Postharvest Attributes of “Washington Navel” Orange as Affected by Preharvest Foliar Application of Calcium Chloride,Potassium Chloride,and Salicylic Acid

ABSTRACT

To evaluate the effects of preharvest foliar application of calcium chloride (CaCl₂), potassium chloride (KCl), and salicylic acid (SA) on postharvest quantitative and qualitative attributes and storage life of “Washington navel” orange, an experiment was conducted during two consecutive years. Solutions including CaCl₂ (1.5% and 3%), KCl (1.5% and 3%), SA (0.015%, 0.03% and 0.045%), and the combination of CaCl₂, KCl, and SA were sprayed on the canopy at the end of the first stage of fruit growth one month after full bloom (fruit diameter was 20 mm) and repeated in late September. The fruits were harvested at commercial maturity stage and were stored at 5°C with 85 ± 5% relative humidity (RH) for 90 days. Quantitative and qualitative characteristics were assessed every month. Preharvest KCl treatment had no significant effect on measured parameters. However, CaCl₂ and SA treatments had the most impact on the quantitative and qualitative characteristics, such as firmness and phenolic content of fruit during storage. The SA treatment enhanced fruit appearance and nutritional value compared to the control but could not prevent the weight loss during storage. The results showed that preharvest spray of CaCl₂, KCl, SA, and their combination had positive effects on storability of “Washington navel” orange fruit during storage. However, the effect of Ca and SA was more. Application of Ca, K, and SA could be beneficial for orange postharvest instead of mixed elements fertilizers.     

Effect of pre- and postharvest salicylic acid treatment on physio-chemical attributes in relation to the vase life of cut rose flowers

With the aim of extending the vase life of cut rose flowers, we investigated whether the application of salicylic acid (SA), pre- and postharvest, could improve this. For this purpose, two individual trials were conducted, using a completely randomised design, with three replications. In the first trial, aqueous solutions of 0, 0.5, 1.0 and 1.5 mM SA were sprayed on roses grown in a controlled greenhouse once the flower buds had appeared, and the second stage was performed two weeks before harvest. The preharvest SA application at 1.5 mM concentration prolonged the vase life of cut roses by improving membrane stability, and decreasing the lipid peroxidation properties. In the second trial, continuous exposure to (0, 0.5, 1.0 and 1.5 mM), and pulses of (0, 5, 10 and 15 mM), SA significantly extended the vase life. Flowers treated with 1.5 (continuous exposure) and 15 mM (pulse) SA showed a significant decrease in weight loss, and antioxidant activity increased, compared to the control solution, but the flowers in the control solution indicated an increase in weight loss. The results show that pre- and postharvest SA application prolonged the vase life of cut roses through improving CAT and POD activity, and decreasing lipid peroxidation.     

‘黄冠’梨采后热处理和钙处理对其钙形态及细胞壁物质代谢的影响

 以‘黄冠’梨为材料,研究了采后热处理（38 ℃热空气24 h）,钙处理（6% CaCl₂浸果15 min）及热加钙处理（6% CaCl₂ + 38 ℃）对果实低温贮藏过程中钙形态及细胞壁物质代谢的影响,以清水浸果为对照。结果表明：果胶钙为果实中主要的钙形态,其含量占全钙的49.7% ~ 55.8%,钙处理、热加钙处理果实的总钙含量与对照相比分别增加了22.95和31.58 µg · g^-1;钙处理、热加钙处理显著抑制了果实纤维素、原果胶、水溶性钙及果胶钙含量的下降,促进了草酸钙含量的增加,延缓了果实硬度的下降;热处理、热加钙处理显著降低了多聚半乳糖醛酸酶（PG）、果胶甲酯酶（PME）和纤维素酶活性。相关分析表明,果实硬度与纤维素、原果胶、水溶性钙和果胶钙含量呈极显著正相关,与可溶性果胶含量呈极显著负相关;PG和纤维素酶与果实硬度均呈极显著负相关,PME与果实硬度的相关性不显著。钙处理、热加钙处理通过抑制可溶性钙向难溶性钙转化、细胞壁组成成分降解以及降低细胞壁降解酶活性,延缓果实软化,其中以6% CaCl₂ + 38 ℃的处理效果最好。     

Storage temperature affects the quality of cut flowers from the Asteraceae

The respiration of cut flowers of gerbera (Gerbera jamesonii H. Bolus ex Hook.f. 'Vesuvio') and sunflower (Helianthus annuus L.) increased exponentially with increasing storage temperature. Poststorage vase life and negatively gravitropic bending of the neck of the flowers were both strongly affected by simulated transport at higher temperatures. Vase life and stem bending after dry storage showed highly significant linear relationships (negative and positive, respectively) with the rate of respiration during storage. The data indicate the importance of maintaining temperatures close to the freezing point during commercial handling and transport of these important commercial cut-flower crops for maximum vase life.     

