Physiological and Anatomical Effects of Growth Temperature on Phaseolus vulgaris L. Cultivars

Two Phaseolus vulgaris L. cultivars were grown at 20/15, 25/20,and 30/25 °C day/night temperatures in growth chambers witha 16 h thermoperiod corresponding to the photoperiod. When thefirst trifoliolate leaf was fully expanded rates of CO₂ exchange(CER) were measured at 27 °C and saturating light usinginfrared gas analysis. Stomatal (r_s) and mesophyll resistances,CO₂ compensation points, activities of the enzymes ribulosebisphosphate carboxylase (RuBPCase), glycolate oxidase (GAO),malate dehydrogenase (MDH), and fructose-1, 6 diphosphate (FDP),chlorophyll content, Hill activities, and leaf anatomy at boththe light and electron microscope level were also investigatedin these leaves. Rates of CO₂ exchange in the light, transpiration rate, andchlorophyll content increased with increasing growth temperaturewhile leaf thickness, specific leaf weight, RuBPCase activity,compensation point, and stomatal resistance decreased. Mesophyllresistance also decreased when calculated assuming zero chloroplastCO₂ concentration (rm, o), but not when calculated assuminga chloroplast CO₂ concentration equal to the CO₂ compensationconcentration (rm, g). Average leaf size was maximal in 25/20°C plants while dark respiration, MDH activity, stomataldensity, and starch were minimal. The activities of GAO andFDP and Hill activity were not affected by temperature pretreatment.     

Cytokinin Effects on Leaf Architecture in Phaseolus vulgaris L.

Treatment of expanding primary leaves of bean plants (Phaseolnsvulgaris L. cv. Limburgse vroege) with benzyladenine (BA) orkinetin at 0.5 mM for five consecutive days resulted in thickerleaves showing a significant decrease in intercellular air spacevolume. Compared with control plants, exposed mesophyll cellsurface area was lower per unit tissue volume, but unchangedwhen expressed per unit leaf surface area. Stomata of treatedplants were not fully closed in the dark and they did not openas wide as controls in the middle of the light period, suggestingthat the treatment resulted in impaired stomatal action. Allthe effects mentioned were more pronounced after treatment withBA, compared to kinetin. In spite of their magnitude, the observedchanges in leaf structure and function did not seem to havean important effect on total leaf diffusion resistance to carbondioxide during the course of the light period. Key words: Cytokinins, Leaf architecture     

Leaf Growth in Phaseolus vulgaris: I. Growth of the first pair of leaves under constant conditions

The growth of the first pair of leaves of Phaseolus vulgaris(French bean) has been studied during germination and followingemergence of the seedling. The leaves are well developed inthe embryo and, at 22.5° C, show an exponential increasein fresh weight, dry weight, and leaf area up until about eightdays from planting. Cell division commences about two days afterplanting and is exponential for a short period. Considerablechanges in cell volume occur during the period over which celldivision occurs. Cell division ceases soon after emergence andunfolding, when the leaf has reached only 17 per cent of itsfinal area. Cessation of cell division is followed by a phaseof growth which is due entirely to cell expansion. The significanceof these findings is discussed in relation to recent work onother genera.     

Temperature Effects on Mitochondrial Respiration in Phaseolus acutifolius A. Gray and Phaseolus vulgaris L

Electron transport, using succinate as a substrate, was measured polarographically in mitochondria isolated from Phaseolus vulgaris and P. acutifolius plants at 25°C and 32°C. Mitochondria isolated from P. vulgaris plants grown at 32°C had reduced electron transport and were substantially uncoupled. Growth at 32°C had no effect on electron transport or oxidative phosphorylation in P. acutifolius compared to 25°C grown plants. Mitochondria isolated from 25°C grown P. vulgaris plants measured at 42°C were completely uncoupled. Similarly treated P. acutifolius mitochondria remained coupled. The uncoupling of P. vulgaris was due to increased proton permeability of inner mitochondrial membrane. The alternative pathway was more sensitive to heat than the regular cytochrome pathway. At 42°C, no alternative pathway activity was detected. The substantially greater heat tolerance of P. acutifollus compared to P. vulgaris mitochondrial electron transport suggests that mitochondrial sensitivity to elevated temperatures is a major limitation to growth of P. vulgaris at high temperatures and is an important characteristic conveying tolerance in P. acutifolius.     

