Transpirational, Leaf Area, Stomatal and Photosynthetic Responses to Gradually Induced Water Stress in Four Temperate Herbage Species

1978 ◽  
Vol 5 (2) ◽  
pp. 113 ◽  
Author(s):  
GG Johns

A series of physiological parameters was monitored under glasshouse conditions on micro-swards of four temperate herbage species. The micro-swards were grown on large soil cores so that the slow onset of water stress usually encountered in the field was simulated when water was withheld. Generally, water use per unit cover continued at a high rate even when water stress was causing considerable leaf death. Leaf diffusive conductance fell only gradually and did not reach minimum values until after much of herbage on the swards was dead. Stomatal closure in all species reduced water use per unit foliage cover by only 20-30%. Under increasing water stress, gross photosynthesis resembled stomatal conductances in remaining substantial (>50% of controls) even when relative water contents had fallen to below 80%. Both water use and gross photosynthesis were reduced more as a result of the reduced leaf area available for gaseous exchange than by the influence of stomatal action. Leaf moisture retention curves were similar for all species, there being a loss of c. 10% of relative water content per unit leaf water potential, down to drier than -5 MPa. It was concluded that the generally inferior herbage yields of white clover under dryland field conditions could be due in part to its relatively high leaf diffusive conductances when under water stress, while the better than average tall fescue yields under similar conditions may be attributed in part to its ability to roll its leaves tightly when water stress prevails.

1982 ◽  
Vol 12 (4) ◽  
pp. 725-730 ◽  
Author(s):  
T. J. Dean ◽  
S. G. Pallardy ◽  
G. S. Cox

Photosynthetic characteristics and morphology of leaves of black walnut (Juglansnigra L.) seedlings grown under different types and degrees of shade were investigated by measuring insitu gross photosynthesis (Ps) and by microscopic study of leaf material. During the growing season of 1979, seedlings were subjected to artificial shading of two types: the first type simulated two overstory densities (leaf-area indices of 1 and 2) with corresponding proportions of sunflecks and total transmission of 50 and 21%, respectively, of incident photosynthetically active radiation (PAR, 400–700 nm); the second consisted of two densities of greenhouse shading screen which transmitted approximately 16 and 3% of incident PAR. From quantum efficiency values derived from Ps – quantum flux density response curves it was determined that the walnut seedlings adjusted photosynthetically to shade. Quantum efficiency increased as much as 44% with the densest shading. Light-saturated Ps did not appear to decline with increased shading if sunflecks were present, and it declined only 18% under complete shade that transmitted about 16% of incident PAR. Estimated daily photosynthesis per unit leaf area for black walnut growing under heavy and complete shade (3% of incident PAR) was nearly one-half that of the unshaded control. Shading resulted in plants that possessed leaves that were thinner, had less palisade mesophyll, had lower stomatal density, and had more chlorophyll per unit of leaf area. These data indicate that black walnut seedlings have the capacity for substantial photosynthesis under shade and may be more shade tolerant than silvicultural classifications suggest.


1999 ◽  
Vol 3 (1) ◽  
pp. 55-69 ◽  
Author(s):  
B. Kruijt ◽  
C. Barton ◽  
A. Rey ◽  
P. G. Jarvis

