Influence of Root and Content on the Temperature Response of Net and Uptake in Chilling Sensitive and Chilling Resistant Lycopersicon Taxa

We studied the influence of internal ammonium and nitrate contenton the temperature response of ammonium and nitrate uptake inboth chilling sensitive and chilling resistant tomatoes. Threetaxa were examined: Lycopersicon esculentum Mill. cv. T-5, achilling sensitive cultivar, Lycopersicon hirsutum Humb. andBompl. LA 1264, a wild, chilling sensitive accession from thelowlands of Ecuador, and Lycopersicon hirsutum LA1778, a chillingresistant accession from the highlands of Peru. Short exposures(4 h) of L. esculentum cv. T-5 to chilling temperatures irreversiblyinhibited ammonium absorption for at least 6 h. Nitrate absorptionin this taxon and ammonium and nitrate absorption in the L.hirsutum accessions recovered fully and immediately from suchexposures. The chilling resistant accession, L. hirsutum LA1778,showed a lower Q₁₀ for ammonium absorption (1?54?0?10, mean?s.e.)than its chilling sensitive relatives, L. hirsutum LA1264 (2?37?0?35)and L. esculentum cv. T-5 (1?92?0?11). The temperature responseof nitrate absorption depended on internal nitrate status; plantsgrown at high levels of ammonium and nitrate (200 mmol m^–3)showed higher Q₁₀'s for nitrate uptake (2?29?0?10) than thosedepleted of internal (1?86?0?12). Key words: Lycopersicon, ammonium, nitrate, temperature response, chilling     

Inhibition of Ethylene Production by Fatty Acids in Fruit and Vegetable Tissues

Fatty acids of chain length from C₄ to C₁₂ inhibited ethyleneproduction in wounded albedo tissue of Hassaku (Citrus hassakuHort. ex Tanaka) fruit. Of the fatty acids tested, caprylicacid (C₈) and capric acid (C₁₀) were the most effective. Lauricacid (C₁₂) was less effective, and caproic acid (C₆) and butyricacid (C₄) were the least effective. Caprylic acid at 5 mM markedlyinhibited ethylene production in not only wounded albedo tissueof citrus fruit but also apple (Malus sylvestris Mill.) cortex,tomato (Lycopersicon esculentum Mill.) pericarp, cucumber (Cucumissativus L.) cortex, banana (Musa AAA group Cavendish subgroup)pulp, broccoli (Brassica oleracea L.) floret, spinach (Spinaciaoleracea L.) leaf, lettuce (Lactuca sativa L.) leaf and mungbean (Vigna radiata [L.] Wilczek) hypocotyl. Caprylic acid inhibitedethylene production at the step of conversion of l-aminocyclopropane-l-carboxylicacid to ethylene. The inhibition could be partially relievedby transferring the tissue to caprylic acid-free medium. (Received June 15, 1982; Accepted August 13, 1982)     

Long-Term Chilling of Young Tomato Plants under Low Light. IV. Differential Responses of Chlorophyll Fluorescence Quenching Coefficients in Lycopersicon Species of Different Chilling Sensitivity

Temperature dependences of chlorophyll fluorescence quenchingcoefficients were studied in the cultivated tomato (Lycopersiconesculentum) and three lines of the chilling-tolerant L.peruvianumfrom different altitudes, i.e. LA 1373 (20 m a.s.l.), LA 2157(1,650 m a.s.l.) and LA 385 (2,400 m a.s.l.). At actinic lightintensity near light saturation of photosynthesis (370 µEm^–2 s^7minus;1), photochemical quenching (qP) increasedwith increasing temperature between 5 and 30°C. The temperature,at which qP reached the numerical value 0.5 [T (qP=0.5)] decreasedby 2.5–4.5°C after a chilling treatment of 14 daysat 10°C in L. peruvianum, indicating acclimation of thephotosynthetic dark reactions in this species. The final T (qP=0.5)attained after chilling could be arranged in the order L.esculentum>LA1373>LA 2157>LA 385. The fast relaxing non-photochemicalquenching (qN) component (qf, consisting mainly of energy-dependentquenching, qE) exhibited minima near the optimum temperaturefor photosynthesis. These minima shifted to lower temperaturesupon chilling in L. peruvianum. Photoinhibitory quenching (ql)was unaffected by chilling in the high altitude lines, but-increasedstrongly in LA 1373 and L. esculentum. Under low actinic light(40 µE m^–2 s^–1), temperature dependences ofqP and qN were nearly identical in L. esculentum and LA 385and revealed abrupt changes at approx. 8°C. It is concludedthat qP and ql, measured after defined chilling treatments,are valuable screening parameters for chilling tolerance inearly growth stages of Lycopersicon plants. (Received November 2, 1993; Accepted February 28, 1994)     