Methylammonium Transport in Phaseolus vulgaris Leaf Slices

Methylammonium (as a nonmetabolized analog of ammonium) transport was studied in leaf slices of Phaseolus vulgaris L. var. `Hawkesbury Wonder.' The relationship of influx to external pH (6.0-10.5) shows that the influx at low external pH is a larger fraction of that at high external pH than would be expected from the pK_α of methylammonium and the assumption that only CH₃NH₂ is entering the cells. The relationship between methylammonium influx and external methylammonium concentration shows some evidence of saturation; this is a function of the transport system rather than of the (limited) methylammonium metabolism in the cells. The “equilibrium” concentration ratio for methylammonium between leaf slices and bathing medium is far higher than can be explained by the transport of CH₃NH₂ alone and the pH of the compartments involved. These three lines of evidence strongly suggest that there is an influx of CH₃NH₃⁺, possibly by a uniporter driven by the electrical potential of the cytoplasm with respect to the medium, as has been shown for other plant cells. Competitive inhibition of methylammonium influx by ammonium suggests that there is also an ammonium transport system. The significance of this for the recycling of N within the plant and for exchange of gaseous NH₃ between leaves and the atmosphere is discussed.     

Thigmomorphogenesis: The Interaction of Wind and Temperature in the Field on the Growth of Phaseolus vulgaris L.

Field and laboratory experiments were performed to determinethe interaction of wind and temperature on thigmomorphogenesis(defined here as decreased elongation and increased internodalradial enlargement due to mechanical perturbation). Kidney beanplants (Phaseolus vulgaris L. cv. Red Cherokee Wax) were shelteredor exposed to wind for 10 days. Wind velocity, wind gusting,temperature, light and rainfall were measured for the durationof each of ten experiments. Stem elongation and diameter weremeasured and it was found that thigmomorphogenesis due to windoccurs naturally. There was more internodal secondary xylemproduced in the wind-exposed plants than in the sheltered plants.The experimental data were analyzed by multiple linear regressionand the wind was found to be a significant factor in the predictionof bean stem elongation and thickening. Laboratory experimentsshow that as wind velocity increases, thigmomorphogenesis increasesin an approximate linear fashion. Furthermore, it was foundthat low temperatures interact with mechanical perturbationto reduce the amount of thigmomorphogenesis, both in the fielddue to wind and in the laboratory due to rubbing. Other environmentalfactors do not seem to interact with the wind to modulate thigmomorphogenesiseven though these factors affect plant growth. Phaseolus vulgaris L., kidney bean, thigmomorphogenesis, wind, temperature, ethylene, multiple linear regression     

Effects of Anoxia and Red Light on Changes Induced by Blue Light in the Membrane Potential of Pulvinar Motor Cells and Leaf Movement in Phaseolus vulgaris L.

In the dark, the membranes of the pulvinar motor cells of Phaseolusvulgaris L. were rapidly depolarized under anoxic conditionsand repolarized with re-aeration. This change in potential mayhave been due to suppression by anoxia of a respiration-dependent,electrogenic ion pump in the motor cells. When the pulvinuswas irradiated with blue light (BL) in the depolarized stateunder anoxic conditions, no marked depolarization occurred.Furthermore, a short pulse of BL did not induce transient depolarization.On continuous irradiation with red light (RL), the motor cellunder anoxic conditions showed slow recovery of the depolarizedmembrane potential. When a pulse of BL was superimposed on theRL after the recovery, transient depolarization occurred again. The leaf showed a small downward movement under anoxic conditionsbut recovered with re-aeration. Upward movement of the leafcaused by continuous application of BL to flexor cells changedto a downward movement under anoxic conditions, and re-aerationled to a return to upward movement. Unidirectional irradiationby BL of the flexor side did not cause upward movement of theleaf under anoxic conditions. However, unidirectional irradiationof RL to the flexor side caused downward movement of the leafunder anoxic conditions, which could be changed to upward movementby superimposition of irradiation with BL. The experimentalresults clearly show that BL acts mainly to inhibit (depolarize)an electrogenic component of the membrane potential in pulvinarmotor cells which is dependent on a supply of energy from respirationor photophsphorylation. (Received November 1, 1989; Accepted April 12, 1990)     

An Association Between Acid Invertase Activity and Cell Growth during Leaf Expansion in Phaseolus vulgaris L.

