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1.
J. J. Alarcón M. J. Sánchez-Blanco M. C. Bolarín A. Torrecillas 《Physiologia plantarum》1993,89(3):441-447
Cultivated tomato Lycopersicon esculentum (L.) Mill. cv. P-73 and its wild salt-tolerant relative L. pennellii (Correll) D'Arcy accession PE-47 growing on silica sand in a growth chamber were exposed to 0, 70, 140 and 210 m M NaCl nutrient solutions 35 days after sowing. The saline treatments were imposed for 4 days, after which the plants were rinsed with distilled water. Salinity in L. esculentum reduced leaf area and leaf and shoot dry weights. The reductions were more pronounced when sodium chloride was removed from the root medium. Reduction in leaf area and weight in L. pennellii was only observed after the recovery period. In both genotypes salinity induced a progressive reduction in leaf water potential and leaf conductance. During the recovery period leaf water potential (ψ1 ) and leaf conductance (g1 ) reached levels similar to those of control plants in wild and cultivated species, respectively. Leaf osmotic potential at full turgor (ψos ) decreased in the salt treated plants of both genotypes, whereas the bulk modulus of elasticity was not affected by salinity. Leaf water potential at turgor loss point (ψtlp ) and relative water content at turgor loss point (RWCtlp ) appeared to be controlled by leaf osmotic potential at full turgor (ψos ) and by bulk modulus of elasticity, respectively. At lowest salinity, the wild species carried out the osmotic adjustment based almost exclusively on Cl− and Na+ , with a marked energy savings. Under highest salinity, this species accommodate the stress through a higher expenditure of energy due to the contribution of organic solutes to the osmotic adjustment. The domesticated species carried out the osmotic adjustment based always on an important contribution of organic solutes. 相似文献
2.
Stomatal responses of pearl millet (Pennisetum americanum [L.] Leeke) to leaf water status and environmental factors in the field 总被引:3,自引:2,他引:1
I. E. HENSON G. ALAGARSWAMY F. R. BIDINGER V. MAHALAKSHMI 《Plant, cell & environment》1982,5(1):65-74
Abstract. Factors affecting stomatal conductance (g1 ) of pearl millet ( Pennisetum americanum [L.] Leeke), cultivar BJ 104, were examined in the field in India during the dry season.
Diurnal changes in g1 were evaluated for upper expanded leaves at flowering on two occasions using plants subjected to varying degrees of water stress. Except for the most severely stressed treatment, diurnal changes in g1 closely matched changes in irradiance ( I ), the promotive effect of which largely overcame opposing influences on g1 of increasing atmospheric vapour pressure deficit, and decreasing leaf water and turgor potentials (Ψ, Ψp ).
Two main effects of water stress on g1 were evident: (i) a decrease in the amplitude of the mid-day peak in g1 , and (ii) a decrease in the time over which high g1 was maintained, resulting in early (mid-day) closure and hysteresis in the relationship between g1 and I .
Leaf conductance was greatest for upper leaves and decreased down the canopy. At equivalent depths in the canopy g1 was higher in flowering than in photoperiodically-retarded plants of the same age. The magnitude of water stress-induced stomatal closure increased down the plant, and was more marked in retarded than in flowering plants.
Within individual stress treatments Ψ of upper leaves decreased linearly as transpiration flux increased. It is concluded that stomatal behaviour of upper leaves of pearl millet at flowering largely operates to maximize assimilation rather than to minimize water loss. 相似文献
Diurnal changes in g
Two main effects of water stress on g
Leaf conductance was greatest for upper leaves and decreased down the canopy. At equivalent depths in the canopy g
Within individual stress treatments Ψ of upper leaves decreased linearly as transpiration flux increased. It is concluded that stomatal behaviour of upper leaves of pearl millet at flowering largely operates to maximize assimilation rather than to minimize water loss. 相似文献
3.
