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1.
This experiment was conducted to study the effect of salicylic acid addition to nutrient solution and different postharvest treatments on fruit quality of strawberry cv. Camarosa after 7 days at 2 °C. Plants were irrigated with two complete nutrient solutions, with salicylic acid (0.03 mM) or without salicylic acid as the control. Fruits were then treated with eight different postharvest treatments (25 °C water, 45 °C water, 25 °C or 45 °C water containing CaCl2 (1%), 25 °C or 45 °C water containing salicylic acid (2 mM) and 25 °C or 45 °C water containing both CaCl2 (1%) and salicylic acid (2 mM)). Fruits which received SA in their nutrient solution had less weight loss and decay and higher firmness. All of the postharvest treatments improved fruit quality characteristics. Fruits dipped in salicylic acid solution had less weight loss, decay and a* (redness) and higher firmness and hue angle than control. Heat treated fruits had less decay and a* and higher hue angle than control. Fruits dipped in CaCl2 solution had less weight loss, decay and a* and higher firmness than control. Combination of the three postharvest treatments improved firmness, decay, weight loss and vitamin C.  相似文献   

2.
The aim of this study was to evaluate the effects of low molecular mass antioxidants and NaCl salinity on growth, ionic balance, proline, and water contents of ‘Zard’ olive trees under controlled greenhouse conditions. The experiment was carried out by spraying 2 mM of ascorbic acid (Asc) and 3 mM of reduced glutathione (GSH) on the plants that were treated with two salinity levels (0 and 100 mM NaCl) on their root medium. Plant growth parameters (leaf fresh weight, leaf dry weight, leaf number, total fresh weight, and total dry weight) were significantly improved by Asc compared with growth parameters in GSH and control plants. Higher concentrations of Na+ and Cl– were observed in salt-stressed plants, while Na+ and Cl– concentrations were decreased in the olive leaves that were sprayed with Asc. Salinity in the root zone caused a considerable decline in both K+ concentration and K/Na ratio. K+ concentration and K/Na ratio were significantly increased by application of Asc on plant leaves. Salinity caused an increase in electrolyte leakage (EL) compared with the control plants. Lowest EL and tissue water content (TWC) was obtained in Asc-sprayed plants, whereas TWC was increased in salt-stressed plants. Plants were subjected to salt stress and showed a higher relative water content (RWC) than the control plants. Salt stress induced proline accumulation in olive leaves. In conclusion, exogenous application of Asc is recommended to improve tolerance of olive plants under saline conditions.  相似文献   

3.
Factors affecting adventitious root formation were studied in isolated stem segments of three Rhododendron cultivars, ‘Catawbiense Album’, ‘Pink Pearl’ and ‘Van Weerden Poelman’, having different rooting ability. The experiments consisted of varying certain factors, while keeping the others constant.Root formation was always less in ‘Van Weerden Poelman’ than in the easy-to-root cultivars. Rooting usually occurred only in segments from young soft shoots. The length of the explants did not affect rhizogenesis. Removal of a strip of bark promoted adventitious root formation. Oxygen supply appeared to be essential since only inverted segments were capable of forming roots. Darkness was essential for rooting. The optimum temperature was 25°C. Root formation occurred only when a sugar was present in the medium. Rooting decreased with increasing osmotic pressure. Macroelements, boric acid and the pH of the medium did not play an essential role. Auxin was an absolute requirement for rooting, the kind and concentration depending on the cultivar used. Benzylamino purine at low concentrations increased root dry weight. GA3 and abscisic acid decreased rooting.  相似文献   

4.
Summary

Experiments were conducted to optimize nutritional and cultural requirements for initiation and growth of roots on papaya in vitro. Axillary shoots were obtained from plants which had been sub-cultured monthly for two years. Root initiation was enhanced when 1 to 2 mm of stem base was removed and shoots were growing actively before transfer to the rooting medium. Decreasing daylength during incubation from 24 h to 12 h promoted root initiation. Within the day temperature range of 22 to 29°C, optimum rooting occurred at 27°C and higher temperatures produced higher mean root weights per shoot. High concentrations of growth factors and the absence of sucrose in the medium both reduced root initiation, however, varying the concentration of sucrose and removing growth factors affected mean root weight per shoot. All media contained a modified de Fossard et al. (1974) basal medium plus 10 μM IBA.  相似文献   