Changes in lamina area, dimensions of epidermal and palisadecells, acid invertase activity and content of sucrose and hexosein the primary leaves of Phaseolus vulgaris L. were determinedbetween emergence of the hypocotyl hook and the completion ofleaf expansion. Growth in area and thickness of the primaryleaf after emergence was attributable to the expansion of cellsalready present in the lamina at emergence. The major invertasein the expanding leaf was a readily soluble acid invertase;little insoluble invertase activity was detected. Soluble andinsoluble fractions of leaf homogenates contained little neutralinvertase activity. The specific activity of the soluble acidinvertase increased rapidly during the early stages of leafexpansion, reaching a peak at the time of most rapid cell enlargement(5 d after emergence) and then declining as the leaf matured.Highly significant positive correlations were found betweenenzyme specific activity and the rates of cell and leaf enlargement. The early, rapid phase of lamina expansion was characterizedby high concentrations of hexose sugar and low concentrationsof sucrose. As the rates of leaf cell enlargement declined theconcentration of hexose fell and that of sucrose increased.Between 5 d and 11 d after hypocotyl emergence, the hexose/sucroseratio in the primary leaf decreased approximately 10-fold asthe specific activity of acid invertase decreased. The results are discussed with reference to sources of carbonsubstrates for cell growth and to the sink/source transitionduring leaf development. Key words: Leaf expansion, Acid invertase, Hexose, Sucrose, Phaseolus     

The Effect of Salinity on Growth of Phaseolus vulgaris L.: I. Anatomical Changes in the First Trifoliate Leaf

When plants of Phaseolus vulgaris were grown in culture solutioncontaining 48 m mol l^–1 sodium chloride, the first trifoliateleaves were always smaller in area than those of control plants.The leaves of the salt-treated plants however could become thicker.This increase in thickness was brought about by the increasein the thickness of the spongy parenchyma layer. The palisadeparenchyma layer was always thinner than that in the controlleaves. While these latter leaves expanded predominantly bycell division, this only held for the early stages of expansionof the leaves of salt-treated plants. In this case cell divisionceased when the leaves were about half their maximal size andfurther increase in area was brought about by an increase involume of the spongy parenchyma cells.     

Physiological Stress and Crystallites in Leaf Plastids of Phaseolus vulgaris L.

Crystalline inclusions were found in leaf plastids of Phaseolusvulgaris L. cultivar Limburg when excised plant parts were used.Removal of the root system induced crystalloid production afteran incubation period of optimal length. In agreement with thefindings of other authors physiological stress seems to be theunderlying condition of crystal formation in plastids.     

The Effect of Low Temperature on Ethylene Production by Leaf Tissue of Phaseolus vulgaris L.

When leaf discs cut from primary leaves of Phaseolus vulgarisL. cv. Masterpiece plants grown at 25°C were incubated attemperatures below 25 °C, basal and wound ethylene productioncontinued at reduced rates. In both cases detectable levelsof ethylene were produced at 25 °C. When the rates of ethyleneproduction were plotted according to the Arrhenius equationa marked discontinuity was found at 11.4 °C which is consistentwith a membrane phase-transition at the critical chilling temperatureof the plant. Activation energies for the rate-limiting enzymereaction in ethylene production above and below the criticaltemperature have been calculated and the data interpreted asindicating the involvement of membrane-bound enzyme systemsin the biosynthesis of basal and wound ethylene. ethylene, temperature, Arrhenius plot, activation energy, Phaseolus vulgaris L., bean     

Light and Hormone Interaction in Apical Dominance in Phaseolus vulgaris L.

