recently introduced into central Queensland, indicate that its limits of distribution may be very wide in the humid and subhumid regions of Australia. Under conditions of high leaf water potential, the maximum rate of apparent photosynthesis of cabinet-grown plants was 77 ng cm-2 sec-1, with a temperature optimum of 28°C. Gas phase diffusive resistances were very low and insensitive to photosynthetic photon flux density at high water potentials (–5.0 bars), but became greater and quite sensitive to photon flux as the leaf water potential approached –20 bars. At temperatures between 10 and 40°C, transpiration increased slightly, and the dark respiration rate was almost constant, owing to a steady and considerable increase in gas phase diffusive resistance with temperature. The control of gas exchange broke down at about 42°C, so that transpiration in the light and dark proceeded at equal rates, and dark respiration rates were very high. Gas exchange in P. hysterophorus appears to be no more sensitive to reduced water potential than it is in several favoured crop and pasture species, but the distribution of this weed may be limited by even brief exposure to very high temperatures, or by prolonged drought.

Water Relations and Leaf Structure of the Evergreen Shrubs Eurya emarginata (Theaceae) and E. japonica in Coastal and Inland Habitats

1998 ◽  
Vol 46 (1) ◽  
pp. 135 ◽  
Author(s):  
Masako Mishio ◽  
Naoki Kachi
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Unit Area ◽  
Leaf Water ◽  
Photon Flux ◽  
Leaf Water Content ◽  
Shrub Species ◽  
Eurya Emarginata

Stomatal conductance and leaf water potential at around noon, pre-dawn leaf water potential, pressure–volume parameters, and leaf structural characteristics including leaf thickness, leaf dry mass per unit area and turgid leaf water content per unit area were compared between a coastal shrub species, Eurya emarginata (Thunb.) Makino and an inland shrub species, E. japonica Thunb. The pre-dawn leaf water potential was only slightly lower in E. emarginata than in E. japonica, and the environmental conditions such as the photosynthetic photon flux density and the vapour pressure deficit did not differ obviously between the two habitats. No apparent differences were observed in the pressure–volume parameters between the two species. On the other hand, E. emarginata had much higher stomatal conductance and significantly thicker leaves with higher turgid leaf water content per unit area than E. japonica. The thicker leaf with higher water content on an area basis in E. emarginata maintains adequate leaf turgor pressure against a higher rate of transpiration.

Stomatal conductance and stomatal behavior in Populus clones and hybrids

1988 ◽  
Vol 66 (7) ◽  
pp. 1404-1414 ◽  
Author(s):  
R. Ceulemans ◽  
I. Impens ◽  
R. Imler
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Solar Irradiance ◽  
Columbia River ◽  
Growth Increment ◽  
Leaf Water ◽  
Photon Flux ◽  
Leaf Life Span ◽  
Stomatal Behavior ◽  
Late Autumn

Responses of abaxial, adaxial, and total leaf conductance to incident photosynthetic photon flux density, solar irradiance, and changing leaf water potential, as well as diurnal and seasonal patterns of stomatal conductances, were examined under field conditions for six Populus clones. Clones belonged to the species P. trichocarpa and to different interspecific crossings including P. deltoides, P. nigra, and P. maximowiczii. Black Cottonwood clone Columbia River showed stomatal behavior different from other clones in many aspects: (i) it was the only clone with hypostomatous leaves; (ii) its stomata remained open for a longer period of time, both diurnally and seasonally; (iii) the hysteresis effect in stomatal response to solar irradiance during the day was less pronounced; and (iv) its stomata showed hardly any response to declining leaf water potential. Leaf area duration and seasonal stomatal activity showed considerable clonal differences, which are in agreement with girth growth increment patterns. Clone Columbia River showed a much longer leaf life-span with considerable stomatal activity near late autumn, which might explain the substantial late-autumn girth growth increment of this clone.

scholarly journals Growth, photosynthesis and leaf water potential in young plants of Copaifera langsdorffii Desf. (Caesalpiniaceae) under contrasting irradiances

2009 ◽  
Vol 21 (3) ◽  
pp. 197-208 ◽  
Author(s):  
Carlos Cesar Ronquim ◽  
Carlos Henrique B. A. Prado ◽  
João Paulo de Souza
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Photochemical Efficiency ◽  
Net Photosynthesis ◽  
Leaf Water ◽  
Total Biomass ◽  
Natural Conditions ◽  
Significant Difference ◽  
Copaifera Langsdorffii

Growth and leaf nutrient content were compared in young potted plants of Copaifera langsdorffii in sunny and shaded areas without water stress. Besides, carbon assimilation and leaf water relations were evaluated by net photosynthesis, potential photochemical efficiency and leaf water potential during daily courses in dry and rainy periods under natural conditions in both contrasting irradiances. Higher values of total biomass, height and leaf area occurred in sunny than in shaded area. On the other hand, all young plants survived in shade under natural water stress probably by reason of fast and intense biomass accumulation in favor of roots in early development. There was no significant difference about nutrient concentration in leaves between plants growing in sunny and shaded areas. Net photosynthesis in shade increased occasionally when bunches of direct light reached the leaves. Theses sunflecks took place more frequently and at high intensity in dry period but they were more effective for net photosynthesis in rainy period. The ability of young plants to persist under natural conditions in contrasting irradiance up to 1,230 days after sowing could explain the wide distribution of C. langsdorffii in Cerrado physiognomies and in different types of forest.