5.
负水头供不同营养液对温室樱桃番茄生长和产量的影响   总被引：2，自引：0，他引：2  
采用负水头灌溉装置,通过调节装置的供水吸力值来持续稳定地控制栽培基质的湿度,供给不同浓度磷酸二氢钾（KH2PO4）营养液配方进行樱桃番茄基质栽培试验,研究营养液中不同磷酸二氢钾浓度对樱桃番茄株高、茎粗、产量、水肥利用效率和根系活力的影响。结果表明：在负水头供水控水技术条件下,适当提高营养液中磷酸二氢钾浓度,有利于增加樱桃番茄株高、茎粗,效果显著;同时可以提高果实产量、水分利用效率和N、K利用效率以及根系活力。负水头供给营养液樱桃番茄栽培生产中,2.5 S处理即340 mg•L-1的KH2PO4浓度可作为推荐用量。  相似文献   

6.
《Scientia Horticulturae》2001,89(3):217-226
Single node cuttings with one mature leaf were taken from the rose cv. Baroness and rooted in water culture. The rooted stems were kept in water culture and subjected to one of the two levels of relative air humidity (RH) (high: 90%, moderate: 70%) in climate chambers. Morphological characteristics, dry weight (DW), osmotic concentration, hemicellulose, cellulose and lignin content in the pedicel and vase life behavior were studied, as well as water loss. Only negligible differences in growth and morphology were found. No clear difference in lignin, hemicellulose and cellulose content in pedicels was found between moderate and high RH grown roses. Uncontrolled water loss was characteristic for leaves from high RH roses. Base treatment with AgNO3 improved vase life of high RH roses from 7 to 12 days. Moderate RH roses lasted on average 15.5 days, and vase life was only slightly improved with the use of AgNO3. Preservative solutions caused crispy areas between the veins and brittle leaves on roses grown at high but not at moderate RH. A 10% lower osmotic concentration in leaves and flowers was found in roses grown at high RH, as compared to moderate RH. It is concluded that the shorter postharvest life of high RH flowers is mainly due to malfunctioning stomata.  相似文献   

7.
Summary

Severe desiccation of dormant seedlings of wild cherry (Prunus avium) and cherry plum (P. cerasifera) did not affect their immediate survival, but caused significant reductions in subsequent shoot growth and root volume which were not recovered in a single growing season. Damage to the fine roots, as indicated by the physiological plant quality measures of tetrazolium absorbance and root electrolyte leakage, increased rapidly over drying periods of ca. 6 h, further damage requiring progressively longer periods of desiccation. Root pruning prior to planting did not mitigate desiccation damage and severe pruning was highly injurious to subsequent growth. Generally the removal of the fine roots was equivalent to a relatively short desiccation period, but pruning of fine roots prior to, instead of after, desiccation in P. cerasifera resulted in more lateral shoots, possibly indicating the production of growth retardant substances by the dried root systems. All measures of physiological plant quality at the beginning of the growing season were effective as predictors of plant performance at the end. In the species tested, the most cost-effective routines are likely to be fine root electrolyte leakage and root moisture content, with tetrazolium testing and stem water potential measurements requiring both greater reproducibility and more sophisticated equipment.  相似文献   

8.
Changes in mineral nutrient concentration, growth, water status and gas exchange parameters were investigated in young banana plants (Musa acuminata cv. ‘Grand Nain’) subjected to gradual soil moisture diminution. Experiments were performed in glasshouse under controlled temperature, and water stress was imposed by ceasing irrigation for 62 days. The data showed a parallel decrease of leaf gas exchange parameters and soil moisture initiated few days after the imposition of water stress. However, the leaf relative water content (RWC) showed a minor decrease in response to drought. The onset of growth reduction evaluated as plant height, pseudostem circumference, number of newly emerged leaves, leaf area, and leaf and root biomass took place approximately between 34 and 40 days after the beginning of the stress period. In addition, drought did not modify nitrogen and phosphorus concentrations in foliar and root tissues; however, it increased potassium, calcium, magnesium, sodium and chloride in leaves, and only calcium, sodium and chloride in roots. Collectively, the data reveal that banana plants show a drought avoidance mechanism in response to water stress. After a prolonged drought period, leaf RWC was hardly reduced, while gas exchange and growth parameters were reduced drastically. Increasing leaf mineral concentration could have help to maintain leaf RWC due to osmotic adjustment mechanism.  相似文献   