Improving yield,quality, and shelf life of Thompson seedless grapevine by preharvest foliar applications

Ten-year-old Thompson seedless grape vines were sprayed during 2009 and 2010 growing seasons with putrescine (Put), gibberellic acid (GA₃), ascorbic acid (AA), ethephon (Eth), salicylic acid (SA), cytofex (CPPU) and calcium chloride (CaCl₂) at two stages of berry development; pea stage (4–5 mm fruitlet diameter, ∼30–35 days after fruit set) and veraison stage (when approximately 20% of the berries on 50% of the clusters had softened) in order to investigate their influence on yield and postharvest fruit quality characters at commercial harvest day as well as the berry keeping quality. Cluster and berry quality characters as well as vine yield were improved by all sprayed chemicals, especially Put, GA₃, SA, CPPU and CaCl₂. GA₃ increased cluster and berry width, and resulted in better clusters shape. A positive increase in berry firmness was obtained by Put, GA₃, CPPU, SA and CaCl₂ sprays. Berry adherence strength increased and the percentage of unmarketable berries decreased by all sprayed compounds except Eth. Shelf life (keeping quality) was increased by spraying Put, GA₃, SA, CPPU and CaCl₂, as they increased berries firmness and decreased the percentage of unmarketable berries after keeping at ambient temperature for seven days after harvest.     

非洲菊鲜切花弯颈部位及有关原因

 研究了非洲菊鲜切花瓶插过程中弯颈易发部位(中部茎段) 及其上部、下部茎段水分平衡动态和某些生理指标的变化。结果表明, 非洲菊鲜切花瓶插过程中: ①鲜样质量和含水量先增后减, 吸水逐渐减少, 蒸腾失水相对稳定, 水分饱和亏缺增大; ②可溶性蛋白质含量呈下降趋势, 但上部茎段一直高于中部和下部茎段; ③MDA 的含量呈上升趋势, 上部茎段低于中部和下部茎段; ④中部茎段的粗纤维含量与上部茎段无显著差异, 但大大低于下部茎段; ⑤瓶插初期POD 活性略有下降, 后期迅速上升, 上部茎段POD 活性一直高于中部茎段和下部茎段。讨论了中部茎段易发生弯曲的原因。     

Citric acid,sucrose and Cu2+ as potential vase treatments for cut Acacia holosericea G. Don foliage stems

The short vase life of Acacia holosericea cut stems needs to be improved before they are marketable as cut foliage for floral arrangement. The effects of citric acid, Cu²⁺ and sucrose were investigated for their efficacy in postharvest treatments to extend vase life of the cut stems. Five experiments were conducted involved combinations of citric acid either with Cu²⁺ or sucrose. Vase life, relative fresh weight (RFW), and vase solution uptake were measured as indicators of cut stem quality. The effect of Cu²⁺ alone was shown to be consistently superior in improving vase life by up to 1.9-fold as compared with deionised water control. Citric acid had a smaller effect than Cu²⁺ and did not act synergistically with Cu²⁺. Sucrose on its own or in combination with citric acid did not improve vase life significantly; instead sucrose promoted early wilting or desiccation of the cut foliage.     