Abstract. The 3-dimensional forest model MAESTRO was used to simulate daily and annual photosynthesis and transpiration fluxes of forest stands and the sensitivity of these fluxes to potential changes in atmospheric CO2 concentration ([CO2]), temperature, water stress and phenology. The effects of possible feed-backs from increased leaf area and limitations to leaf nutrition were simulated by imposing changes in leaf area and nitrogen content. Two different tree species were considered: Picea sitchensis (Bong.) Carr., a conifer with long needle longevity and large leaf area, and Betula pendula Roth., a broad-leaved deciduous species with an open canopy and small leaf area. Canopy photosynthetic production in trees was predicted to increase with atmospheric [CO2] and length of the growing season and to decrease with increased water stress. Associated increases in leaf area increased production further only in the B. pendula canopy, where the original leaf area was relatively small. Assumed limitations in N uptake affected B. pendula more than P. sitchensis. The effect of increased temperature was shown to depend on leaf area and nitrogen content. The different sensitivities of the two species were related to their very different canopy structure. Increased [CO2] reduced transpiration, but larger leaf area, early leaf growth, and higher temperature all led to increased water use. These effects were limited by feedbacks from soil water stress. The simulations suggest that, with the projected climate change, there is some increase in stand annual `water use efficiency', but the actual water losses to the atmosphere may not always decrease.


2006 ◽  
Vol 24 (3) ◽  
pp. 160-165 ◽  
Author(s):  
G. Niu ◽  
D.S. Rodriguez ◽  
R. Cabrera ◽  
C. McKenney ◽  
W. Mackay

Abstract The water use and crop coefficient of five woody landscape species were determined by growing the shrubs both in 56-liter (15 gal) drainage lysimeters and in above-ground 10-liter containers (#3). Water use per plant, crop coefficient and overall growth parameters differed by species and culture system. Of the five species tested, Buddleia davidii ‘Burgundy’ and Nerium oleander ‘Hardy Pink’ had higher water use per plant in the lysimeters than in the containers. Water use per plant for Abelia grandiflora ‘Edward Goucher’, Euonymus japonica and Ilex vomitoria ‘Pride of Houston’ was the same for the two culture systems. Crop coefficient and growth index of A. grandiflora, E. japonica, and I. vomitoria was similar between the two systems. The growth index of B. davidii and N. oleander was much higher in the lysimeters than in the containers. Abelia grandiflora and E. japonica had more growth in the containers than in the lysimeters while I. vomitoria had slightly larger leaf area in the lysimeters than in the containers. The culture system did not affect the water use per unit leaf area of all species. Therefore, our results indicated that by quantifying the leaf area, the plant water use in the two culture systems is exchangeable.


1974 ◽  
Vol 82 (2) ◽  
pp. 339-342 ◽  
Author(s):  
Ali T. Ayoub ◽  
H. M. Ishag

SummaryLeaf burn and gradual death were the characteristic symptoms of injury in P. vulgaris sown on a sodic soil. Plant growth, total leaf area per plant, number of stomata and epidermal cells per unit leaf area, and relative water content were drastically reduced in injured plants; these were associated with large sodium accumulation in the shoot resulting in cation imbalance.


1996 ◽  
Vol 23 (1) ◽  
pp. 63 ◽  
Author(s):  
AB Samarakoon ◽  
RM Gifford

Cotton (Gossypium hirsutum cv. Sicala 34) was grown at 352 ('low CO2') or 710 ('high CO2') μL L-1 atmospheric CO2 in continuously wet soil, or in drying soil, or in drying soil re-wetted after plant wilting. In wet soil, the approximately 15% reduction in transpiration per unit leaf area owing to high CO2 was only half that for other species, whereas effects on growth and leaf area were relatively larger. Consequently, water use per plant was 45-50% higher for high CO2 plants in contrast to other species for which the rate of water use is either the same or lower in high CO2. Greater plant water use early in a drying cycle caused the soil to dry faster under high CO2 than under low CO2. The addition of the consequential greater water stress at high CO2 in drying soil to the direct CO2 effect on stomata caused the transpiration rate of high CO2 plants to fall by up to 60% as the soil dried relative to plants drying at low CO2. After re-wetting the dry soil, the reduction in transpiration rate at high CO2 returned within hours to the value of 15% seen in wet soil. The results were inconsistent with the idea that water deficits increase the sensitivity of stomatal aperture to CO2. Other consequences of drier soil under high CO2 compared with low CO2 were: (a) unlike in many other species, in cotton, the relative growth enhancement by high CO2 is not higher under drying soil compared with wet soil owing to the opposite effect on soil water content; and (b) the increased water-use efficiency in drying soil relative to wet soil was greater in high CO2 plants than in low CO2. The confounding of indirect effects of soil water with the direct CO2 effects may explain the wide variability of literature reports about CO2 effects on stomatal conductance and water use.