Gibberellic acid (GA₂), kinetin, and indole-3yl-acetic acid(IAA) each at four concentrations (0, 0.5, 5, and 50 µM)were applied alone and in all possible combinations to rootsof Phaseolus vulgaris L. grown under four different light regimes(7000, 14 000, 21 000, and 28 000 lx). GA₃ increased growthof main stem and laterals but reduced apical dominance, especiallyin the absence of, or at low kinetin concentrations. A highlevel of kinetin lowered GA₃ induced growth of main stems and,to a lesser extent, laterals. Kinetin greatly reduced apicaldominance, especially in the absence of, or at low GA₃ concentrations.IAA slightly reduced growth of main stems and laterals and slightlyincreased apical dominance. Generally the magnitude of the IAAeffects were less than those of GA₃ or kinetin and there wereless interaction between IAA and other factors than betweenGA₃ or kinetin and other factors. Light affected growth of bothmain stem and laterals but the effect was dependent on GA₃ andkinetin levels and the interactions were complex. Generallya hormone balance seems to be operative with gibberellin-promotinggrowth of main stem and laterals and cytokinins and possiblyauxins preventing excessive elongation. Differential responsesbetween main stem and lateral may be due to different localhormone concentrations and over-all responses may be temperedby light intensity.     

Control of Thylakoid Growth in Phaseolus vulgaris

An attempt was made to answer whether the extent of thylakoid growth in Phaseolus vulgaris is controlled by a feedback inhibition mechanism, operating after insertion of all of the necessary components of the mature thylakoid, in the right amounts and ratio, or by parameters independent of the developmental stage of the membrane. This was done by following the growth of thylakoids, as monitored by the rate of chlorophyll accumulation and the rate of thylakoid protein synthesis, in etiolated plants exposed either directly to continuous light (transformation of prolamellar body to mature thylakoid) or first to periodic light and then to continuous light (transformation of prolamellar body to primary thylakoids and then to mature thylakoids). It was found that prolonged etiolation has no effect on the rate of thylakoid synthesis in continuous light. However, prolonged preexposure to periodic light diminishes drastically the rate of new thylakoid synthesis in continuous light. Since the thylakoids formed in the latter case are far from being complete, it seems that thylakoid growth can stop long before all of the necessary components are incorporated. Parameters independent of the developmental stage and composition of the membrane, therefore, seem to control membrane growth.     

A Relationship between Membrane Permeability and Ethylene Production at High Temperature in Leaf Tissue of Phaseolus vulgaris L.

Leaf discs cut from primary leaves of Phaseolus vulgaris L cvMasterpiece were incubated at temperatures higher than the growthtemperature of 25 °C Both basal and wound ethylene productionincreased up to temperatures of 35–37 5 °C, thereafterdeclining rapidly There was no detectable ethylene productionat temperatures above 42 5 °C Exposure of leaf discs tohigh temperature for 60 mm resulted in a large production ofwound ethylene when they were returned to 25 °C The magnitudeof ethylene production was related to the initial incubationtemperature as was the length of the lag period before maximumproduction was achieved The results are discussed in relationto the requirement for continued membrane integrity for ethyleneproduction ethylene, temperature, membrane permeability, Phaseolus vulgaris L, dwarf bean     

Influence of Soil and Air Temperature on I. Nucleotide Metabolism and Growth of Phaseolus vulgaris L. seedlings

Eight day old greenhouse grown Phaseolus vulgaris L. seedlingswere exposed to three different temperature regimes. The concentrationof the total free nucleotides, nucleoside triphosphates, RNAand protein was much more pronounced in seedlings exposed tothe interactive day/night temperature of 28 ?C (soil) and 15?C (air) of regime I. Seedlings treated to a low soil/air, day/nighttemperature of 15 ?C (regime II) had the lowest content of totalfree nucleotides, nucleoside triphosphates, RNA and protein.The nucleoside triphosphate content and energy charge valueof seedlings treated to a high soil/air, day/night temperatureof 28 ?C (regime III) declined much earlier than in the seedlingsexposed to temperature regimes I and II. The fresh and dry weightof seedlings exposed to temperature regime I was significantlyhigher than those seedlings exposed to the other two temperatureregimes. The slowest growth was observed in seedlings exposedto temperature regime II. The noticeably higher concentrationof ATP, pyridine nucleotides and root nodulation in seedlingsexposed to temperature regime I suggests that higher soil andlow air temperature enhances nitrogen metabolism in P. vulgarisseedlings.     

