Increasing maturity reduces wound response and lignification processes against Penicillium expansum (pathogen) and Penicillium digitatum (non-host pathogen) infection in apples

Penicillium expansum is the main postharvest pathogen of pome fruit and is a necrotrophic fungus that requires wounds to infect the fruit. Therefore, injuries caused during harvest and postharvest handling provide an optimal locus for infection. In this study, the effect of wound response in apples harvested at three different maturity stages and stored at two different temperatures (20 and 0 °C) infected with P. expansum (pathogen) and Penicillium digitatum (non-host pathogen) was evaluated. The effect of wounding and pathogen inoculation on lignin content was also quantified. At 20 °C, less decay incidence and severity were observed when time between wounding and inoculation increased, and these differences were more important in fruit from immature and commercial harvests. However, at 0 °C, wound response was too slow to prevent P. expansum infection. Lignin content was highest in fruit from the immature harvest. Our results indicated that maturity and storage temperature play an important role in apple wound response. This is the first report demonstrating that P. digitatum, a non-host pathogen, was able to develop rots in over-mature apples.     

采用优化特征子集选取和改进SVR的养殖禽舍温度预测算法

为提高养殖禽舍温度预测算精度，降低数据冗余度和差异性对预测结果的影响，提出一种基于智能优化特征子集选取和模糊聚类改进SVR（Support Vector Regression）的温度预测模型。首先，构建最优特征子集选取模型，通过设计最优特征子集选取指标，以降低特征之间冗余度和数据维度；采用改进的离散灰狼算法对特征子集选取模型进行求解，以实现最优特征子集选取。其次，建立模糊聚类改进SVR预测机制，通过设计多度量核FCM（Fuzzy C-means）算法，以实现数据样本自动分类；提出与数据样本分类相对应的SVR预测算法，并采用灰狼算法对SVR参数进行优化，最大程度降低样本数据差异性对预测精度的影响。最后，融合最优特征子集选取和模糊聚类改进SVR预测机制，以实现养殖禽舍温度高精度预测。仿真结果表明，该算法实现不同季节条件下养殖禽舍温度的高精度预测，相比于其他预测算法，预测精度提高约23.7%~37.8%。所提养殖禽舍温度预测算法具有良好的预测性能，具有一定的推广应用价值。     

阿拉尔垦区灰枣及酸枣树根系分布特征差异研究

为了明确酸枣树嫁接灰枣后其根系生长与未嫁接的酸枣树根系分布差异，采用壕沟剖面网格取样法，按照不同根径（＜0.5mm、0.5-2.0mm、2.1-5mm、5.1-10mm、＞10 mm）统计并分析了垂直方向0-80cm、水平方向0-100 cm范围内的根系，探索其根系分布深度、广度以及集中分布区。结果表明:地下40-80cm深度为灰枣根系集中分布区，水平方向集中分布区为20-70cm；地下40-80cm深度为酸枣根系集中分布区，水平方向集中分布区为0-40cm。土壤中也表现出明显的层次结构，灰枣根系分布极不稳定层为地下0-20cm， 60cm以下土层仅存少量根系；酸枣根系密集分布于0-60cm。枣根系距树干越远而越稀疏，随着土层深度的增加呈现“先增加后减小”的趋势。     

Effect of antifungal hydroxypropyl methylcellulose-beeswax edible coatings on gray mold development and quality attributes of cold-stored cherry tomato fruit

Edible composite coatings based on hydroxypropyl methylcellulose (HPMC), beeswax (BW), and food preservatives with antifungal properties, were evaluated on cherry tomatoes during cold storage. Food preservatives selected from previous research work included sodium propionate (SP), potassium carbonate (PC), ammonium phosphate (APh) and ammonium carbonate (AC). Cherry tomatoes artificially inoculated with Botrytis cinerea were coated and stored up to 15 d at 5 °C followed by 7 d of shelf-life at 20 °C. All antifungal HPMC-BW coatings significantly reduced gray mold development on inoculated and cold-stored cherry tomatoes, the SP-based coating being the most effective. Analytical and sensory fruit quality was also evaluated after cold storage and shelf-life. The AC-based coating was the most effective to control weight loss and maintain the firmness of coated cherry tomatoes. Respiration rate, firmness, color, sensory flavor, off-flavor, and fruit appearance were not adversely affected by the application of the antifungal coatings. Overall, the application of HPMC-BW edible composite coatings containing AC could be a promising treatment to extend the postharvest life of cherry tomatoes. Further studies should focus on the modification of some physical characteristics of the coatings in order to enhance the general performance and provide higher peel gloss.     

Applications of salt solutions before and after harvest affect the quality and incidence of postharvest gray mold of ‘Italia’ table grapes

The efficacy of some potassium and calcium based salts, namely potassium sulphate (PS), potassium sorbate (PSo), potassium carbonate (PC), potassium bicarbonate (PB), calcium sulphate (CS), calcium chelate (CCh), calcium chloride (CC) and calcium silicate (CSi) against gray mold of ‘Italia’ table grapes, was evaluated. In in vitro experiments, PSo, PC, PB, and CCh completely inhibited mycelial growth of Botrytis cinerea at 0.25%. Under artificial inoculation, salts at 1% (immersed or sprayed) showed a variable effect against the pathogen. For natural infection, salt solutions (1%, w/v) were applied according to three strategies: (a) spray (one week) before harvest, (b) immersion after harvest, and (c) combined treatments spray and immersion. The decay incidence of gray mold was evaluated after 30 days at 2 ± 1 °C and 90–95% RH, followed by 7 days of shelf-life at 22 ± 2 °C. All tested salts significantly reduced the decay incidence of gray mold as compared to a water control for the three strategies. The percentages of reduction ranged between 77–100, 91–98, and 61–100% for the preharvest treatment, in combined application, and in the postharvest treatment, respectively. PB and PSo were the most effective salts, completely inhibiting development of gray mold when applied before harvest and as a postharvest treatment. The influence of salts on physical and chemical properties of berry quality including total soluble solids, titratable acidity, pH, color index, weight losses and microbiological profiles was also investigated. New strategies are needed with the critical goal of controlling gray mold of grapes with no fungicide residues. Salts applied just before harvest may be an effective way to minimize gray mold during storage.