Changes in free polyamine levels induced by salt stress in leaves of cultivated and wild tomato species 总被引:19,自引:0,他引:19
Ana Santa-Cruz Manuel Acosta Francisco Pérez-Alfocea Maria C. Bolarin 《Physiologia plantarum》1997,101(2):341-346
The effects of Na Cl on endogenous free levels of the poluamines putrescine, spermi dine and spermine, and the relationships between polyamines, K+ levels and Na+ accumulation were determined in leaves of the cultivated tomato ( Lycopersicon esculentum Mill.) and its wild, salt-tolerant relative L. pennellii (Correll) D' Arcy at different exposure times during a 32-day period. Both stress treatments (100 and 200 m M NaCl) decreased the levels of putrescine and spermidine, although to a different degree for the cultivated and wild tomato species. The spermine levels did not decrease with salinity in L. pennellii over the salinization period, whereas they decreased in L. esculentum , except at the first application of the 100m M NaCl treatment. In both species, the changes induced by salinity in total polyamines and K+ were very similar, with the accumulation of Na+ in the leaf being concomitant with a decrease in both total polyamines and K+ . This suggests that the main role of the polyamines in the leaf tissues. In this sense, a direct relationship between total polyamines and K+ , and inverse relationship between polyamines and Na+ and between K+ and Na+ were found for both species. In the short term (up to 4 days) a peculiar physiological behavior was found in L. pennellii , as the total polyamine and K+ levels decreased at 100 m M but not at 200 m M NaCl, while after this time the latter plants had values lower than those of the 100 m M NaCl-treated plants at day 11. 相似文献
4.
Salinity effects on growth and carbon balance in Lycopersicon esculentum and L. pennellii 总被引:1,自引:0,他引:1
Edith L. Taleisnik 《Physiologia plantarum》1987,71(2):213-218
The effects of salinity on growth and carbon balance in the cultivated tomato Lycopersicon esculentum (L.) Mill. cv. VF 234 and in a wild, salt-tolerant relative, L. pennellii (Correll) D'Arcy accession Atico, were compared. The level of salinity that significantly reduced growth and affected morphology was lower for the cultivated than for the wild species.
Net CO2 fixation, stomatal conductance and the specific activity of ribulose bisphosphate carboxylase (EC 4.1.1.39) were more decreased by salinity in the wild tomato than in the cultivated. In both species, the salinity-associated decrease in assimilation was related to a decrease in net photosynthesis and to carbon reallocation favoring heterotrophic organs. 相似文献
Net CO
5.
Developmental changes in tomato fruit composition in response to water deficit and salinity 总被引:6,自引:0,他引:6
Processing tomato ( Lycopersicon esculentum Mill. cv. UC82B) plants were subjected to moderate levels of water deficit and salinity (Na2 SO4 /CaCl2 ) in sand culture. Fruit water content and the relative contributions of organic and inorganic constituents to fruit solute potential (Ψ ) and soluble solids content were determined throughout development. Fruit Ψ averaged –0.63, –0.86 and –0.77 MPa in the control, salinity and water deficit plants, respectively. Reduced net water import and maintenance of solute accumulation, irrespective of water import, accounted for the reductions in Ψ of stressed fruits. Mineral ions (Na+ , K+ , Ca2+ , Mg2+ , Cl− and SO2- 4 ) contributed –0.31 MPa to Ψ in salinized fruit, compared with –0.19 MPa in control and water deficit treatments. Changes in net carbon accumulation were not observed among treatments, despite considerable differences in fruit K+ status. Starch accumulation in immature fruit was increased and hexose accumulation was decreased by both salinity and water deficit. Maximum starch levels were negatively correlated with total fruit Ψ , but were independent of fruit K+ . Organic acid levels were generally higher throughout development in salinized plants, relative to control plants, and correlated with increased inorganic cation rather than anion accumulation in these fruits. 相似文献
6.
Lewis H. Ziska Robert B. Hutmacher Glen J. Hoffman Theodore M. DeJong 《Physiologia plantarum》1989,77(1):141-149
Seasonal and diurnal measurements of leaf water potential (ψ1 ), relative water content (RWC) and stomatal conductance (gs ) were made in the field on 19-year old Prunus salicina (L.) cv. Santa Rosa, a deciduous fruit tree species, irrigated with 3 different concentrations of saline water over a 3 year period (1985-1987). With the exception of stage III of fruit growth, little or no treatment difference in Φ1 , leaf turgor potential (Φp ), or RWC was noted during the day. Seasonal averages of morning (0700-0900) and afternoon (1500-1700) Φp did not decline with increasing salinity, indicating long-term osmotic adjustment in this species. Maintenance of leaf water status under saline conditions was in part a consequence of increased stomatal closure, with a subsequent reduction in leaf transpiration rate. However, during stage III of fruit growth, an increase in mean afternoon (1200-1700) stomatal conductance of 26-117%, independent of salinity treatment, was observed in 1985 and again in 1987. Higher conductance values during this period may be associated with rapid fruit expansion and greater assimilate demand. The observed increase in conductance resulted in greater leaf water loss and larger measured differences in midday ψ1 between salinity treatments. This research indicates that for Prunus salicina in the field, salinity stress resulted in leaf water deficits only during the final period of fruit expansion and ripening. 相似文献
7.