Quantal Response of Seed Germination in Seven Genera of Cruciferae to White Light of Varying Photon Flux Density and Photoperiod

The response of the germination of seeds of Barbarea vema (Mill.)Aschers, Brassica chinensis L., Brassica juncea (L.) Czern.& Coss., Brassica oleracea L. var. gongylodes L., Camelinasaliva (L.) Crantz, Eruca saliva Mill., Lepidium sativum L.,Nasturtium officinale R. Br., and Rorippa palustris (L.) Besserto white fluorescent light of different photon flux densitiesapplied for different daily durations in a diurnal alternatingtemperature regime of 20 °C/30 °C (16 h/8 h) was quantifiedby linear relations between probit percentage germination andthe logarithm of photon dose, the product of photon flux densityand duration. The low energy reaction, in which increasing dosepromotes germination, was detected in all the seed populationsbut in Barbarea vema and Brassica Juncea the lowest photon doseapplied (10^–5–2 and 10^{–5 7} mol m^–2 d^–1,respectively) was sufficient to saturate the response. Comparisons,where possible, between photoperiods demonstrated reciprocity,i.e. germination was proportional to photon dose irrespectiveof photoperiod, for the low energy reaction in Brassica oleracea(1 min d^–1 to 1 h d^–1), Camelina saliva (1 min d^–1to 8 h d^–1), Eruca saliva (1 min d^–1 to 24 h d^–1),Lepidium sativum (I min d^–1 to 8 h d^–1) and Rorippapalustris (1 min d^–1 to 8 h d^–1), but not in Brassicachinensis and Nasturtium officinale. The high irradiance reaction,in which increasing dose inhibits germination, was detectedin Barbarea vema, Brassica chinensis, Brassica juncea, Brassicaoleracea, and Camelina saliva. The minimum dose at which inhibitionwas detected was lO^–0–3 mol m^–2 d^–1.These results are discussed in the context of devising optimallight regimes for laboratory tests intended to maximize germination The response of germination to photon dose was also quantifiedwith 3 x 10^–4 M GA₂, co-applied (Brassica chinensis, Camelinasaliva, and Lepidium sativum) and with 2 x 10^–2 M potassiumnitrate co-applied (Brassica chinensis). In the latter casepotassium nitrate had no effect in the dark and inhibited germinationin the light, but GA₂, promoted germination substantially inall three species. Variation amongst seeds in the minimum photondose required to stimulate germination was not affected by co-applicationof GA₂, in Brassica chinensis and Camelina saliva, whereas seedsof Lepidium salivum showed a narrower distribution of sensitivitiesto the low energy reaction in the presence of GA₂ Barbarea vema (Mill.) Aschers, Brassica chinensis L., Brassica juncea (L.) Czern. & Coss., Brassica oleracea L. var. gongylodes L., Camelina saliva (L.) Crantz, Eruca saliva Mill., Lepidium satiaum L., Nasturtium officinale R. Br., Rorippa palustris (L.) Besser, Cruciferae, light, gibberellic acid, seed germination, seed dormancy     

Pressure -Flow Relationships, Xylem Solutes and Root Hydraulic Conductance in Flooded Tomato Plants

Roots of month-old tomato plants (Lycopersicon esculentumMill.)were flooded for up to 36h. Shoots were removed just below thecotyledonary node, and the roots subjected to external pneumaticpressures (     

Stimulation of the Uptake of Sorbitol into Vacuoles from Apple Fruit Flesh by Abscisic Add and into Protoplasts by Indoleacetic Acid