9.
Olive (Olea europaea L.) is the major fruit tree in the Mediterranean region, often grown in locations where plants are exposed to increased salinity. To determine the effect of NaCl on shoot and root growth, dry matter allocation, leaf Na+ and K+ concentration, electrolyte (EL) and K+ leakage (KL), seven olive cultivars of different origins were grown in nutrient solution containing 0, 33, 66, 100 or 166 mM NaCl for three months. The general effect of salinity was linear and quadratic decrease of observed plant growth parameters. Different responses of tested cultivars to applied levels of salinity were found for stem dry weight, shoot length and number of leaves. As salinity increased, growth of ‘Manzanillo’ declined sharply, whereas ‘Frantoio’ was the most tolerant to growth reduction in most of the observed growth parameters. Allometric analysis showed that biomass allocation under salinity stress was similar in all cultivars, but the slope between shoot weight and total plant weight decreased as salinity increased. Since the higher allocation in roots was not found, it seems that salinity only slowed the above ground plant canopy growth. Sodium concentration in leaves of all cultivars increased as salinity increased with the highest increment reached when the salinity of nutrient solution was raised from 100 to 166 mM NaCl. Significant differences among genotypes were found in leaf Na+ and K+ concentration and K+:Na+ ratio, but they were not related to the growth rate. Generally, ‘Frantoio’ and ‘Oblica’ accumulated less Na+ and were able to maintain higher K+:Na+ ratios as compared to other genotypes. Electrolyte leakage and KL linearly increased with increasing salinity and the magnitude of the response depended upon the olive cultivar.  相似文献   

10.
Single node cuttings with one mature leaf were taken from the rose cv. Baroness and rooted in water culture. The rooted plants were grown in nutrient solutions and subjected to two levels of relative air humidity (RH): high (90%) and moderate (70%), in combination with high (12/1), medium (1/1) and low (1/5) K/Ca ratios in the nutrient solution. High RH plants accumulated less Ca in leaves and flowers than moderate RH plants. Roses grown at moderate RH had a longer postharvest life than high RH roses, irrespective of the K/Ca ratio of the nutrient solution. In general, a high K/Ca ratio had a negative impact on postharvest life. When grown at a high K/Ca ratio the ornamental value declined rapidly, mainly due to the appearance of necrotic petals as well as chlorotic and necrotic areas on the leaves. Bent neck occurred only with high RH plants but changes in the K/Ca ratio had no differential effect. Dry spots and brittle leaves were observed on high RH roses, and the occurrence increased with increased K/Ca ratio in the nutrient solution. Stomatal conductance increased in parallel with increases in RH and K/Ca ratio when measured on intact roses placed in dry air (40% RH).  相似文献   

11.
根系限制对酿酒葡萄生长发育的影响   总被引：12，自引：0，他引：12  
 用10、20 和50 L 容积的塑料盆盆栽酿酒葡萄, 探讨了根系生长范围对地上和地下部生长的影响。各处理的根干物量由小到大依次为: 10、20、50 L。50 L 处理根量分别是20L 和10 L 的1. 78 倍和3. 38 倍。按直径将根分为粗根( > 3 mm) 、中级根(0. 5 ～3. 0 mm) 、细根( < 0. 5 mm) , 限根处理使细根量显著增加。同级根平均根长和根重无显著差别, 表明限根后根重减少是根数量减少之故, 而非根变短变细。地上部生长受限根处理影响显著, 干物量、叶质量、叶面积均显著降低。  相似文献   

12.
Root restriction often depresses photosynthetic capacity and the mechanism for this reduction, however, remains unclear. To identify the mechanism by which root restriction affects the photosynthetic characteristics, tomato (Lycopersicon esculentum Mill.) seedlings were subjected to root restriction stress with or without supplemental aeration to the nutrient solution. With the development of the root restriction stress, CO2 assimilation rate was decreased only in confined plants without supplemental aeration. There were also significant decreases in leaf water potential, stomatal conductance (gs), intercellular CO2 concentration (Ci), and increases in the stomatal limitation (l) and the xylem sap ABA concentration. Meanwhile, the maximum carboxylation rate of Rubisco (Vcmax) and the capacity for ribulose-1,5-bisphosphate regeneration (Jmax) also decreased, followed by substantial reductions in the quantum yield of PSII electron transport (ΦPSII). Additionally, root restriction resulted in accumulation of carbohydrates in various plant tissues irrespective of aeration conditions. It is likely that root restriction-induced depression of photosynthesis was mimicked by water stress.  相似文献   