Effect of Water Deficit on Carbon Dioxide Exchange and Leaf Elongation Rate of Panicum maximum Var. trichoglume

1976 ◽  
Vol 3 (3) ◽  
pp. 401 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng
Keyword(s):  
Carbon Dioxide ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Net Photosynthesis ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Carbon Dioxide Exchange ◽  
Leaf Elongation ◽  
Water Deficits ◽  
Water Potentials

The responses of carbon dioxide exchange and leaf elongation of potted P. maximum var. trichoglume plants to water deficits were investigated in controlled environments and outdoors during drying cycles down to -92 bars leaf water potential, The sensitivities of net photosynthesis and leaf elongation to water deficits were similar. The leaf water potentials at which net photosynthesis and elongation ceased (c. -12 bars), and stomatal resistance increased substantially (- 6 bars), were relatively unaffected by nitrogen supply, environmental conditions during growth, and whether plants had previously experienced stress. However, these factors influenced the rate of net photosynthesis, at high leaf water potentials by affecting stomatal resistance and at moderate water potentials by affecting both stomatal and intracellular resistances. Stomata1 resistance was more sensitive than intracellular resistance to water deficits. Dark respiration rate decreased with leaf water potential, and was higher in plants receiving additional nitrogen. At moderate leaf water potentials (-7 to -9 bars), net photosynthesis of this C4 grass exhibited light saturation and rates similar to C3 plants. We suggest that the difference in behaviour of controlled-environment-grown and field-grown plants to water deficits observed with some species is unlikely to be due to differences in the aerial environment, but may result from differences in the rate at which stress develops. The ecological significance and evolution of the C4 syndrome are discussed briefly.

Genotypic Variation in Light and Temperature Response of Photosynthesis in Nothofagus solandri Var. cliffortioides and N. menziesii

1996 ◽  
Vol 23 (4) ◽  
pp. 421 ◽  
Author(s):  
OJ Sun ◽  
GB Sweet
Keyword(s):  
New Zealand ◽  
Dark Respiration ◽  
Genotypic Variation ◽  
Temperature Response ◽  
Light Response ◽  
Net Photosynthesis ◽  
Photosynthetic Photon Flux Density ◽  
Ecosystem Dynamics ◽  
Photon Flux ◽  
Photon Flux Density

Responses of photosynthesis to light and temperature were studied in two Nothofagus species native to New Zealand: N. solandri var. cliffortioides (Hook. f.) Poole and N. menziesii (Hook. f.) Oerst.. Measurements of leaf photosynthesis were made in a controlled environment growth chamber at photosynthetic photon flux density between 0 and 700 μmol m-2 s-1 with temperatures set for 10, 20 and 25�C, on seedlings previously grown in a glasshouse from seed of three different origins. In both species, pronounced intraspecific variation was shown in dark respiration, light compensation point and light-saturated net photosynthesis (Amax). Seedlings of N. solandri showed higher dark respiration and light compensation levels than N. menziesii seedlings, but the two species did not differ in Amax. Change in temperature resulted in significant change in the response of photosynthesis to light in both N. solandri and N. menziesii. The differences between N. solandri and N. menziesii in light response of photosynthesis are discussed in terms of ecosystem dynamics of Nothofagus forests in New Zealand.

Vertical Wilting and Photosynthesis, Transpiration, and Water Use Efficiency of Sunflower Leaves

1979 ◽  
Vol 6 (1) ◽  
pp. 109 ◽  
Author(s):  
HM Rawson
Keyword(s):  
Water Use Efficiency ◽  
Water Potential ◽  
Water Use ◽  
Leaf Water Potential ◽  
Stomatal Closure ◽  
Net Photosynthesis ◽  
Leaf Water ◽  
Vertical Orientation ◽  
Use Efficiency ◽  
Node Position

Plants of two sunflower cultivars were exposed to a number of soil drying cycles and the gas exchange of young, fully expanded leaves at different nodes was measured continuously from when the leaves were turgid until when they were severely and vertically wilted. Peak rates of net photosynthesis increased with the height of leaf insertion but, regardless of node position, leaves at vertical wilting always had rates of net photosynthesis which were close to 50% of peak rates. Although the leaf water potential at which vertical wilting occurred ranged between - 1.3 and -2.2 MPa and varied even for a particular leaf position, there was a similar relationship between the rate of reduction in photosynthesis and the reduction in leaf water potential. No evidence was found for a threshold leaf water potential at which stomatal closure occurs. Water use efficiency improved when leaves changed from a horizontal to a vertical orientation, apparently through changes in leaf temperature but. by the stage of wilting, water use efficiency had already markedly improved over efficiencies of turgid leaves. Much of this improvement stemmed from changes in leaf conductances. No clear differences between cultivars were evident in any parameter measured. The likely effects that wilting will have on water use efficiency in the field and strategies for optimising water use on a diurnal basis are discussed.

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