Gilles Guerrier 《Physiologia plantarum》1996,97(3):583-591
NaCl (140 m M ) was applied to 14-day-old plants of salt-sensitive Lycopersicon esculentum Mill. cv. Volgogradskij and its wild relative L. pimpinellifolium Mill. accession PE-2. Changes in the relative growth rate of whole plant, and in the levels of inorganic and organic solutes in leaves, stems and roots were followed for 15 days after the application. Short-term salt exposure (4–6 days of salinization) resulted in enhanced relative growth rates for L. pimpinellifolium , but did not affect growth of L. esculentum , After 6 days of salinization, the relative growth rates of both species decreased significantly; leading to practically comparable growth rates for them by day 15. In all parts of both species, the contribution of organic solutes to the osmotic potential (Ψs ) gradually decreased from 30% on day 0 to a value lower than 5% on day 4. In L. pimpinellifolium , compared to L. esculentum , short-term salt exposure resulted in (1) a higher percentage of adjustment of Ψs ; and (2) increases in Na+ and K+ uptake rates, and in the levels of organic acids and proline (the level of which reached that of sugars, i.e., 10 μmol g-1 dry weight. Conversely, in L. esculentum , drastic reductions of K+ uptake rates and organic acid levels occurred already on day 1. During long-term salt exposure, both species were able to adjust osmotically and both exhibited decreases in organic acid levels as well as in K+ uptake and accumulation rates in all parts. The results are discussed in an attempt to explain the adaptive responses during short-term salt exposure and the metabolic dysfunctions that lead to growth decrease after long-term exposure to salt. 相似文献
8.
Evaluation of salt tolerance in cultivated and wild tomato species through in vitro shoot apex culture 总被引:8,自引:0,他引:8
Cano Emilio A. Pérez-Alfocea Francisco Moreno Vicente Caro Manuel Bolarín Maria C. 《Plant Cell, Tissue and Organ Culture》1998,53(1):19-26
The possibility of using in vitro shoot apex culture to evaluate salt tolerance of cultivated (Lycopersicon esculentum Mill.)
and wild (Lycopersicon pennellii (Correll) D'Arcy) tomato species was determined and related to the response obtained by callus
culture. Both apices and calluses were grown on media supplemented with 0, 35, 70, 105, 140, 175 and 210 mM NaCl, and growth
and physiological traits were determined. Most apices of L. esculentum did not develop roots from low NaCl levels, whereas
the apices of L. pennellii were able to develop roots at the different salt levels. This different degree of salt tolerance
between L. esculentum and L. pennellii was not, however, clearly shown on the basis of the shoot growth of the plantlets.
The callus response was similar to that shown by the rooting parameters, as callus growth in response to increased salinity
was much greater in L. pennellii than in the tomato cultivar. K+decreased more and proline accumulated less with salinity in shoots of L. esculentum compared to L. pennellii, whereas the
opposite response was obtained in calluses. The results obtained in this study suggest that rooting parameters are the most
useful traits for rapid evaluation and screening of tomato species and segregating populations through in vitro shoot apex
culture.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
GA1 , GA8 , GA17 , GA19 , GA20 and GA29 were identified by combined gas chromatography-mass spectrometgry (GC-MS) in immature seeds and pericarp of Lycopersicon esculentum Mill. (tomato). Higher levels of these GAs were present in the seeds than in the pericarp; seeds in addition contained GA15 , GA24 , GA25 , and GA44 . Fruits of the Lycopersicon pimpinellifolium Mill. mutant I were smaller and contained lower GA1 concentrations, but higher GA20 concentrations, than those of mutants III and IV. In contrast, differences in fruit size in L. esculentum due to position on the truss did not correlate with GA1 concentration in either the pericarp or seeds. 相似文献
10.
