Effect of preharvest spraying Cryptococcus laurentii on postharvest decay and quality of strawberry

Application of a suspension (log 8.0/ml) of Cryptococcus laurentii prior to harvest led to a reduction in Botrytis cinerea decay of strawberries stored at 4 or 20 °C, for 12 or 4 days, respectively. The frequency of spraying antagonist significantly influenced disease incidence in strawberry fruit. The best inhibition of disease was achieved when fruit sprayed C. laurentii with three applications that began 6 days prior to harvest, and the incidence of gray mold and natural decay treated with this method was 21% and 11%, compared with 88% and 62% in the control after storage at 20 °C for 4 days. A similar result occurred in the treated fruit after storage at 4 °C for 12 days. Dilation plate counts on Rose Bengal agar and scanning electron microscopy results showed that three applications with C. laurentii at 6, 3 and 0 days before harvest improved its ability to colonize the epidermis of strawberry fruit in the greenhouse and during storage compared to single application. In addition, antagonistic yeast spraying before harvest could reduce the weight loss, delay the decrease of the firmness and ascorbic acid, but had no significant effect on the contents of soluble solids, titratable acidity and fruit surface color. These results suggested that preharvest spraying with C. laurentii might be a promising alternative to fungicide application for decay control of strawberry.     

Non-destructive assessment of flesh firmness and dietary antioxidants of greenhouse-grown tomato (Solanum lycopersicum L.) at different fruit maturity stages

Non-destructive methods have been widely recognized for evaluating fruit quality traits of many horticultural crops and food processing industry. Destructive (analytical) test, and non-destructive evaluation of the quality traits were investigated and compared for ‘Red Rose’ tomato (Solanum lycopersicum L.) fruit grown under protected environment. Fresh tomato fruit at five distinctive maturity stages namely; breaker (BK), turning (TG), pink (PK), light-red (LR), and red (RD) were labeled and scanned using the handheld near infra-red (NIR) enhanced spectrometer at a wavelength range of 285–1200 nm. The labeled tomato samples were then measured analytically for flesh firmness, lycopene, β-carotene, total phenolic content (TPC) and total flavonoids content (TFC). The results revealed that quality traits could be estimated using NIR spectroscopy with a relatively high coefficient of determination (R²): 0.834 for total phenolic content, 0.864 for lycopene, 0.790 for total flavonoid content, 0.708 for β-carotene; and 0.679 for flesh firmness. The accumulation of Lyco and β-Car rapidly increased in tomatoes harvested between the TG and the LR maturity stages. Harvesting tomatoes at BK maturity stage resulted in significantly higher flesh firmness than harvesting at the later maturity stages. Tomato fruits had the lowest TPC and TFC contents at the earliest maturity stage (BK), while they had intermediate TPC and TFC levels at LR and RD maturity stages. NIR spectroscopic measurements of fruit firmness and lipophilic antioxidants in tomato fruit at various maturity stages were partially in accordance with those estimated by destructive (analytical) methods. Based on these findings, we recommend using non-destructive NIR spectroscopy as an effective tool for predicting tomato fruit quality during harvest stage and postharvest processing.     

Regulation of Harvest-induced Senescence in Broccoli (Brassica oleracea var. italica) by Cytokinin, Ethylene, and Sucrose

Broccoli (Brassica oleracea var. italica) deteriorates rapidly following harvest. The two plant hormones ethylene and cytokinin are known to act antagonistically on harvest-induced senescence in broccoli: ethylene by accelerating the process, and cytokinin by delaying it. To determine the level at which these hormones influenced senescence, we isolated and monitored the expression of genes normally associated with senescence in broccoli florets treated with exogenous 6-benzyl aminopurine (6-BAP), 1-aminocyclopropane-1-carboxylic acid (ACC), a combination of 6-BAP and ACC, and sucrose, in the five days following harvest. Exogenous 6-BAP caused both a reduction (BoACO) and an increase (BoACS) in ethylene biosynthetic gene expression. The expression of genes used as senescence markers, BoCP5 and BoMT1, was reduced, whereas BoCAB1 levels were maintained after harvest in response to exogenous 6-BAP. In addition, the expression of genes encoding sucrose transporters (BoSUC1 and BoSUC2) and carbohydrate metabolizing enzymes (BoINV1 and BoHK1) was also reduced upon 6-BAP feeding. Interestingly, the addition of ACC prevented the 6-BAP-induced increase in expression of BoACS, but 6-BAP negated the ACC-induced increase in expression of BoACO. The culmination of these results indicates a significant role for cytokinin in the delay of senescence. The implication that cytokinin regulates postharvest senescence in broccoli by inhibiting ethylene perception and/or biosynthesis, thus regulating carbohydrate transport and metabolism, as well as senescence-associated gene expression, is discussed and a model presented.     