Improving the postharvest performance of cut spray ‘Prince’ carnations by vase treatments with nano-silver and sucrose

The postharvest performance of cut spray-type carnations (Dianthus caryophyllus L.) is often limited by the opening, longevity, and coloration of individual florets, and is apparently related to water stress and sugar deficiency. In this study, we found that, compared with deionised water-treated controls, the vase life of cut spray ‘Prince’ carnations was extended by 2.1–4.6 days when held in vase solutions containing1–5 mg L^–1 nano-silver (NS). Moreover, combination treatments with 5 mg L^–1 NS and 2%, 3%, or 4% sucrose consistently further prolonged the vase life, prominently promoted floret opening, and increased the bright pink coloration of petals, thereby markedly enhancing quality performance. Overall, the 5 mg L^–1 NS plus 3% sucrose treatment provided the longest vase life extension (6.6 days) compared with the control, and significantly increased the anthocyanin content in floret petals. Besides, we also showed that the treatment with 5 mg L^–1 NS alone or 5 mg L^–1 NS plus 3% sucrose significantly enhanced their vase solution uptake and relative fresh weight. Further, scanning electron microscopy observations revealed that the NS vase treatments evidently alleviated vascular occlusion by inhibiting bacterial colonisation and biofilm formation on their stem-end cut surfaces and in the xylem vessels.     

杧果采前喷施茉莉酸甲酯对其抗病性和采后品质的影响

 以‘台农1号’杧果（Mangifera indica L.‘Tainong 1’）为试材,研究了采前喷施茉莉酸甲酯（MeJA）处理对杧果抗病性和采后品质的影响及其相关机理。结果表明,与对照果实相比,50 μmol · L^-1 MeJA采前处理显著降低了采收时的病果率和贮藏期的病情指数,抑制了接种炭疽病菌果实的病斑直径;有利于杧果贮藏品质的保持,提高了果肉中维生素C含量,延缓了可溶性糖含量的升高和可滴定酸含量的降低;同时,采前MeJA处理可以提高杧果果皮中苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）、多酚氧化酶（PPO）和β–1,3–葡聚糖酶（GLU）等防御酶的活性,提高贮藏早期的过氧化氢（H₂O₂）水平,抑制贮藏后期H₂O₂和MDA含量的积累。这些结果表明,采前MeJA处理提高杧果抗病性和保持果实品质与激活杧果的防御系统及降低膜脂过氧化程度有关。     

Copper distribution and ionic form effects for postharvest treatments of cut Acacia holosericea stems

A short postharvest life is the major constraint associated with cut Acacia flowers and foliage. Treatment with CuSO₄ (Cu²⁺) has previously been shown to improve the longevity of cut Acacia holosericea stems. Towards refining the treatments, a range of Cu²⁺ and Cu⁺ salts were assessed for relative efficacy in improving vase life and water relations of A. holosericea. Five hour pulses with the Cu²⁺ salts CuSO₄, CuCl₂, (CH₃COO)₂Cu and Cu(NO₃)₂ at 2.2 mM gave equally longer vase lives by ∼2.5-fold over deionised water (DIW) and standard tap water (STW) controls. The same Cu²⁺ salts at 0.5 mM in the vase solution also gave significantly (P < 0.05) improved vase life, relative fresh weight and water uptake compared to the DIW control. For Cu²⁺ versus Cu⁺, optimum concentrations with Cu²⁺ could not be directly compared due to the low solubility of the Cu⁺ salt CuCl. However, Cu⁺ from CuCl at 0.415 mM also had positive effects on vase life compared to the DIW control. Thus, both Cu²⁺ and Cu⁺ treatments can enhance vase life parameters for cut A. holosericea foliage. The benefits were irrespective of the counter ion and, thus, Cu²⁺ and Cu⁺per se were responsible. The most effective Cu²⁺ pulse treatment decreased stomatal conductance of phyllodes initially, but did not cause sustained stomatal closure. Cu accumulated to greater levels in basal stem and phyllode tissues than in upper stem and phyllode tissues of cut A. holosericea stems. Possible mechanisms of Cu²⁺/Cu⁺ action are discussed.     

Water loss and postharvest characteristics of cut roses grown at high or moderate relative air humidity

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.     

Improving the performance of calcium-containing spray formulations to limit the incidence of bitter pit in apple (Malus x domestica Borkh.)

