Seasonal and diurnal variation in the stomatal conductance and paraheliotropism of tedera (Bituminaria bituminosa var. albomarginata) in the field

2013 ◽  
Vol 40 (7) ◽  
pp. 719 ◽  
Author(s):  
Kevin Foster ◽  
Megan H. Ryan ◽  
Daniel Real ◽  
Padmaja Ramankutty ◽  
Hans Lambers
Keyword(s):  
Stomatal Conductance ◽  
Drought Resistance ◽  
Water Loss ◽  
Incident Light ◽  
Leaf Water ◽  
Leaf Angle ◽  
Leaf Water Content ◽  
Bituminaria Bituminosa ◽  
Pasture Plant ◽  
Perennial Legumes

The mechanisms of drought resistance in perennial legumes are poorly understood. We explored the diurnal and seasonal variation (May, August, February) in stomatal conductance (gs) and paraheliotropism of three tedera accessions (Bituminaria bituminosa (L.) C.H. Stirton var. albomarginata) and lucerne (Medicago sativa L.), both perennial legumes, grown in the field. For the tedera accessions, there was a significant reduction in gs during the day in May (late autumn) and February (summer), but there was little reduction for lucerne. The peak leaf angle in the tedera accessions ranged from <40° to 70°, whereas for lucerne, the leaf angle was nearly parallel to incident light at 85°. Leaf water-use efficiency, relative leaf water content and leaf retention were higher for the tedera accessions than for lucerne in February. These results highlight the superior drought resistance of tedera compared with lucerne. The reduction in gs over the day in tedera shows the capacity of this species to reduce water loss quickly when conditions for CO2 fixation relative to water loss are highly unfavourable. The high retention of leaves in summer by tedera is a valuable trait for a perennial pasture plant in Mediterranean environments. Leaf folding, combined with effective stomatal control in summer, provides tedera with a set of physiological responses that confer high drought resistance.

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.

EXCISED-LEAF WATER RETENTION CAPABILITY AS AN INDICATOR OF DROUGHT RESISTANCE OF Triticum GENOTYPES

1982 ◽  
Vol 62 (3) ◽  
pp. 571-578 ◽  
Author(s):  
JOHN M. CLARKE ◽  
THOMAS N. McCAIG
Keyword(s):  
Triticum Aestivum ◽  
Drought Resistance ◽  
Water Retention ◽  
Significant Positive Correlation ◽  
Flag Leaf ◽  
Data Entry ◽  
Growing Season ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Large Numbers

Excised-leaf water retention was studied in 25 Triticum aestivum and 16 T. turgidum var. durum genotypes, as well as in 52 lines from a cross of high- and low-retention durums. A system of tared dishes, carrier trays and a data entry device interfaced with an electronic balance was used to facilitate handling large numbers of samples. At each sampling, four of the newest fully expanded leaves were taken from each plot, weighed, and then re weighed at intervals after standing in a control led-environment room and after oven drying. Weighing of leaves 24 h after excision resulted in poor separation of genotypes, particularly late in the season. A 6- to 10-h interval improved differentiation between genotypes. Initial leaf water content tended to decline over the growing season, while the amount of water lost in 24 h tended to remain relatively constant. In the hexaploid cultivars Columbus lost water slowest, while NB112 lost water fastest; in the durums, Pelissier was slowest, Hercules was fastest. Fifty-two lines from a Hercules × Pelissier cross exhibited a range of retention capabilites between the parental values. There was a low-order, but significant, positive correlation between yield and flag-leaf water retention in this material.

scholarly journals Physiological Effects of Drought Stress on Two Commercial Cultivars of the American Cranberry (Vaccinium macrocarpon)

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 772A-772
Author(s):  
Ricardo Cesped-Ruiz* ◽  
Bingru Huang
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Water Content ◽  
Air Temperature ◽  
Photosynthetic Rate ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Psii Efficiency ◽  
American Cranberry ◽  
Effects Of Drought

