The viability of Penicillium expansum Link conidia in sporulating culture declined rapidly when exposed to 38 °C, and when conidia were exposed to 38 °C prior to inoculation of apple fruits (Malus ×domestica Borkh.), the resulting lesions were smaller than those on fruit inoculated with nonheated conidia. `Gala' apples were heated after harvest (38 °C for 4 days), pressure infiltrated with a 2% solution of CaCl2, or treated with the antagonist Pseudomonas syringae van Hall, alone or in combinations to reduce postharvest decay caused by Penicillium expansum. After up to 6 months in storage at 1 °C, no decay lesions developed on fruit that were heated after inoculation with P. expansum, or any combination of P. expansum, antagonist, or Ca. Parallel lots of heat-treated and nonheated fruit that were either infiltrated or not infiltrated with Ca were stored up to 6 months. They were then inoculated with P. expansum alone, or with the antagonist followed by P. expansum. Prior heat treatment did not influence lesion size. Calcium alone, the antagonist alone, and heat plus Ca all reduced the incidence of decay by ≈25%, whereas heat plus the antagonist reduced it by 70%. Calcium plus the antagonist or Ca plus the antagonist and heat reduced decay incidence by 89% and 91%, respectively. The integrated strategy of heat-treating fruit, followed by Ca infiltration and then treatment with an antagonist, may be a useful alternative to controlling postharvest decay with fungicides.
The marketable period of fresh-cut `Tommy Atkins' and `Kent' mango cubes was 3 to 5 days at 10 °C and 5 to 8 days at 5 °C. The marketable period was extended by 1 to 2 days when cubes were held in a 4 kPa O2 + 10 kPa CO2 or 2 kPa O2 + 10 kPa CO2 (balance N2) atmospheres, depending on cultivar and temperature. Variations in texture (shear force), pH, and soluble solids were greater among cubes from different mango lots than among cubes held at different temperatures or atmospheres. Yeast count increased more with time than did the total mesophilic aerobic count, and the increase was less under controlled atmosphere (CA) than in air at 10 °C. The CA was beneficial in maintaining quality of the cubes; however, low temperature was more effective than CA.
Placing a daffodil (Narcissus pseudonarcissus L. `Carlton') flower in a vase with a rose (Rosa hybrida L. Sonia) flower reduced water uptake by the rose and resulted in precocious wilting of its leaves and flower and in pedicel bending. These symptoms were also observed when mucilage from daffodil stems was placed in the vase water. The effects of the mucilage and the daffodil stem were overcome by adding 8-hydroxyquinoline (HQC) to the vase solution. HQC inhibits ethylene production and is an antimicrobial compound. Aminoethyoxyvinylglycine (AVG) or silver thiosulfate (STS), inhibitors of ethylene synthesis and action, respectively, did not alleviate the mucilage effects, but sodium hypochlorite, an antimicrobial compound, did. Bacterial counts in the basal 5-cm segment of rose stems increased after placing mucilage or a daffodil stem in the vase water, and counts were reduced by adding HQC or sodium hypochlorite. One daffodil stem also reduced the vase life of tulips (Tulipa gesneriana L. `Frappant' and `Apeldoorn'), which showed precocious leaf yellowing. This was not alleviated by HQC and was also found when mucilage was placed on the leaf surface. Placing mucilage on the leaf produced no effect in roses. Separating the mucilage indicated that the effect in roses is mainly due to the sugar and polysaccharide fraction and the effect in tulips is due to a fraction containing several alkaloids. The results indicate that the decreased vase life of rose flowers, after one daffodil is placed in their vase water, is due to daffodil mucilage, which, in the rose cultivar tested, blocks water uptake, mainly as a result of increased bacterial growth. In the tulip cultivars tested, the negative effect on vase life is primarily due to mucilage toxicity.
Out of the 25 microorganisms commonly occuring in carnation (Dianthus caryophyllus L. ‘Improved White Sim’) vase solutions, 3 greatly reduced carnation vase life when added individually to vase solutions. Some of these microorganisms also reduced the vase life of roses (Rose hybrida ‘Cara Mia’), chrysanthemums (Chrysanthemum × morifloium Ramat. ‘May Shoesmith’) and other cultivars of carnation (‘Improved Red Sim’ and ‘Improved Pink Sim’). The microorganisms that reduced flower vase life were tentatively identified as a yeast, a fluorescent pseudomonad and a nonfluorescent pseudomonad. A 10-fold reduction in the initial inoculum level affected neither the final microbial concentrations nor the vase life of the test flowers. The effects of the different microbes were not correlated with their effects on solution pH.
: Liviidae)], which facilitates disease spread ( Capoor et al., 1974 ). The bacteria have an uneven distribution in the canopy of the trees ( Tatineni et al., 2008 ); however, they are evenly distributed in feeder roots, with a preference for horizontal
nitrifying bacteria for ammonium. Also, there is no scientifically established reconciling pH for these operating systems, which contain plants, fish, and nitrifiers—each with their own optimum environmental requirements. Recommended pH for tilapia is 6.0 to
monitors biological variables such as counts of aerobic bacteria and fungi to indicate contamination or ineffective treatment [ American Public Health Association (APHA), 1995 ; Maier et al., 2009 ]. The reduction of bacterial counts from water samples
and tested on sweet pepper only. Table 1. Bacterial endophytes used to evaluate bacteria-emitted volatile compounds on plant growth promotion. Table 2. Evaluation of bacteria endophytes for volatile compounds that promote plant growth in
ability (e.g., pathogenic bacteria, fungi, and nematodes), and the number of beneficial microbes decreases, thus affecting the normal growth of crops and causing yield reductions. The use of reasonable cropping systems and the employment of allelopathy
-harvesting areas. Pate and Nummer (2013) found that specialty crop production workers had high number of bacteria present on their hands and at multiple farms workers tested positive for Salmonella , Staphylococcus aureus , coliforms and generic E. coli . Our