Non-steady state xylem transport of fifteen elements into the tomato leaf as measured by gamma-ray spectroscopy: A model 总被引:1,自引:0,他引:1
A model describing the transport of elements through the xylem vessels into the leaf of a red cherry tomato ( Lycopersicon esculentum Mill cv. Tiny Tim) in a non-steady state situation is presented. The model describes the upward movement of ions as a mass-flow of the xylem fluid with dissolved elements, with lateral ion escape represented by a first-order process. The model is fitted to data obtained in an experiment in which 15 elements were applied in a solution to a cut stem part with attached leaf and were measured simultaneously by gamma-ray spectroscopy. The model is in good agreement with the transport into the leaf of K+ Na+ , Rb+ , Cs+ , Yb3+ , Sm3+ Zn2+ , Co2+ , Cu2+ , Sb(SO4 )2 AsO3+ 4 , WO2+ 4 ; and Mo7 O6+ 24 .
Only indirect data could be obtained for Cd2+ and La3+ because of their apparently high affinity for charged sites in the cell walls and high escape constant, respectively. The escape constants were relatively low for all anions, probably due to the presence of a large number of negative charges in the cell walls. 相似文献
Only indirect data could be obtained for Cd
11.
The growth of the wild tomato species Lycopersicon peruvianum (L.) Mill, and L. pennellii (Correll) D'Arcy, was compared with that of the cultivated tomato, L. esculentum Mill. cv. VE 234, under conditions of reduced K+ supply. Growth was impaired less in the wild than in the cultivated species. The higher efficiency of K+ utilization in the wild species was not associated with more efficient JC uptake from the medium. The rate of K+ uptake by whole plants was similar in the three species, but the rate of uptake by detached root tips was lower in the wild species. The permeability of the plasma membrane to K+ was apparently similar in root tips of the three species, but the tonoplast permeability was much lower in the wild than in the cultivated species. 相似文献
12.
Effects of chloride and sodium on gas exchange parameters and water relations of Citrus plants 总被引:9,自引:0,他引:9
Gas exchange parameters, water relations and Na+ /Cl- content were measured on leaves of one-year-old sweet orange ( Citrus sinensis [L.] Osbeck cv. Hamlin) seedlings grown at increasing levels of salinity. Different salts (NaCl, KCl and NaNO3 ) were used to separate the effects of Cl− and Na+ on the investigated parameters. The chloride salts reduced plant dry weight and increased defoliation. Accumulation of Cl− in the leaf tissue caused a sharp reduction in photosynthesis and stomatal conductance. By contrast, these parameters were not affected by leaf Na+ concentrations of up to 478 m M in the tissue water. Leaf water potentials reached values near −1.8 MPa at high NaCl and KCl supplies. This reduction was offset by a decrease in the osmotic potential so that turgor was maintained at or above control values. The changes in osmotic potential were closely correlated with changes in leaf proline concentrations. Addition of Ca2+ (as calcium acetate) increased growth and halved defoliation of salt stressed plants. Furthermore, calcium acetate decreased the concentration of Cl− and Na+ in the leaves, and increased photosynthesis and stomatal conductance. Calcium acetate also counteracted the reductions in leaf water and osmotic potentials induced by salinity. In addition, calcium acetate inhibited the accumulation of proline in the leaves which affected the reduction in osmotic potential. These results indicate that adverse effects of salinity in Citrus leaves are caused by accumulation of chloride. 相似文献
13.
Water stress induced changes in concentrations of proline and total soluble sugars in nodulated alfalfa (Medicago sativd) plants 总被引:1,自引:0,他引:1
Susceptibility of alfalfa ( Medicago saliva L. cv. Aragón) nodules and leaves to water stress has been investigated. Nodule acetylene reduction activity (ARA), leaf CO2 exchange rate (CER) as well as soluble protein, proline and total soluble sugar (TSS) contents were determined during drought. Water status was estimated as water potential (Ψw ) and Relative water content (RWC) of the respective tissues. Maximum rates of ARA required higher Ψw than CER. Nodules had lower RWC for a given Ψw than leaves. Water stress reduced soluble protein content in both tissues; however, the decline in soluble protein content was detected at greater Ψw in nodules than in leaves. Proline and TSS increased in leaves and nodules, and again the threshold Ψw triggering such accumulation was higher in nodule tissues. Oior results suggest that alfalfa nodules are more susceptible to water shortage than leaves. Effects of accumulated TSS and proline upon leaf and nodule physiology are discussed in relation to protein stability (proline), pH control (proline) and osmotic adjustment (proiine and TSS). The TSS accumulation induced by water stress suggests that substrate shortage would not be the primary effect of drought on nodule activity. 相似文献
14.