Laboratory and field experiments were carried out with apples (Malus x domestica Borkh.) cv. ‘Golden Reinders’, to assess the efficacy of sodium salt of carboxymethyl ether of cellulose (0.5%, CMC) as an adjuvant for Ca spray formulations containing either Ca-chloride or Ca-propionate as active ingredient (120 or 250 mM Ca). This additive significantly increased the retention of Ca-containing solutions by the apple skin and prolonged the process of drying of the solution at room temperature. Four days after immersion of apples in 0.5% CMC plus CaCl₂ or Ca-propionate solutions (120 and 250 mM Ca) significant Ca increases were recorded in the peel and cortex of treated fruits. Application to apple trees of in-season sprays containing 250 mM CaCl₂ plus 0.05% Tween 20, Ca-propionate (120 and 250 mM Ca) plus 0.5% CMC or 250 mM CaCl₂ plus 0.5% CMC had no impact on fruit yield and quality, but significantly limited the rate of bitter pit incidence during the following 3-month cold-storage period. Evidence is provided that addition of appropriate adjuvants to Ca sprays can favour the distribution of Ca into the apple fruit and helps to reduce the incidence of Ca-related disorders over the postharvest cold-storage period.     

Addition of salicylic acid to nutrient solution combined with postharvest treatments (hot water,salicylic acid,and calcium dipping) improved postharvest fruit quality of strawberry

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.     

Effect of postharvest application of calcium on ripening rates of pears and bananas

Dipping unripe pears (cv Williams Bon Chretien) in a solution of calcium chloride under reduced pressure (125-375 mm Hg) and subsequent storage at 20°C delayed ripening by up to 40% of the time taken for control fruit to ripen. The Ca-treated fruit ripened normally and a taste panel found that it was of good eating quality. However, dipping unripe bananas (cv Cavendish) in CaCl₂ solution, whether under ambient or reduced pressure, accelerated ripening.     

Factors affecting the vase life of fronds of maidenhair fern

Cut fronds of maidenhair fern (Adiantum raddianum), which last only 3 days in DI water, were used as a model system to study factors affecting the vase life of cut greens. Solutions containing 25 mg 1^?1 Ag⁺ increased vase life 5-fold. Other biocides (8-hydroxyquinoline citrate, a quaternary ammonium compound, or 8-hydroxyquinoline citrate + NaOCl) had little effect on vase life, while inhibitors of ethylene (C₂H₄) production (Co²⁺, aminooxyacetic acid) increased vase life. Wound C₂H₄ production by the cut ends of the stipes declined during the first 2 h after cutting. The hypothesis that this C₂H₄ is the cause of the brief vase life of maidenhair fern is discussed.     

保鲜液对蒟蒻薯切花瓶插寿命的影响

 蒟蒻薯（Tacca chantrieri Andre）是观赏价值较高的稀有黑色切花,但瓶插寿命较短,对其进行保鲜研究具有重要意义。用蔗糖、8–羟基奎宁（8-HQ）和柠檬酸按三因素二水平的正交设计配制瓶插保鲜液,通过观察切花形态变化,测定瓶插寿命和鲜样质量,研究瓶插液的保鲜效果。结果表明,与对照相比,各处理均能不同程度地延缓切花衰老,其中A处理,即2%蔗糖 + 100 mg · L^-1 8-HQ + 200 mg · L^-1柠檬酸 + 50 mg · L^-1 6-BA + 100 mg · L^-1 K₂HPO₄处理效果最好,花枝寿命和花须寿命分别比对照长17 d和14 d,是蒟蒻薯切花较好的瓶插保鲜配方。     

乙烯对‘洛阳红’牡丹切花开放衰老进程及内源乙烯生物合成的影响

 以开花指数为1级的‘洛阳红’牡丹切花为试材,研究了外源乙烯和乙烯作用抑制剂1-甲基环丙烯（1-MCP）处理对其采后开花衰老进程中开花指数、花径增大率、瓶插寿命、内源乙烯生成量及乙烯生物合成关键酶ACC合成酶（ACS）和ACC氧化酶（ACO）活性的影响,从乙烯生物合成角度探讨了乙烯对其采后开花衰老的调节机理。结果表明,10 μL·L^-1乙烯处理6 h明显加快了‘洛阳红’花朵开放进程,缩短了切花的瓶插寿命,并促使其在盛开后出现严重落瓣;1.0 μL·L^-1 1-MCP处理6 h则延缓了花朵开放,延长了瓶插寿命,但却影响了部分切花的充分开放;内源乙烯的生成分别受乙烯和1-MCP处理的促进和抑制,与切花的开放衰老进程密切相关。不同处理后ACS、ACO酶活性分析表明,ACS活性变化与内源乙烯的生成相联系,是影响牡丹切花开放衰老进程的主要因子,这与目前得出的ACS是植物乙烯生物合成限速酶的研究结果相一致。     