The American cranberry often undergoes drought stress during the summer. However, the physiological response of this species to drought is not well understood. This study was designed to determine the effects of drought on two commercial cranberry cultivars of high potential yield, `Ben Lear' and `Stevens', during a vegetative stage. The plants were subjected to drought for 15 days in a greenhouse. Soil water content, leaf water content, leaf photosynthetic rate, stomatal conductance, transpiration, differential leaf-air temperature, photochemical efficiency (Fv'/Fm') and the actual PSII efficiency (deltaF/Fm') decreased in those plants subjected to drought. Drought reduced differential leaf-air temperature at day 6 of treatment and stomatal conductance and transpiration starting at day 9 and photosynthetic rate at day 13. Drought decreased leaf water content at day 14 and Fv'/Fm' and PSII efficiency at day 15. Our results indicated that cranberry plants in vegetative stage were sensitive to drought for both cultivars and stomatal conductance was the most sensitive parameter among those examined for both cultivars.

scholarly journals Paraheliotropic Leaf Movement of Bush Bean in Response to Water Availability and Air Temperature

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 798D-798
Author(s):  
M. Raeini-Sarjaz ◽  
N.N. Barthakur
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Air Temperature ◽  
Leaf Water Potential ◽  
Water Availability ◽  
Leaf Water ◽  
Leaf Angle ◽  
Bush Bean ◽  
Leaf Movements ◽  
Positive Correlations

Paraheliotropic leaf movements of bush bean were studied in relation to water availability, ambient temperature, leaf water potential, and stomatal conductance in a growth chamber. Unifoliate leaf angle from the horizontal (LA), stomatal conductance (G), and leaf water potential (WP) were measured at noon to minimize the effect of leaf movements due to circadian rhythm. Photoperiod and light intensity on the foliage were kept constant at 14 h, and 200 μmol·m–2·s–1, respectively, throughout the measurements. Negative correlations were obtained between water availability (WA) and LA (R = –0.93), and WP and LA (R = –0.85), whereas positive correlations were shown between WA and WP (R = 0.90), WA and G (R = 0.90), and WP and G (0.84) at 35C air temperature. Similar correlations were observed at 25C between WA and LA (R = –0.91), WP and LA (R = –0.79), WA and WP (R = 0.91), WA and G (R = 0.68), and WP and G (R = 0.76). Air temperature significantly (P ≤ 0.01) affected leaf movements.

scholarly journals Where in the leaf is intercellular CO2 (Ci)? Considerations and recommendations for assessing gaseous diffusion in leaves

2020 ◽  
Author(s):  
Joseph R. Stinziano ◽  
Jun Tominaga ◽  
David T. Hanson
Keyword(s):  
Water Vapor ◽  
High Temperature ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Loss ◽  
Leaf Water ◽  
Marginal Effect ◽  
Photosynthetic Gas Exchange ◽  
Gaseous Diffusion ◽  
Intercellular Co2

AbstractThe assumptions that water vapor exchange occurs exclusively through stomata, that the intercellular airspace is fully saturated with water vapor, and that CO2 gradients are negligible between stomata and the intercellular airspace have enabled significant advancements in photosynthetic gas exchange research for nearly 60 years via calculation of intercellular CO2 (Ci). However, available evidence suggests that these assumptions may be overused. Here we review the literature surrounding evidence for and against the assumptions made by Moss & Rawlins (1963). We reinterpret data from the literature by propagating different rates of cuticular water loss, CO2 gradients, and unsaturation through the data. We find that in general, when cuticle conductance is less than 1% of stomatal conductance, the assumption that water vapor exchange occurs exclusively through stomata has a marginal effect on gas exchange calculations, but this is not true when cuticle conductance exceeds 5% of stomatal conductance. Our analyses further suggest that CO2 and water vapor gradients have stronger impacts at higher stomatal conductance, while cuticle conductance has a greater impact at lower stomatal conductance. Therefore, we recommend directly measuring Ci whenever possible, measuring apoplastic water potentials to estimate humidity inside the leaf, and exercising caution when interpreting data under conditions of high temperature and/or low stomatal conductance, and when a species is known to have high cuticular conductance.HighlightLeaf water vapor and CO2 exchange have been successfully used to model photosynthetic biochemistry. We review critical assumptions in these models and make recommendations about which need to be re-assessed.