高氧对果蔬采后生理影响研究进展

高氧（21%-100%O2）贮藏是近几年发展起来的果蔬采后处理技术之一.概述了高氧对果蔬采后生理如呼吸作用、乙烯合成、组织褐变、活性氧代谢及抗氧化能力、风味等方面的影响,还介绍了高氧对病原微生物生长和采后果蔬腐烂控制的作用.     

水杨酸处理对采后园艺产品的作用

本文结合作者自己的研究结果 ,综述了水杨酸对园艺产品的采后作用 (包括延长切花保鲜期、减轻果实腐烂、推迟洋葱等产品的发芽和对果蔬产品贮藏期间品质、呼吸速率、乙烯释放、抗逆、活性氧代谢方面影响 )的研究进展 ,并对这些结果进行了分析 ;对高浓度外源SA处理引起的负面作用以及存在的一些问题进行了探讨     

Chrysanthemum: advances in tissue culture, cryopreservation, postharvest technology, genetics and transgenic biotechnology

Members of the Chrysanthemum-complex include important floricultural (cut-flower) and ornamental (pot and garden) crops, as well as plants of culinary, medicinal and (ethno)pharmacological interest. The last 35 years have seen a tremendous emphasis on their in vitro tissue culture and micropropagation, while the latter 10–15 years has seen a surge in transformation experiments, all aimed at ameliorating aesthetic and growth characteristics of the plants. This review highlights all available literature that exists on ornamental Chrysanthemum in vitro cell, tissue and organ culture, micropropagation and transformation.     

紫花和桂香芒果采后色泽转化的研究

紫花和桂香芒果品种随着果实后熟的进程,叶绿素含量逐渐下降,类胡萝卜素含量逐渐增加。与桂香相比,紫花芒果含有较低的叶绿素和较高的H2O2,与其果实转黄相一致。乙烯利和H2O2处理明显促进了紫花芒果的叶绿素分解和色泽转化,而对桂香芒果的叶绿素分解虽有一定的促进作用,但对外观色泽转化的影响不明显。     

杨桃果实采后生理研究(综述)

概述了国内外对杨桃果实采后主要营养成分的分析、呼吸、乙烯释放、主要生理病害,并介绍了不同贮藏条件或处理对杨桃果实采后贮藏性影响的研究概况。     

控制果蔬采后病害的生物学技术

化学农药对环境和农产品的污染直接影响人类的健康,已成为当今公众所关注的主要问题之一。为了保证农产品的卫生和安全,世界各国都在探索能代替化学农药的防病新技术。生物防治是近年来被证明很有成效的新途径,它主要是利用微生物之间的拮抗作用,选择对农产品不造成危害的微生物来抑制引起采后腐烂的病原真菌的生长。生物防治的研究主要包括主要包括以下三方面：（１）选用有拮抗作用的微生物;（２）利用植物和动物产生的自然抗     

Effect of mycorrhizal colonization and phosphorus on ethylene production by snapdragon (Antirrhinum majus L.) flowers

 We determined the effects of phosphorus (P) concentration and mycorrhizal colonization on ethylene production by flowers of snapdragons (Antirrhinum majus L.). Mycorrhizal colonization in a soil-less medium did not significantly affect the total number of flowers per spike or flower P concentration, but it significantly increased flower vase-life and significantly decreased flower ethylene production. This demonstrates for the first time that mycorrhizal colonization can have a non-localized effect on host ethylene production. The reduction in ethylene production caused by mycorrhizal colonization was as large as the variation in ethylene production among snapdragon cultivars. Thus, mycorrhizal colonization may be a viable alternative to toxic ethylene inhibitors such as silver thiosulfate. Increased fertilizer P concentration (15 versus 3 μg P ml^–1) significantly increased plant fresh weight and the total number of flowers per spike. In contrast to mycorrhizal colonization, increased fertilizer P concentration resulted in an increase in ethylene production. There was no significant effect of fertilizer P concentration on vase-life. This suggests that factors other than ethylene have at least partial control over vase-life. Postharvest amendment of individual flowers with phosphate also significantly increased flower ethylene production. Phosphorus apparently does not mediate the mycorrhizal effect because mycorrhizal colonization decreased ethylene production without significantly influencing flower P concentration. Moreover, treatment with phosphate increased flower ethylene production. Mycorrhizal colonization did not significantly influence response to exogenous ethylene. Accepted: 14 June 1999