Abscisic Acid Decreases Leaf Na+ Exclusion in Salt-Treated Phaseolus vulgaris L.

Previous results showed that in short-term NaCl-treated beans increased leaf abscisic acid (ABA) concentration was triggered by Na⁺ but not by Cl^-. In this work, the specificity of ABA signaling for Na⁺ homeostasis was studied by comparing the plant’s responses to solutions that modified accumulation of ABA and/or Na⁺ uptake and distribution, such as supplemental Ca²⁺, increased nutrient strength, different isosmotic composition, application of exogenous ABA, fluridone (an ABA inhibitor) and aminooxiacetic acid (AOA, an ethylene inhibitor). After fluridone pretreatment, salt-treated beans had lower Na⁺ uptake and higher leaf Na⁺ exclusion capacity than non-pretreated plants. Moreover, Na⁺ uptake was increased and leaf Na⁺ exclusion was decreased by AOA and ABA. NaCl and KCl similarly increased leaf ABA and decreased transpiration rates, whereas supplemental Ca²⁺ and increased strength nutrient solution decreased leaf ABA and leaf Na⁺. These results show (1) a non-ion-specific increase in ABA that probably signaled the osmotic component of salt, and (2) increased ABA levels that resulted in higher leaf Na⁺ concentrations due to lower Na⁺ exclusion or increased root-shoot Na⁺ translocation.     

The Effects of Light Breaks in the Dark Period on Flower-bud Development in Varieties of Phaseolus vulgaris L.

A light break imposed in the middle of, or more effectively,two-thirds of the way through a 13 h dark period inhibited thedevelopment of the first initiated flower buds and reduced theproduction of open flowers in two daylength-sensitive varietiesof Phaseolus vulgaris. The effects were similar to those ofa long photoperiod applied continuously and therefore provideclear evidence of the importance of the dark period in mediatingthe effects of daylength on flower-bud development in the twovarieties. Phaseolus vulgaris, bean flower-bud development, photopcriodism     

The Effects of CO2 Enrichment and Nutrient Supply on Growth Morphology and Anatomy of Phaseolus vulgaris L. Seedlings

Plants of Phaseolus vulgaris were grown from seed in open-topgrowth chambers at the present (P, 350 µmol mol^–1)atmospheric CO₂ concentration and at an elevated (E, 700 µmolmol^–1) CO₂ concentration, and at low (L, without additionalnutrient solution) and high (H, with additional nutrient solution)nutrient supply for 28 d The effects of CO₂ and nutrient availabilitywere examined on growth, morphological and biochemical characteristics Leaf area and dry mass were significantly increased by CO₂ enrichmentand by high nutrient supply Stomatal density, stomatal indexand epidermal cell density were not affected by elevated CO₂concentration or by nutrient supply Leaf thickness respondedpositively to CO₂ increasing particularly in mesophyll areaas a result of cell enlargement Intercellular air spaces inthe mesophyll decreased slightly in plants grown in elevatedCO₂ Leaf chlorophyll content per unit area or dry mass was significantlylower in elevated CO₂ grown plants and increased significantlywith increasing nutrient availability The content of reducingcarbohydrates of leaves, stem, and roots was not affected byCO₂ but was significantly increased by nutrient addition inall plant parts Starch content in leaves and stem was significantlyincreased by elevated CO₂ concentration and by high nutrientsupply Phaseolus vulgaris, elevated atmospheric CO₂, CO₂-nutrient interaction, stomatal density, leaf anatomy, chlorophyll, carbohydrates, starch