Olfa Ayari Guy Samson Martine Dorais Rénald Boulanger André Gosselin 《Physiologia plantarum》2000,110(4):558-564
In May, greenhouse tomato ( Lycopersicon esculentum Mill.) plants near the end of their winter production cycle were shown to exhibit a diurnal photosynthetic decrease. In order to identify the physiological causes of this decline, we compared in May the photosynthetic characteristics of the fifth youngest leaves from tomato plants of different ages corresponding to a winter production (11-month-old plants) and to a spring production (5-month-old plants). Although the leaves were developed simultaneously under the same environmental conditions, only the ones from the winter production showed a diurnal decline of the in situ CO2 assimilation rate (A CO 2 ). This was accompanied by a decline of internal CO2 and stomatal conductance and by large accumulations of hexoses. When stomatal closure was relieved under saturated CO2 concentration (5%) using a leaf-disc electrode system, the fifth leaves of both tomato cultures had similar maximum quantum efficiency of O2 evolution (Φmax ), light-saturated rate of O2 evolution (Pmax ) and quantum efficiency of photosystem II (PSII) photochemistry (ΔF/F'm , q P and q N ). We concluded that the diurnal decline of A CO 2 observed in winter tomato production during May originates from a stomatal limitation that is not dependent on environmental conditions but rather related to the developmental stage of the plants. 相似文献
15.
Vittorio Raggi 《Physiologia plantarum》1992,84(4):537-548
Bean plantlets ( Phaseolus vulgaris L. cv. Topcrop) were stressed at the age of 16–18 days by gradual (2–8%) or abrupt addition of 6% (w/v) polyethylene glycol Mw 6000 (PEG 6000) to Hoagland solution. Leaf conductance, photosynthesis, internal CO2 partial pressure (Ci ), relative water content (RWC), water content/dry weight (H2 O/DW), apoplastic PEG concentrations and weight of leaves, stems and roots were determined. Leaf conductance, photosynthesis and Ci were determined on non-detached primary leaves, and leaf potentials (water, osmotic and turgor potentials) were investigated in freshly detached (non-rehydrated) primary leaves, both in treated and control plants; RWC and osmotic potential were also assessed at the null turgor point. Low PEG 6000 concentrations induced early and evident decrease in leaf conductance and photosynthesis, whereas Ci decreased only moderately and tended to recover during advanced stress. There were moderate though significant decreases in RWC and H2 O/DW, no change or increases in water potential, no significant changes in osmotic potential and a moderate but significant increase in turgor potential. Even when referred to null turgor point, RWC significantly decreased and osmotic potential was unchanged. It was concluded that apoplastic PEG 6000 accumulation at evaporating sites would account for the early decrease in conductance which would also justify the unchanged or the prevalent increase in water potential and turgor potential. The subsequent PEG diffusion and concentration in the leaf apoplastic water would have induced the RWC and H2 O/DW decrease and the final turgor flexion documented. 相似文献
16.
DANIEL M. JOHNSON FREDERICK C. MEINZER DAVID R. WOODRUFF & KATHERINE A. MCCULLOH 《Plant, cell & environment》2009,32(7):828-836
Hydraulic conductance of leaves ( K leaf ) typically decreases with increasing water stress. However, the extent to which the decrease in K leaf is due to xylem cavitation, conduit deformation or changes in the extra-xylary pathway is unclear. We measured K leaf concurrently with ultrasonic acoustic emission (UAE) in dehydrating leaves of two vessel-bearing and two tracheid-bearing species to determine whether declining K leaf was associated with an accumulation of cavitation events. In addition, images of leaf internal structure were captured using cryo-scanning electron microscopy, which allowed detection of empty versus full and also deformed conduits. Overall, K leaf decreased as leaf water potentials ( Ψ L ) became more negative. Values of K leaf corresponding to bulk leaf turgor loss points ranged from 13 to 45% of their maximum. Additionally, Ψ L corresponding to a 50% loss in conductivity and 50% accumulated UAE ranged from −1.5 to −2.4 MPa and from −1.1 to −2.8 MPa, respectively, across species. Decreases in K leaf were closely associated with accumulated UAE and the percentage of empty conduits. The mean amplitude of UAEs was tightly correlated with mean conduit diameter ( R 2 = 0.94, P = 0.018). These results suggest that water stress-induced decreases in K leaf in these species are directly related to xylem embolism. 相似文献
17.