The uptake of sorbitol into vacuoles from immature flesh ofapple fruit (Maluspumila Mill, var domestica Schneid.) was facilitatedby 10^–6 M ABA, while such uptake into protoplasts wasnot stimulated. By contrast, the application of 10^–5 MIAA facilitated uptake of sorbitol into protoplasts but didnot significantly into vacuoles. (Received July 17, 1990; Accepted December 25, 1990)     

Morphogenetic Aspects of a Leafless Mutant in Tomato: III. GROWTH AND PEROXIDASE ACTIVITY OF ROOTS

Using morphological and biochemical criteria, comparisons weremade between intact and excised roots of normal tomato (Lycopersiconesculentum Mill.) and the reduced form of the homozygous lanceolatemutant. Intact normal roots showed greater growth as reflectedin length of the main root axis, number of lateral roots, andprotodermal cell size. Excised normal roots grew more rapidlythan those of the mutant only during the first 24-h intervalof the first week in culture. Intact mutant roots revealed agreater activity of peroxidase, but excised mutant roots showedno increase in enzyme activity. It is concluded that the primarysite of action of the mutant allele is the shoot system, andin particular the leaf marginal meristem. The effects of thelanceolate gene on the root system in tomato are interpretedas being of secondary importance with regard to gene action.     

Effects of Heat Stress on Carbon Transport from Tomato Leaves

Export of radioactive carbon from two cultivars of tomato, (Lycopersiconesculentum Mill.) leaves was inhibited in response to heat stress.Increasing temperatures resulted in a marked decrease in leafstarch levels. The depletion of starch concentration in theleaves was primarily due to hydrolysis and an inhibition ofstarch formation. At high temperatures, starch hydrolysis wasinhibited in Roma VF, a heat sensitive cultivar, while Saladette,a heat tolerant cultivar was not similarly affected. Calloseformation was found on phloem sieve tube plates of leaf petiolesexposed to 72 h of high temperatures. More sieve tube plateswere covered with a thicker callose layer in Roma VF than inSaladette. Lycopersicon esculentum (Mill.), tomato, carbon translocation, starch hydrolysis, callose, heat stress     

Structure and expression of a cDNA encoding a putative neoxanthin cleavage enzyme (NCE), isolated from a wilt-related tomato (Lycopersicon esculentum Mill.) library

Oxidative cleavage of a 9-cis xanthophyll probably representsthe key regulatory step in abscisic acid (ABA) biosynthesis.A transposon tagged maize (Zea mays) mutant vp14, provided theoriginal DNA sequence data needed to design a VP14 fusion proteincapable of catalysing this reaction in vitro. A cDNA encodinga similar protein has now been isolated from a wilt-relatedtomato (Lycopersicon esculentum Mill.) library. The tomato cDNAand derived amino acid sequence have been compared to thoseof maize and of other enzymes catalysing broadly similar oxidativecleavage reactions. The results of Northern analysis in tomatoindicated that mRNA levels of this vp14 homologue increaseddramatically in response to water stress. Key words: ABA biosynthesis, oxidative cleavage step, tomato     

Periods of Shoot Chilling Sensitivity in Soybean Flower Development, and Compensation in Yield after Chilling

Soybeans [Glycine max (L.) Merr. cv. Ransom] grown at a constant25 °C were placed in a 12-h inductive photoperiod at twoweeks of age. Subgroups were shoot-chilled for one week at aconstant 10 °C during each of the first four weeks of floralinduction. Controls were photoinduced but not chilled. Chillingduring the first week of photoinduction inhibited productionof floral primordia, but did not increase the abscission rateof flowers and pods. Chilling during the second week did notaffect primordium production or abscission rate, but did causea significant increase in numbers of fused and malformed pods.Chilling during the third week caused loss of 77 per cent ofearly flowers and pods by abscission, while fourth week chillingcaused less severe losses by abscission. Inhibition of vegetativegrowth may have been responsible for primordium loss in first-weekplants, while disturbances in the development of flowers wereresponsible for the losses in the other chilling weeks. Althoughchilling during the first and third photoinduction weeks causeda significant reduction in early pod numbers, plants harvestedat 16 weeks of age showed no significant loss in seed yield.Low abscission rates late in pod filling and increased weightof individual seeds compensated for early losses of pods. Thesecompensatory responses to a chilling-induced loss of pods aresimilar to those reported for mechanically depodded soybeans. Glycine max (L.) Merr., soybean, temperature, chilling, floral initiation, anthesis, abscission, yield, compensation     