The effect of preservatives on water balance in cut clematis flowers

A positive water balance is crucial for longevity of cut shoots. When water loss by transpiration exceeds water uptake by cut flowers, wilting symptoms appear. Clematis is a very attractive plant which can be used as a cut flower provided that suitable cultivars are chosen. The vase life of four cultivars tested ranged between 6.7 days and 9.0 days and the standard preservative – 200 mg·dm^?3 8-hydroxyquinoline citrate (8HQC) plus 2% sucrose – prolonged it significantly in two cultivars, while 8HQC alone was efficient in only one. The preservatives delayed reduction in fresh weight. An enhancement of water uptake by the preservatives resulted in prolonged vase life of flowers in two cultivars. However, the effect of preservatives on transpiration was not related to longevity. In addition, longevity did not depend on the xylem vessel size: the cultivar with the longest vase life had the lowest average xylem vessel diameter while the cultivar with the largest vessels had an intermediate vase life. Preservatives did not always affect the number of blockages in xylem appearing during vase life. Generally, the effects of preservatives on the elements of water balance in cut shoots of clematis were not directly related to the postharvest longevity.     

Evaluation and improvement of post-harvest performance of cut Viburnum tinus inflorescence

Post-harvest performance of cut viburnum inflorescences was examined in the present study. Harvesting viburnum at three developmental stages resulted in significant differences on flower opening rate (FOR) and flower abscission rate (FAR), but not on vase life. Harvesting at Stage III (>50% open flowers) resulted in highest flower opening percentage, whereas harvesting at Stage I (10–30% open flowers) in significantly lower flower abscission percentage. Pulsing with 20 or 40 mg/l AgNO₃ for 24 h extended vase life by 1.6 and 1.9 days, respectively, compared to the controls. Furthermore, flower abscission was significantly reduced after 20 or 40 mg/l AgNO₃ treatments by 51 and 62%, respectively, compared to the controls. In contrast, vase solutions containing 100 mg/l DICA or 100 and 200 mg/l methanol did not extend vase life of cut viburnum inflorescences, but significantly reduced flower abscission. Vase solutions containing 1 or 2% (w/v) sucrose negatively affected vase life, flower opening and flower abscission of viburnum inflorescence. Post-harvest treatments with 1-MCP at 10 μl/l in an ethylene-free environment resulted in extension of vase life and in significant reduction of FAR and respiration rates compared to the controls. Vase life of 1-MCP treated inflorescences was increased by 4.2 days compared to the controls. FAR of 1-MCP treated inflorescences remained significantly lower from the second to the eighth day of the vase life period.     

Response of gladiolus (Gladiolus spp) plants after exposure corms to chitosan and hot water treatments

The state of Morelos, Mexico has gradually become an important producer of gladiolus. Some preconditioning treatments of corms are empirically done causing uneven emergence and low quality of flowers. In this investigation, before planting, gladiolus corms var. ‘Blanca Borrego’ were dipped in chitosan (chitosan reagent and commercial chitosan Biorend^®), in hot water at various temperatures and in treatments combined with Biorend^® at 1.5% and hot water. Results indicated that the most influenced variables were corm germination, number of flowers per spike, number of cormlets and vase life. Overall, the commercial product Biorend^® at 1.5% accelerated corm emergence in approximately 4 days, the number of flowers increased by 2–7 and the vase life extended for 3 days. The number of cormlets was also duplicated. Corms dipped in the commercial chitosan Biorend^® at 1.5% at different intervals of time were not greatly affected except for the emergence and number of cormlets. However, for this experiment there were significant effects on the number of leaves and flowers because of the interactions between chitosan and the immersion time. The temperature of 55 °C affected plant development because emergence was delayed by 6 days; and there were less number of leaves, flowers and cormlets. On the other hand, the incidence of Fusarium oxysporum in naturally infected corms was 0% at temperatures of 55 °C and 50 °C. Immersion times (0, 10, 15 and 20 min) in hot water at 50 °C did not show significant effects on plant development and vase life. Corms dipped in Biorend^® at 1.5% and hot water at 50 °C accelerated their emergence for about 1–7 days, the number of flowers increased by two, extended the storage life for 1–3 days and increased the number of cormlets. The integration of these two treatments -Biorend^® and hot water- might be a good option for increasing the gladiolus plant quality and vase life.