13.
Summary

The effect of different doses of nitrogen on water stress in tomato (Lycopersicon esculentum Mill. ‘Royesta’) plants grown in a sandy soil and exposed, or not, to long-term water stress was studied. Nitrogen dose treatments consisted of Hoagland’s solution (N1 treatment), Hoagland’s solution + 40 mM NO3– (N2 treatment), or Hoagland’s solution + 80 mM NO3– (N3 treatment) applied every 3 d, for a total of seven applications following plant establishment. Subsequently, daily application of 80% (stressed) or 100% (unstressed) of the water evapotranspired by control plants the previous day was combined, factorially, with the three nitrogen treatments, for a period of 2 weeks. The leaf fresh weight (FW) at full turgor:leaf dry weight (DW) ratio was high in plants under the N1 and N3 stress treatments, with no significant difference between them soon after the start and at the end of the water stress treatment. However, the N2 treatment produced a significant increase in the ratio in well-watered plants, but not in water-stressed plants at the end of the stress period. The surface area per leaf was greater in stressed than in control plants, except for N2. Leaf water potential was greatly reduced in stressed N2 and N3 plants, but was unaltered in their well-watered counterparts. The significant increases in relative water content at the turgor loss point (around 3%) and in cell membrane rigidity (an increase of more than 125% in the bulk modulus of elasticity) clearly indicate an osmotic adjustment in stressed N2 plants, confirming that this N dose moderated the effects of the water stress imposed on N2 plants.  相似文献   

14.
Summary

The content of ammonium, nitrate and potassium was varied in the macronutrient solutions intended for formation of adventitious shoots from petiole expiants of Senecio × hybridus. The other components of the macronutrients were according to Murashige and Skoog (1962). The largest number of expiants which formed shoots was obtained when the nitrogen concentration in the Murashige-Skoog solution was lowered from 60 to 30 mM and the potassium concentration from 20 to 15 mM. Addition of 1.0 μM TIBA to the medium as well as the standard addition of 4.44 μM BAP and 28.5 μM IAA favoured shoot formation. Even growth in darkness for two weeks immediately after expiant excision increased shoot number. The nitrogen content in the tissue decreased as the nitrogen concentration in the medium decreased, although an increased concentration in the medium from 60 to 75 mM did not increase the nitrogen content in the tissue. When the potassium concentration was changed from 20 to 15 mM, in a medium with 30 mM nitrogen, the nitrogen concentration in the tissue increased. On the other hand, when using a medium with 60 mM nitrogen, the potassium concentration (30 and 20 mM) did not affect the nitrogen content of the tissue.  相似文献   

15.
Abstract

BA 29 and EMA (Cydonia oblonga L.) plants were grown in a 1:1 sand:perlite mixture and irrigated with nutrient solutions containing two B concentrations (0.025 and 0.2 mM) combined with two salinity (electrical conductivity, EC) levels (0.75 and 4 dS-m-1). The lowest growth of plants was recorded when 0.2 mM B was combined with 4 dS-m-1 in the nutrient solution. As salinity (EC) level increased from 0.75 to 4 dS-m-1, P, Ca and Fe concentrations of leaves decreased. The potassium concentration of leaves of both rootstocks increased, as salinity levels (induced by KCl) increased. The two quince genotypes respond differently for the same treatments, indicating a genotypic effect.  相似文献   

16.
Abstract

Fruit yield and nutrient concentration of mango (Mangifera indica L.) cultivar ‘Osteen’ were studied in relation to rootstocks Gomera-1 and Gomera-3 for three years. The results indicated that the Gomera-3 root system had higher nutrient uptake and transport towards the scion. Data from grafted and ungrafted Gomera-1 and Gomera-3 trees proved similar with respect to N, P, and K utilization profile, with post-harvest accumulation and a decline during flowering, P and K concentrations significantly decreasing during fruit growth. These trends were largely the opposite for Ca and Mg. The Fe, Zn, Mn, and Cu concentrations rose during dormancy and fell at flowering. Fruit yield was higher with Gomera-1, while Gomera-3 gave fruit with greater weight and width. Tree height, trunk cross-sectional area, canopy diameter and volume were greater in grafted and ungrafted Gomera-3, this rootstock being the most vigorous. The yield efficiency was significantly greater on Gomera-1. Thus, cv. ‘Osteen’ grafted to Gomera-1 offered better yield and required a lower amount of nutrients.  相似文献   