Effects of Leaf Age and Position on the Shoot Axis on Potassium Absorption by Tomato Leaf Slices

The effect of leaf age on K (⁸⁶Rb) influx into tomato (Lycopersiconesculentum Mill.) leaf lamina slices was determined for leaves5, 9 and 13 counting acropetally. Potassium influx rates expressedon a leaf fresh weight basis declined rapidly during leaf elongationat external KCI concentrations between 0.5 and 20.0 mM. In fullyexpanded leaves, K influx rates declined more slowly with age.The onset of senescence in mature leaves did not result in alarge loss in K uptake capability. Leaf position on the shootaxis and the stage of whole plant development had little influenceon K influx into leaf cells. It is suggested that the rapiddecrease in K influx in growing leaves is related to a dilutionin the concentration of K transporter sites resulting from anincrease in cell volume and weight. Lycopersicon esculentum Mill, tomato, free space, potassium, influx rate, ion uptake, leaf slices, leaf age leaf ontogeny     

Thigmomorphogenesis: the Effect of Mechanical Perturbation and Ethrel on Stem Pithiness in Tomato [Lycopersicon esculentum (Mill.) Plants]

The stems of ‘Y’-shaped (double stemmed) tomato(Lycopersicon esculentum Mill.) plants were mechanically perturbed(MP) by stroking for 6 successive days. The treatment reducedelongation of the two stems by 40 per cent. When only one branchof the pair was treated, its length was reduced to the sameextent as the two branches in the previous treatment, whilethe elongation of the untreated branch was increased by 60 percent over that of the control. Withholding irrigation induced stem pithiness due to droughtstress in non-MP-plants. However, in MP-pretreated plants, thenumber of pithy internodes was markedly less and the degreeof severity of the disorder was reduced. Ethrel applicationmimicked the effects of MP on pithiness. In some unknown way,the plants are hardened by MP or Ethrel. Lycopersicon esculentum Mill, tomato, drought stress, thigmomorphogenesis, ethylene, pithiness     

Effect of Heat Stress on Assimilate Metabolism in Tomato Flower Buds

Assimilate import by flower buds in two cultivars of tomato(Lycopersicon esculentum Mill.) was inhibited by heat stress.With increasing temperature, levels of sucrose in the sourceorgan increased while levels of starch decreased. The transportof radioactive carbon was correlated with the starch contentof the flower buds. In Saladette, a heat-tolerant cultivar,conversion of the imported carbon to starch occurred to a greaterextent than in Roma VF, a heat-sensitive cultivar. Uptake ofsucrose from agar medium by detached flower buds was negativelycorrelated with their internal ratio of sucrose to hexoses.Glucose uptake from agar medium by detached flower buds decreasedwith increasing temperatures. Sucrose hydrolysis was negativelyaffected by high temperatures, and this was more pronouncedin the heat-sensitive than in the heat-tolerant cultivar. Theeffect of heat stress on assimilate translocation from the leavesto the sink organ is discussed. Lycopersicon esculentum Mill., starch, sucrose, heat stress     

Recovery after Chilling: An Assessment of Chill-Tolerance in Phaseolus spp.

