Experiments and observations on the aftereffect of wilting on stomata of Rumex sanguineus

1970 ◽  
Vol 48 (3) ◽  
pp. 513-521 ◽  
Author(s):  
W. G. Allaway ◽  
T. A. Mansfield
Keyword(s):  
Carbon Dioxide ◽  
Water Stress ◽  
Water Content ◽  
Intercellular Space ◽  
Carbon Dioxide Concentration ◽  
Guard Cells ◽  
Stomatal Opening ◽  
Intercellular Spaces ◽  
Free Air ◽  
Detached Leaves

Stomata of Rumex sanguineus showed an aftereffect of wilting, those of previously wilted plants failing to open as widely as usual. The water content of previously wilted leaves recovered rapidly after watering. The wilting treatment killed about 2% of the guard cells, and was followed by a persistent 5.5 to 7% increase in the carbon dioxide compensation point of leaves. Replacing the air in the intercellular spaces with carbon-dioxide-free air did not remove the aftereffect of wilting on the stomata. Detached leaves also showed the aftereffect, although it was apparently smaller than in leaves attached to the plant. Neither persistent water deficits, nor killing of guard cells, nor increased intercellular space carbon dioxide concentration could explain the aftereffect of wilting on stomata. The results are, however, consistent with the view that an inhibitor of stomatal opening accumulates in leaves after a period of water stress or, alternatively, that there is a deficiency of a substance which promotes opening.

Die Stomata als Glieder eines schwingungsfähigen CO2-Regelsystems Experimenteller Nachweis an Zea mays L.

1965 ◽  
Vol 20 (12) ◽  
pp. 1261-1270 ◽  
Author(s):  
Klaus Raschke
Keyword(s):  
Carbon Dioxide ◽  
Zea Mays ◽  
Zea Mays L ◽  
Time Lag ◽  
Carbon Dioxide Concentration ◽  
Regulatory System ◽  
Guard Cells ◽  
Stomatal Movement ◽  
Intercellular Spaces

Using recording porometer techniques, evidence was produced for the existence of a regulatory system stabilizing the carbon dioxide concentration within the intercellular spaces of leaves. The guard cells function as effectors, and most probably also as sensors. Measurements by the cells of the carbon dioxide concentration and stomatal movement are two separate processes; the second requires auxiliary energy. The system reacts to disturbances after a time lag. This causes overshoot. Additional strong feedback may lead to stomatal oscillations which sometimes persist, or even increase in amplitude indicating insufficient damping.

Effects of temperature on the morphology and photosynthetic activity of newly matured leaves of alfalfa

1973 ◽  
Vol 51 (10) ◽  
pp. 1907-1916 ◽  
Author(s):  
S. B. Ku ◽  
L. A. Hunt
Keyword(s):  
Carbon Dioxide ◽  
Exchange Rate ◽  
Water Content ◽  
Intercellular Space ◽  
Leaf Water Content ◽  
Carbon Dioxide Exchange ◽  
Specific Leaf Weight ◽  
Leaf Density ◽  
Effects Of Temperature ◽  
Space Volume

Effects of temperature on (1) physical characteristics of newly matured leaves throughout regrowth, and (2) net carbon dioxide exchange–irradiance response curves throughout regrowth and throughout the day are described for two alfalfa (Medicago saliva L.) genotypes (AT171 and CC120) grown at 20/15C and 30/25C day/night temperatures and 53 nE cm−2 s−1 irradiance (400–700 nm).Area per leaf increased linearly with increasing leaf number up to the fourth or fifth leaf, and thereafter remained constant. Both specific leaf weight and leaf density were constant for the first four leaves, and increased sharply thereafter, particularly at day/night temperatures of 20/15C. Percentage of leaf water content did not change throughout regrowth at 30/25C, but decreased after leaf 4 at 20/15C. Intercellular space volume fluctuated with leaf number. Leaf area was larger, specific leaf weight, and leaf density were greater, intercellular space volume was higher, and percentage of leaf water content was lower, with plants grown at 20/15C than at 30/25C.The net carbon dioxide exchange rate at 116 nE cm−2 s−1 increased with leaves produced progressively until a peak was reached at leaf 4 or 5 and then decreased. At any given leaf position, net carbon dioxide exchange rate at 116 nE cm−2 s−1 was greater at 20/15C than at 30/25C for AT171, but was the same at both temperatures for CC120. In contrast, net carbon dioxide exchange rate at 76 nE cm−2 s−1 was greater at 20/15C than 30/25C for both genotypes. Net carbon dioxide exchange rates measured in the morning were always lower than those measured in the afternoon regardless of irradiance, genotype, and growth temperature.

