Induction of Resistance to Penicillium digitatum in Grapefruit by β-Aminobutyric Acid

-Aminobutyric acid (BABA), an inducer of pathogen resistance in plants, induced disease resistance in reproductive parts of the plant, such as grapefruit peel tissue. Application of BABA to specific wound sites on the fruit peel surface induced resistance to Penicillium digitatum, the main postharvest pathogen of citrus fruit, in a concentration-dependent manner, being most effective at 20mM, and rather less effective at either higher or lower concentrations. The effect of BABA in inducing resistance to P. digitatum in the fruit peel surface was local and limited to the vicinity (within 1–2cm) of the BABA-treated site. In addition to inducing pathogen resistance, increasing concentrations of BABA (from 1 to 100mM) also exhibited direct antifungal activity and inhibited P. digitatum spore germination and germ tube elongation in vitro. The induction of resistance to P. digitatum by BABA was accompanied by the activation of various pathogen defense responses in grapefruit peel tissue, including activation of chitinase gene expression and protein accumulation after 48h, and an increase in phenylalanine ammonia lyase (PAL) activity after 72h.     

葡萄柚籽提取物和聚乙烯包装处理 对香椿贮藏期微生物变化的影响

基于香椿因采摘期短、季节性强和极易腐烂变质等问题,以二茬香椿为原料,采用不同浓度的葡萄柚籽提取物(GSE)和聚乙烯(PE)包装对其进行保鲜处理,测定其贮藏期间的菌落总数、霉菌酵母菌数及细菌和真菌的生物多样性.结果表明,0.5％GSE结合PE保鲜膜处理组能够有效地抑制菌落总数以及霉菌酵母菌数的增长;优势细菌门为蓝菌门(Cyanobacteria)和变形菌门(Proteobacteria),优势细菌属为产碱菌属(Alcaligenes)和红色杆菌属(Rubrobacter);优势真菌门为子囊菌门(Ascomycota)和担子菌门(Basidiomycota),优势真菌属为短梗霉属(Aureobasidium)和斯宾塞马丁氏孢菌属(Spencermartinsia).香农指数和主成分分析结果表明,0.5％GSE结合PE保鲜膜处理组的细菌和真菌生物多样性最低,微生物群落更加稳定.     

葡萄柚籽提取物和聚乙烯包装对香椿贮藏品质的影响

香椿（Toona sinensis）的嫩叶和嫩芽营养丰富，风味独特，但香椿属于季节性蔬菜，极易腐烂，严重影响货架期。葡萄柚籽提取物（grapefruit seed extract，GSE）是天然的强抗氧化剂、天然防腐剂。使用0.02 mm厚度的聚乙烯（polyethylene，PE）薄膜包装香椿并利用0.1%、0.3%和0.5%浓度的GSE进行处理，研究不同处理下贮藏期间香椿感官品质与理化指标的影响。结果表明：不同处理均具有一定的保鲜效果。其中，0.5% GSE+PE处理可以显著延缓香椿褐变和腐烂，降低失重率，控制叶绿素含量的升高，抑制呼吸速率和乙烯释放速率。研究结果为香椿的采后保鲜提供了重要的理论依据和实践参考。