Guye, M. G, Vigh, L. and Wilson, J. M. 1987. Recovery afterchilling: an assessment of chill-tolerance in Phaseolus spp.—J.exp. BoL, 38: 691–701. The chill-sensitivity of three Phaseolus spp. (eight cultivars)was assessed by measuring five different physiological parameters(leaf pigment loss, leaf diffusion resistance, relative growthrate recovery, change in leaf water content and the severityof leaf necrosis) on return to the warmth (23 ?C/18 ?C) followinga brief but severe chilling treatment (24 h at 5 ?C). In thisway the genotypes could be ranked in order of increasing chill-sensitivityas follows: P. coccineus cvs Prizewinner and Streamline, P.vulgaris cv. 251 < P. vulgaris cvs 194, 222 and Seafarer< P. vulgaris cv. Tendergreen < P. aweus cv. Berken. Key words: Chill-tolerance ranking, chlorophyll, leaf diffusion resistance, leaf water content, growth rate, carotenoid, Phaseolus     

A Persisting Cellulosic Wall of Microspore Mother Cells during Microsporogenesis in Allium tuberosum Rottl. and Cyclamen persicum Mill

Light microscopic studies were carried out on the anthers ofAllium tuberosum Rottl. and Cyclamen persicum Mill. Callosedeposition is initiated within the primary wall round each microsporemother cell during early prophase of meiosis I and is of maximumthickness at the tetrad stage. The original cellulosic wall,contrary to earlier reports for other species, persists aroundthe microspore mother cells until the late tetrad stage in bothspecies. In C. persicum, it dissolves to release the callose-encasedtetrads, and in A. tuberosum, il dissolves simultaneously withcallose at the time of release of microspores. Allium tuberosum Rottl., Cyclamen persicum Mill., microsporogenesis, microspore mother cell     

Ethylene Production by Fe-deficient Roots and its Involvement in the Regulation of Fe-deficiency Stress Responses by Strategy I Plants

Species that showed marked morphological and physiological responsesby their roots to Fe-deficiency (Strategy I plants) were comparedwith others that do not exhibit these responses (Strategy IIplants). Roots from Fe-deficient cucumber (Cucumis sativusL.‘Ashley’), tomato (Lycopersicon esculentumMill.T3238FER) and pea (Pisum sativumL. ‘Sparkle’) plantsproduced more ethylene than those of Fe-sufficient plants. Thehigher production of ethylene in Fe-deficient cucumber and peaplants occurred before Fe-deficient plants showed chlorosissymptoms and was parallel to the occurrence of Fe-deficiencystress responses. The addition of either the ethylene precursorACC, 1-aminocyclopropane-1-carboxylic acid, or the ethylenereleasing substance, Ethephon, to several Fe-sufficient StrategyI plants [cucumber, tomato, pea, sugar beet (Beta vulgarisL.),Arabidopsis(Arabidopsis thaliana(L.) Heynh ‘Columbia’), plantago(Plantago lanceolataL.)] promoted some of their Fe-deficiencystress responses: enhanced root ferric-reducing capacity andswollen root tips. By contrast, Fe-deficient roots from severalStrategy II plants [maize (Zea maysL. ‘Funo’), wheat(Triticum aestivumL. ‘Yécora’), barley (HordeumvulgareL. ‘Barbarrosa’)] did not produce more ethylenethan the Fe-sufficient ones. Furthermore, ACC had no effecton the reducing capacity of these Strategy II plants and, exceptin barley, did not promote swelling of root tips. In conclusion,results suggest that ethylene is involved in the regulationof Fe-deficiency stress responses by Strategy I plants.Copyright1999 Annals of Botany Company. Arabidopsis (Arabidopsis thaliana(L.) Heynch), barley (Hordeum vulgareL.), cucumber (Cucumis sativusL.), ethylene, iron deficiency, maize (Zea maysL.), pea (Pisum sativumL.), plantago (Plantago lanceolataL.), ferric-reducing capacity, sugar beet (Beta vulgarisL.), tomato (Lycopersicon esculentumMill.), wheat (Triticum aestivumL.).     

Effects of Leaf Chilling on Thylakoid Functions, Measured at Room Temperature, in Cucumis sativus L. and Oryza sativa L.