Carbon dioxide enrichment and water stress interaction on growth of two tomato cultivars

1984 ◽  
Vol 102 (3) ◽  
pp. 687-693 ◽  
Author(s):  
Alejandra Paez ◽  
H. Hellmers ◽  
B. R. Strain
Keyword(s):  
Carbon Dioxide ◽  
Water Stress ◽  
Plant Growth ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Osmotic Potential ◽  
Water Status ◽  
Carbon Dioxide Concentration ◽  
Leaf Water ◽  
Total Leaf

SummaryIf atmospheric carbon dioxide concentration continues to increase, plant growth and crop yield could be affected. New Yorker and Better Boy cultivars of tomato (Lycopersicon esculentum) were used to investigate possible intraspecific variation in the response of crop species to increased CO2. Because precipitation and temperature are predicted to change with the increasing atmospheric CO2 concentration, the response of the two cultivars to the interaction between CO2 and water stress was also examined. Seeds of the two cultivars were germinated and grown under controlled environmental conditions, in either 350 or 675 μ1 CO2/1.The plant water status of the two cultivars was inherently different but was little affected by the CO2 concentration when the plants were well watered. When water was withheld for 5 days the total leaf water potential and osmotic potential decreased in both CO2 treatments but less rapidly in high CO2 than in low. Under low CO2 total leaf water potential decreased to a lower value than osmotic potential. The differences were due, at least in part, to the reduced stomatal conductance and transpiration rate under high CO2.Increased CO2 ameliorated the detrimental effects of drought stress on plant growth. The results indicate that increased CO2 could differentially affect the relative drought resistance of species cultivars.

scholarly journals Effect of Light Intensity and Leaf Temperature on Photosynthesis and Transpiration in Wheat and Sorghum

1970 ◽  
Vol 23 (4) ◽  
pp. 775 ◽  
Author(s):  
RW Downes
Keyword(s):  
Carbon Dioxide ◽  
Water Use ◽  
Carbon Dioxide Concentration ◽  
Leaf Temperature ◽  
High Light ◽  
Intercellular Spaces ◽  
Concentration Difference ◽  
Light Levels ◽  
Light Intensities ◽  
Water Vapour Concentration

Wheat stomata offered less resistance to water and carbon dioxide diffusion than sorghum stomata at light intensities of 0�06 and 0�26 cal cm-2 min-i (400-700 nm) but resistances were comparable at 0�46 cal cm-2 min-i. Consequently, transpiration rates were higher in wheat than in sorghum, except at the high light levels, in leaf chamber experiments described here. Rates of photosynthesis were higher in sorghum than in wheat, with the greatest difference at high light levels. This resulted in a greater efficiency of dry matter production relative to water use in sorghum. Transpiration rate increased with increased temperature in both species. Photosynthesis was independent of temperature in wheat, and in sorghum under low light conditions, but otherwise photosynthesis increased with temperature in sorghum. In both species, efficiency of water use decreased as temperature increased at all light intensities. Water vapour concentration difference between the intercellular spaces and the air was comparable in wheat and sorghum and increased with temperature. The carbon dioxide concentration difference between air and intercellular spaces was substantially greater in sorghum than in wheat and increased with leaf temperature. Maximum values were obtained at the intermediate light level in sorghum.

The rôle of abscisic acid and farnesol in the alleviation of water stress

1978 ◽  
Vol 284 (1002) ◽  
pp. 471-482 ◽  
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Carbon Dioxide Concentration ◽  
Vapour Pressure Deficit ◽  
Guard Cells ◽  
Chloroplast Envelope ◽  
Water Vapour Pressure ◽  
Second Line ◽  
Short Supply ◽  
Response To Water

The complex responses of stomata which provide protection for land plants against excessive water loss are best understood if we consider them as occupying two lines of defence. The first line of defence consists of immediate responses to factors of the aerial environment, especially carbon dioxide concentration and water vapour pressure deficit, which ensure that the rate of transpiration is regulated to a level which can be supported by water uptake through the roots in moist soil. When the soil becomes dry, further controls become necessary, and the second line of defence comes into operation. A ceiling is imposed on the extent to which stomata can open, and an increase in the efficiency of water use is achieved, though at the expense of some reduction in the rate of photosynthesis. A sesquiterpenoid, abscisic acid (ABA) plays a major part in the second line of defence. It is contained in the mesophyll chloroplasts in leaves of well watered plants and is released when the water potential falls; the synthesis of new ABA is also induced by water stress. Movement of ABA from the mesophyll to the guard cells is assumed to take place, because the chloroplasts of guard cells appear to be unable to form ABA in response to water stress. We suggest that farnesol, another sesquiterpenoid hitherto considered to have a separate role as a regulator of transpiration, is the agent responsible for altering the permeability of chloroplast envelope membranes, allowing the release of ABA into the cytoplasm. The closure of stomata induced by ABA appears to be part of a series of integrated responses throughout the plant which helps to maintain turgor and growth when water is in short supply.

scholarly journals Using New Gas Exchange Methods to Estimate Mesophyll Conductance and Non-stomatal Inhibition of Photosynthesis Caused by Water Deficits