1976 ◽  
Vol 54 (10) ◽  
pp. 1023-1034 ◽  
Author(s):  
William E. MacHardy ◽  
Lloyd V. Busch ◽  
Robert Hall

The relationship between the development of water stress and foliar symptom expression within chrysanthemum (Chrysanthemum morifolium Ramat) cuttings infected with Verticillium dahliae Kleb. was examined using relative water content (RWC), diffusive resistance to water vapor loss (stomatal resistance), and dye distribution along water-transport pathways as indicators of water stress. The RWC remained at a normal level until symptoms appeared, but stomatal resistance increased beginning about 8 days before symptoms. Dye movement along xylem elements was uniform within uninoculated checks and also within infected plants until stomatal resistances increased. Veinal dye distribution was incomplete within tissue exhibiting increased stomatal resistances, and the extent of dye interruption was closely aligned to the magnitude of resistance increase. Apparently, stomatal closure effectively prevented tissue desiccation under conditions of high, localized internal water stress, but this mechanism could not prevent tissue from becoming flaccid or wilted when water transport became so limited that water was deficient even within the large veins.


1983 ◽  
Vol 10 (1) ◽  
pp. 43 ◽  
Author(s):  
DW Turner ◽  
E Lahav

Bananas (cv. Williams) were grown for 12 weeks in sunlit growth chambers at day/night temperatures of 17/10, 21/14, 25/18, 29/22, 33/26 or 37/30°C. Humidity was not controlled. At 17/10°C, the plants showed chilling injury and heat injury occurred at 37/30°C. Total plant dry weight was greatest at 25/18°C while leaf area was greatest at 33/26°C. At high temperatures proportionately less dry matter was present in the roots and corm compared with plants at 25/18°C. High temperatures produced more horizontal leaves but, to compensate for this, the laminae folded more readily. Lamina folding was closely associated with relative water content of the laminae, except under cool conditions where laminae folded despite high (97-99%) leaf relative water contents. Unit leaf rate (increase in whole plant dry weight per unit leaf area per unit time) was greatest at 21/14°C (5.8 g m-2 day-1) and least at 37/30°C (1.7 g m-2 day-1.) and had a strong negative association with whole-plant leaf resistance. Leaf relative water content was more closely associated with vapour pressure deficit than temperature and even at 37/30°C was high at 94%.


Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 75
Author(s):  
Michele Faralli ◽  
Pier Lugi Bianchedi ◽  
Massimo Bertamini ◽  
Claudio Varotto