Determination of the surface area of fine tomato roots via cation uptake experiments 总被引:1,自引:0,他引:1
H. T. Wolterbeek 《Physiologia plantarum》1987,69(4):704-708
A method is described by which the surface area of a root is estimated from cation uptake data. 24 Na+ was supplied to excised roots of tomato ( Lycopersicon esculentum Mill, cv. Tiny Tim) seedlings at 3 μ M in unstirred solution. Coarse roots, for which external surface area and specific gravity could be measured accurately, were used to estimate the thickness (dN ) of the Nernst boundary layer at the root surface. 24 Na+ uptake (J1 ) was measured by γ-ray spectroscopy. Jt and dN were used to calculate the total surface area for ion absorption in fine roots, assuming that Na uptake rate was diffusion-limited. The results were compared to data obtained by conventional methods and indicated the usefulness of the cation uptake technique for quantitative estimates of root surfaces. 相似文献
18.
Changes in leaf hydraulics and stomatal conductance following drought stress and irrigation in Ceratonia siliqua (Carob tree) 总被引:1,自引:0,他引:1
Maria A. Lo Gullo rea Nardini Patrizia Trifilò Sebastiano Salleo 《Physiologia plantarum》2003,117(2):186-194
Changes in leaf hydraulic conductance (K) were measured using the vacuum chamber technique during dehydration and rehydration of potted plants of Ceratonia siliqua . K of whole, compound leaves as well as that of rachides and leaflets decreased by 20–30% at leaf water potentials (ΨL ) of −1.5 and −2.0 MPa, i.e. at ΨL values commonly recorded in field-growing plants of the species. Higher K losses (up to 50%) were measured for leaves at ΨL of −2.5 and −3.0 MPa, i.e. near or beyond the leaf turgor loss point. Leaves of plants rehydrated while in the dark for 30 min, 90 min and 12 h recovered from K loss with characteristic times and to extents inversely proportional to the initial water stress applied. Leaf conductance to water vapour of plants dehydrated to decreasing ΨL and rehydrated at low transpiration was inversely related to loss of K, thus suggesting that leaf vein embolism and refilling (and related changes in leaf hydraulics) may play a significant role in the stomatal response. 相似文献
19.
Michael Knee 《Physiologia plantarum》1995,95(2):211-216
I considered the possibility that changes in fruit photosynthesis obscure the occurrence of the climacteric rise in respiration in tomato fruits attached to the plant. Internal CO2 and ethylene concentrations in tomatoes ( Lycopersicon esculentum Mill. cv. OH 7814) were analyzed after direct sampling through polyethylene tubes implanted in the external pericarp. Fruits which were shaded with aluminium foil contained up to 60 ml 1−1 CO2 , until the internal ethylene concentration exceeded 1 μl l−1 , when CO2 concentration declined to below 40 ml l−1 ; the CO2 concentration in fruits exposed to light only occasionally exceeded 40 ml 1−1 . The internal CO2 concentration of detached fruits first declined and then increased along with ethylene concentration, as expected for the climacteric. Detached green fruits under continuous low photosynthetic photon flux density (100 μmol m−2 s−1 ) contained almost no internal CO2 and produced no CO2 . Changes in photosynthesis and an associated CO2 -generating system in green fruits are thought to obscure the climacteric rise in tomato fruits developing on the plant. 相似文献
20.
Fertilization of bean plants grown in perlite with 1 and 3 mM CaCl2 or Ca(NO3 )2 reduced severity of grey mould as compared with control plants or plants fertilized with 5 mM of the compounds. Fertilization with Ca(NO3 )2 reduced severity leaf grey mould and fruit ghost spots of tomato plants grown in perlite by 70 and 45%, respectively. The rate of decrease varied with the position of the fruits on the plants. Leaves from plants treated with calcium or otherwise [KNO3 , (NH4 )2 SO4 ] produced less ethylene than leaves of nontreated plants. Rate of growth of B. cinerea was lower on growth medium prepared from washings from leaves of calcium fertilized plants than from leaves from other treatments. The fertilizer combination Ca(H2 PO4 )2 + CaSO4 (1 and 3 g/kg soil) applied once to tomato plants grown in soil reduced severity of leaf grey mould by 80 % (significant at P = 0.05) but 1–3 g CaSO4 /kg soil only tended to reduce disease severity (30–40 %, not significant) as compared with the control. The compounds CaCl2 and Ca(NO3 )2 increased significantly ( P = 0.05) the growth of B. cinerea on synthetic medium when applied at rates of 1 0–10.0 mM whereas reduction of growth was observed with 0.1 mM of the compounds and of CaSO4 . 相似文献