Photosynthetic functions in leaves of cucumber (Cucumis sativusL.) and rice (Oryza sativa L.) were examined before and aftervarious chilling treatments. Cucumber leaves lost the capacityfor the photosynthetic oxygen evolution after chilling at 0°Cin the dark for 48 h. Thyla-koids isolated from such leaveswere not able to reduce dichloroindophenol (DCIP), but the additionof diphenylcarbazide (DPC), an electron donor to PS II, restoredthe ability to reduce DCIP, indicating that the site of damageis in the water-splitting machinery of PS II. In moderate light (500 jumol quanta m^–2s^–1), chillingof cucumber leaves at 5°C for 5 h was sufficient to inducethe complete loss of the capacity for photosynthetic oxygenevolution. Electron transport rates measured in thylakoids wereunaltered, but thylakoids were totally permeable to protons.Since the addition of dicyclohexylcarbodiimide (DCCD) restoredcoupling and the capacity for proton uptake, the primary siteof damage was deduced to be in the ATPase. In rice, both chilling treatments had barely any effect on thylakoidfunctions, although some negative effects was apparent in photosynthesisin leaves. ¹Present address: Department of Botany, Faculty of Science,University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113 Japan. ²Present address: Department of Botany, Duke University, Durham,NC 27706, U.S.A. (Received January 11, 1989; Accepted June 12, 1989)     

Germination Inhibitors in some Umbellifer Seeds

Presence of inhibitors of germination in seeds of five umbellifercrops viz. fennel (Foeniculum vulgare Mill.), cumin (Cuminumcyminum L.), carum (Carum copticum Benth. and Hook.), carrot(Daucus carota L.), and coriander (Coriandrum sativum L.) wasdemonstrated. The effect of seed exudates on the pattern ofinhibition of germination of these seeds was also studied. Presence of exudates in general delayed germination althoughthe time of maximum inhibition was different with differentcrop seeds. The inhibitory effect was high at an early stagein the case of carum and carrot and persisted in the latterbut disappeared in the former. The inhibitory effect on cuminand fennel increased up to the seventh day and then began todecrease. Growth of root and hypocotyl of 16-day-old seedlingswas also inhibited by the exudates.     

Canopy Photosynthesis of Tomato, Cucumber and Sweet Pepper in Greenhouses: Measurements Compared to Models

Two models for canopy photosynthesis (modified versions of thoseof Acock et al. , 1978 and of Thornley, 1976) were examinedby comparison with experimental photosynthesis data of cucumber(Cucumis sativus L.), sweet pepper (Capsicum annuum L.) andtomato (Lycopersicon esculentum Mill.). The data were obtainedin six large-scale, long-term, semi-commercial cultivationsin greenhouses (Nederhoff and Vegter, 1994). Measured environmentalconditions and measured LAI were input to the model. The emphasiswas on the models' sensitivity to the prevailing CO₂ concentration. The (modified) Acock model with 'standard' (originally published)parameters underestimated the photosynthesis rate. This modeltuned to one of our experimental data sets did not fit verywell to the other data sets. As expected, if the model was tunedto each particular data set, it was fairly in agreement withthe measurements, but the fitted parameter values were sometimesquestionable. With the (modified) Thornley model it was obligatoryto estimate or tune the light extinction. The model performedreasonably if all parameters were tuned and also if only thelight extinction was tuned. The modified models were considered usable for practical applications,after parameter tuning. As the sensitivity to CO₂ was not alwaysequal among the models and the measurements, care should betaken when applying the models for CO₂ supply control.Copyright1994, 1999 Academic Press Canopy photosynthesis, Capsicum annuum L., carbon dioxide, cucumber, CO₂, Cucumis sativus L., glasshouse, greenhouse, Lycopersicon esculentum Mill., measurements, model, sweet pepper, tomato     

Role of Ethylene in Avocado Fruit Development and Ripening: II. ETHYLENE PRODUCTION AND RESPIRATION BY HARVESTED FRUITS

Avocado (Persea americana Mill.) fruits were harvested at successivedevelopment stages during a period of 10 months. Ethylene productionand respiration were determined during the post-harvest period. Detached immature fruits were found to have a preclimactericincrease in ethylene production and respiration without anysigns of ripening. In fruits larger than 20 g a second phaseof climacteric ethylene production and respiration, associatedwith ripening, ensued. The preclimacteric ethylene was produced mainly by the seedcoat. It is suggested that the high ethylene production potentialof the seed coat may serve as a means for inducing abscissionin young fruits.