17.
《Scientia Horticulturae》2005,106(2):147-161
Pepper plants grown in recirculating nutrient solution were exposed to NaCl-salinity (60 mM NaCl, 8 dS m−1) imposed either to the entire or to half of the root system and compared to plants supplied with a standard nutrient solution (1.9 dS m−1). The saline solution was obtained by adding NaCl to the standard nutrient solution. In the split-root treatment, the root compartment not exposed to salinity was supplied with raw water (0.38 dS m−1). Both the stem and the root dry weights were markedly restricted by salinity, irrespective of salinizing half or the entire root system. In the split-root treatment, the dry weight of the root compartment receiving raw water did not differ significantly from that exposed to salinity. The net photosynthesis and the leaf chlorophyll content were restricted by both salinity treatments, but the decrease was more marked when the entire root system was exposed to salinity. In contrast, the stomatal conductance and the transpiration rate were equally reduced, regardless of salinizing the entire or part of the root system. The leaf Na and Cl concentrations were raised by the NaCl-salinity, but only in one sampling date the increase was significantly higher when the entire root zone was exposed to salinity, as compared with salinization of half of the root system. Salinity reduced significantly the leaf K, Ca, and Mg uptake but not to levels that could cause nutrient deficiencies. These results indicate that pepper is susceptible to high salinity, predominantly due to reduced stomatal conductance. However, after long-term exposure to salinity the growth may be suppressed due also to inhibition of photosynthesis at chloroplast level. The adverse effects of high NaCl-salinity are hardly mitigated when only a part of the root system is salinized, which indicates that the response is governed by root exposure to high NaCl concentrations and not by inefficiency of the roots to take up water.  相似文献   

18.
Summary

The use of leafy cuttings to propagate ornamental shrubs such as Corylus maxima cv. Purpurea is often hampered by “weaning” problems. These arise when the rooted cuttings are removed from the supportive environment designed to promote rooting and are transferred to a more natural, but relatively stressful, environment. The shrivelling of leaves which ensues points to some failure of normal plant water relations, which may be caused either by excessive water loss from the leaves, or an inadequate water supply from the roots, or a combination of these factors. To understand this problem more fully, the root hydraulic conductance of C. maxima cv. Purpurea cuttings was investigated, and compared with that of Weigela florida cv. Variegata, a shrub which does not exhibit weaning problems. The root hydraulic conductance for both species increased with the size of the root system, and root fresh weight was shown to provide a useful basis for relative measurements of root conductance. On this basis, cuttings of W. florida exhibited a higher root hydraulic conductance than comparable C. maxima cuttings (1.5 × 10?4 and 9.7 × 10?5 g s?1 MPa?1 groot?1 respectively), but the difference was not sufficiently large to account for the differences in weaning of these two species. It is suggested that the adventitious root system of C. maxima is functioning normally, but that it cannot supply enough water to balance uncontrolled water loss from the leaves.  相似文献   

19.
Summary

Two levels of humidity, high, 0.1 kPa vapour pressure deficit (vpd) and control 0.5 kPa vpd, and four nutrient feed K/Ca mM ratios (4/7, 10/7, 4/2 and 10/2) were applied in all factorial combinations to a nine-week old tomato (Lycopersicon esculentum Mill.) crop for 63 d. The effect on gas exchange, water relations, vegetative growth, yield and accumulation of Ca and K in the shoot was examined. High humidity had a deleterious effect on leaf expansion, delayed truss and fruit maturity and reduced fruit yield. Water uptake was reduced and the Ca concentration of leaf and fruit tissue was increased under high humidity compared with plants grown under control humidity; K accumulation was unaffected. The accumulation of K and Ca in the shoot appeared to be poorly related to the rate of transpiration. The high (10/2 mM) K/Ca ratio nutrient feed had little effect on vegetative growth and yield compared with the low (4/7 mM), but restricted Ca uptake to the fruits at both the high and the control humidity. During the measurement period, 0900–1300 hours, stomatal conductance and leaf water status remained high at elevated humidity, compared with a progressive reduction in leaf water status and low stomatal conductance in the control humidity. A/ci gas exchange analysis where A is the net CO2 assimilation rate and ci is the intercellular partial pressure of CO2 suggested that, at high humidity, the photosynthetic capacity of the leaves was reduced because of a lower in vivo carboxylation efficiency. However, the mechanism(s) responsible for reduced leaf expansion remains unclear. The complex interrelations between physiological responses, leaf expansion and the uptake and distribution of K and Ca to the shoot, are discussed.  相似文献   

20.
采用营养液栽培,以黄瓜品种新泰密刺为试材,研究了外源Ca(NO3)2对盐胁迫(NaCl 65 mmol.L-1)下黄瓜幼苗生长、膜质过氧化产物丙二醛(MDA)含量及电解质渗漏率的影响。结果表明:Ca(NO3)2处理可以缓解盐胁迫对黄瓜幼苗生长的抑制,降低盐胁迫引起的MDA含量和电解质渗漏率升高的幅度。其中以2.0mmol.L-1Ca(NO3)2处理效果最好,黄瓜幼苗地上部鲜质量、地上部干质量、株高、茎粗、叶面积、地下部鲜质量、地下部干质量、总根长、总根表面积、总根体积、根尖数等生长指标均显著高于单独盐胁迫处理,同时显著降低了盐胁迫下MDA和电解质渗漏率的上升辐度。  相似文献   

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