HortScience ◽  
2012 ◽  
Vol 47 (6) ◽  
pp. 687-690 ◽  
Author(s):  
James Bunce
Keyword(s):  
Carbon Dioxide ◽  
Water Stress ◽  
Soil Water ◽  
Atmospheric Carbon Dioxide ◽  
Global Climate ◽  
Stomatal Closure ◽  
Carbon Dioxide Concentration ◽  
Mesophyll Conductance ◽  
Water Deficits ◽  
Air Space

Soil water deficits remain one of the most important factors reducing the yield of crop plants and may become even more limiting with changes in the global climate and competition for fresh water resources. Soil water deficits reduce plant growth partly by reducing photosynthesis. However, it remains unclear how important non-stomatal factors are in limiting photosynthesis under moderate water stress and whether rising atmospheric carbon dioxide may alter which processes limit photosynthesis under water stress. The conductance to CO2 from the substomatal air space to the site of carboxylation inside chloroplasts in C3 plants is now termed mesophyll conductance. Because of the competition between CO2 and O2 for RuBisco, the carbon dioxide concentration at the chloroplast can be estimated from the O2 sensitivity of photosynthesis, providing a new method of estimating mesophyll conductance. It has also recently been realized that partial stomatal closure resulting from water stress can often be reversed by exposing leaves to low CO2. This provides a new means of assessing the non-stomatal component of the inhibition of photosynthesis by water stress. These methods were applied to four C3 species and revealed that mesophyll conductance decreased substantially with water stress in two of the four species and that reopening of stomata did not eliminate the reduction in photosynthesis caused by moderate water stress at either the current ambient or elevated CO2 concentrations.

Structure, Carbon Dioxide Fixation and Metabolism of Stomata

1974 ◽  
Vol 1 (2) ◽  
pp. 221 ◽  
Author(s):  
CJ Pearson ◽  
FL Milthorpe
Keyword(s):  
Carbon Dioxide ◽  
Organic Acid ◽  
Co2 Fixation ◽  
Tricarboxylic Acid Cycle ◽  
Guard Cells ◽  
Tricarboxylic Acid ◽  
Light Illumination ◽  
Acid Cycle ◽  
Free Air ◽  
Positive Correlations

Studies were made of the structure and rates of CO2 fixation of epidermis and of changes in organic metabolites in Commelina cyanea during transition to light and dark in both normal and CO2-free air. Guard cells of C. cyanea and Vicia faba contain numerous highly developed mitochondria and starch-forming chloroplasts (mitochondria: chloroplast ratios of 3 : 1) in comparison to other epidermal cells with few mitochondria and rudimentary plastids without starch. Their rates of photosynthesis per chloroplast appeared to be at least as high as those of the mesophyll, but circumstantial evidence suggested that about half of current photosynthate was respired. The rate of CO2 fixation in the dark was about 0.2–0.4% of that in the light. Illumination caused an increase, and darkening a decrease, of aperture, malate, and organic acid 1% within the epidermis of C. cyanea. Darkening in CO2-free air was accompanied by only slight decreases in aperture and malate. There were close positive correlations between aperture and concentration of malate and between aperture and organic acid 14C. During opening, the rise in organic acid 14C was associated with a decline in amino acid 14C. It is suggested that organic acids may be formed through aspartate and possibly also from sugars and other amino acids entering the tricarboxylic acid cycle. Concentrations of sugars were not related to aperture although they increased on illumination and declined about 2 h after darkening. Polysaccharide concentrations in the epidermis of darkened leaves were similar to those in illuminated leaves.

Activity of solutions of methanol, ethanol and n -butanol on stomatal opening in presence or absence of carbon dioxide

1976 ◽  
Vol 273 (927) ◽  
pp. 561-564 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Osmotic Potential ◽  
Cell Membranes ◽  
Major Effect ◽  
Stomatal Opening ◽  
Redox Equilibrium ◽  
Pumping System ◽  
Free Air ◽  
Lipid Components

Of the three alcohols studied, n -butanol was the most effective. At 0.15 M it prevented stomatal opening whereas methanol has the same effect at 0.5 M and ethanol at 0.9 M. Cytoplasmic movement is not affected by n -butanol but the stomatal plastids are sometimes altered. It is supposed on the basis of numerous reports in the literature, that the lipophilic nature of this alcohol must have a major effect on the lipid constituents of the cell membranes and thus render impossible the maintenance of the low osmotic potential required for stomatal opening. This conclusion is supported by the fact that the stomata did not reopen in CO 2 free air. Another possible effect is a disturbance of the redox equilibrium of the cells, particularly the NADH 2 :NAD ratio, with the result that the active pumping system cannot perform the work required to drive in the cations. The lipid components of ATPase can also be damaged. It is concluded that when alcohols are used as solvents, care must be taken to avoid causing subtle membrane lesions.

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