Understanding the physiological basis underlying the water stress responses in grapevine is becoming increasingly topical owing to the challenges that climate change will impose to grapevine agriculture. Here we used cv. Pinot gris (clone H1), grafted on a series of tolerant (1103Paulsen; P), sensitive (SO4) and recently selected (Georgikon28; G28, Georgikon121; G121, Zamor17; Z17) rootstocks. Plants were either subjected to reduced water availability (WS) or maintained at pot capacity (WW). Photosynthetic (light response curves), stomatal and in vivo gas exchange analysis were carried out as well as dynamics of daily water use (WU), leaf area accumulation with affordable RGB imaging pipelines and leaf water potential. Significant genotypic variation was recorded between rootstocks for most of the traits analyzed under optimal conditions with P and SO4 showing a more vigorous growth, higher CO2 assimilation rate, stomatal conductance and stomatal density per unit of leaf area than G28, G121, Z17 (p < 0.001). Under WS, rootstocks induced different water stress response in Pinot gris, with G28 and G121 showing a higher sensitivity of water use to reduced water availability (WS) (p = 0.021) and no variation for midday leaf water potential until severe WS. P, Z17 and to some extent SO4 induced a pronounced near-anisohydric response with a general WU maintenance followed by reduction in leaf water potential even at high levels of soil water content. In addition, G28 and G121 showed a less marked slope in the linear relationship between daily water use and VPD (p = 0.008) suggesting elevated sensitivity of transpiration to evaporative demand. This led to an insensitivity for total dry weight biomass of G28 and G121 under WS conditions (p < 0.001). This work provides: (i) an in-depth analysis for a series of preferable traits under WS in Pinot gris; (ii) a characterization of Pinot gris × rootstock interaction and a series of desirable traits under WS induced by several rootstocks; (iii) the potential benefit for the use a series of affordable methods (e.g., RGB imaging) to easily detect dynamic changes in biomass in grapevine and quickly phenotype genotypes with superior responses under WS. In conclusion, the near-isohydric and conservative behavior observed for G28 and G121 coupled with their low vigor suggest them as potential Pinot gris rootstock candidates for sustaining grapevine productivity in shallow soils likely to develop terminal stress conditions.


2020 ◽  
pp. 1-13
Author(s):  
Amandeep Kaur ◽  
Rashpal Singh Sarlach

Water stress is one of the major and challenging abiotic stress that affects the plant mostly at all stages like tillering, booting, anthesis, grain formation and grain filling. The aim of the present study is to investigate the effect of water stress on relative water content, leaf area and stay green habit of Iranian landraces along with commercial relevant checks under irrigated, restricted irrigation and rain-fed conditions. Iranian landraces were selected based on minimum reduction in vigor index as compared to control lines during preliminary screening experiment in the lab in which water stress is induced by Polyethylene glycol (PEG 6000). A field experiment was carried out at the experimental area of the Department of Plant Breeding & Genetics, Punjab Agricultural University, Ludhiana, Punjab during 2016-2017. The relative water content of Iranian landraces was calculated at the bolting stage according to the turgid weight by applying the equation of relative water content. Leaf area was recorded by leaf area meter and stay-green habit based on a 1-4 visual scale. Analysis of variance revealed interaction among treatment and genotypes was significant (P≤ 0.05) for the leaf area, relative water content, stay green habit at anthesis and 30 days after anthesis. Leaf area, relative water content and stay green habit of Iranian landraces along with commercial checks reduced under water stress conditions. Based on the performance of Iranian landraces under stress conditions, 5 lines IWA 8600397, IWA 8600567, 8606739, IWA 8606786 and IWA 8600753 were considered as water stress tolerant.


1980 ◽  
Vol 7 (5) ◽  
pp. 575 ◽  
Author(s):  
HM Rawson ◽  
GA Constable ◽  
GN Howe

In field studies of several cultivars of sunflower grown on stored soil moisture or with irrigation, yield was positively related to leaf area at anthesis. The regression which described this relationship stated that 1370 kg seed ha-1 were associated with a unit increment in leaf area index. Cultivars differed in final leaf number, rate of leaf appearance, and in the vertical distribution of leaf area in the profiles. Final leaf number of plants grown on stored moisture remained the same as in irrigated plants, but the period for which each leaf grew was reduced from 19 to 16 days while the average growth rate was reduced from 13 to 6 cm2 day-1. These changes reduced the final leaf area from 5700 to 1900 cm2 per plant. As water stress increased, the period when leaves grew fastest became progressively earlier, from approximately 35% Amax to when leaves were less than 5 cm2. Water stress increased stomatal frequencies but reduced the area of individual stomata so that the area of the stomatal apparatus per unit leaf area was unchanged. This may partially explain the constancy of peak gas exchange per unit leaf area of sunflower grown under different water regimes. There was evidence that leaves could recommence growth when the stress was alleviated.


Sign in / Sign up

Export Citation Format

Share Document