scholarly journals Influence of Irradiance on Leaf Physiology and Plant Growth Characteristics of Rhododendron × `Pink Ruffles'

1991 ◽  
Vol 116 (5) ◽  
pp. 881-887 ◽  
Author(s):  
P.C. Andersen ◽  
J.G. Norcini ◽  
G.W. Knox
Keyword(s):  
Stomatal Conductance ◽  
Plant Growth ◽  
Chlorophyll Concentration ◽  
Dry Weight ◽  
Light Level ◽  
Leaf Water ◽  
Light Transmittance ◽  
Photon Flux ◽  
Leaf Water Content ◽  
Leaf Physiology

Leaf physiology and plant growth of Rhododendron × `Pink Ruffles' were compared under conditions of 100% sun and under polyethylene shadecloth with specifications of 69%, 47%, and 29% light transmittance. Net CO2 assimilation (A) and stomatal conductance to water vapor (gs) were often reduced for plants in the 100% sun regime, although few differences existed among the 69%, 47%, and 29% sun treatments. Stomatal conductance was very sensitive to leaf to air vapor pressure deficits (VPD), as evidenced by an 85% increase in gs with a decrease in VPD from 3.2 to 2.2 kPa. Light response curves established for plants after 54 days of exposure to 100% and 29% sun were similar, although A was consistently higher at all levels of photosynthetic photon flux for plants in the 29% sun regime. Maximum A was ≈5 and 6 μmol·m-2·s-1 for 100% and 29% sun-grown plants, respectively; light saturation occurred at ≈ 800 μmol·m-2·s-1 Midday relative leaf water content and leaf water potential were not affected by sun regime. The plant growth index decreased with increasing light level. Leaf, stem, and root dry weights; total leaf number and dry weight; total and individual leaf area; dry weight per leaf; and leaf chlorophyll concentration were reduced in 100% sun, yet few differences existed among the 69%, 47%, and 29% sun treatments. Shoot: root ratio and specific leaf weight were proportional to light level. Plants grown in the 100% sun regime were chlorotic and dwarfed, and plants in 29% sun were not sufficiently compact. One year after transplanting to the field under 100% sun, plants of all treatments were chlorotic and failed to grow.

Development of a diurnal dehydration index for spring barley phenotyping

2014 ◽  
Vol 41 (12) ◽  
pp. 1249 ◽  
Author(s):  
Pablo Rischbeck ◽  
Peter Baresel ◽  
Salah Elsayed ◽  
Bodo Mistele ◽  
Urs Schmidhalter
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Water Content ◽  
Water Status ◽  
Spring Barley ◽  
Leaf Water ◽  
Leaf Angle ◽  
Leaf Water Content ◽  
Diurnal Changes ◽  
Angle Distribution

Spectral and thermal assessments may enable the precise, high-throughput and low-cost characterisation of traits linked to drought tolerance. However, spectral and thermal measurements of the canopy water status are influenced by the crops’ soil coverage, the size of the biomass and other properties such as the leaf angle distribution. The aim of this study was to develop a referenced spectral method that would be minimally influenced by potentially perturbing factors for retrieving the water status of differing cultivars. Sixteen spring barley cultivars were grown in field trials under imposed drought stress, natural drought stress and irrigated conditions. The relative leaf water content of barley plants declines diurnally from pre-dawn until the afternoon, and other plant traits such as the biomass change little throughout the day. As an indicator of the current drought stress, pre-dawn and afternoon values of the relative leaf water content were assessed spectrally. Diurnal changes in reflectance are only slightly influenced by other perturbing factors. A new spectral index (diurnal dehydration index) was developed by using the wavelengths 730 and 457 nm collected from an active spectrometer. This index allowed the differentiation of the drought tolerance of barley plants. The diurnal dehydration index was significantly related to final biomass, grain yield and harvest index and significantly different between cultivars. Compared with other indices, the diurnal dehydration index offered a higher stability in retrieving the water status of barley plants. Due to its diurnal assessment, the index was barely influenced by the differences in cultivars biomass at the time of measurement. It may represent a valuable tool for assessing the water status or drought tolerance in breeding nurseries.

Sign in / Sign up

Export Citation Format

Share Document