Control of lemon postharvest diseases by low-toxicity salts combined with hydrogen peroxide and heat

The effectiveness of potassium sorbate, sodium bicarbonate and potassium phosphite combined with heat and hydrogen peroxide in the presence of CuSO₄ to control major lemon postharvest diseases was investigated on artificially infected fruit. Green and blue molds, which both require wounds for infections to occur, were controlled by combination of hydrogen peroxide followed by inorganic salts, even when the temperature solutions were 25 °C. Control of sour rot was poor with salt solutions alone but significantly improved in treatments including hydrogen peroxide followed by potassium sorbate or sodium bicarbonate at 50 °C. Phomopsis stem-end rot was effectively controlled by potassium sorbate and potassium phosphite at 20 °C, and diplodia stem-end rot was partially controlled only by potassium sorbate. Applications of either potassium sorbate or a sequence of hydrogen peroxide followed by potassium phosphite were the most promising treatments, primarily because they controlled most of the diseases without the need to heat the solutions. These treatments controlled postharvest citrus diseases to useful levels and could be suitable alternative to conventional fungicides, or could be applied with them to improve their performance or to manage fungicide resistant isolates.     

施肥对火棘淀粉和可溶性蛋白含量影响的研究

[目的]为火棘果的进一步开发提供理论依据。[方法]对人工种植的火棘施纯氮0(N0)、23 g/株(N23),P2O5 0(P0)、23 g/株(P23),K2O0(K0)、23 g/株(K23),研究N、P、K对火棘淀粉和可溶性蛋白含量的影响。[结果]不同施肥处理火棘淀粉和可溶性蛋白含量有差异。N0P23K0处理的淀粉含量最高,最低的是N23P23K0;N23P0K0处理的可溶性蛋白含量最高,最低的是N23P23K23。N23P23K0、N0P23K23和N23P0K0处理的蛋白图谱中比其他处理多了一条分子量为51.766 kD的蛋白带。火棘可溶性蛋白的分子量集中在50～63 kD,属于低分子量蛋白。[结论]N、P、K相互作用对火棘淀粉的合成与积累有一定的作用,对蛋白的合成有较大的影响。     

施磷水平对小麦根系生理及籽粒蛋白质含量的影响

为明确磷肥对小麦品质及根系发育的调控效应,以强筋小麦品种郑麦9023、中筋小麦品种周麦18号、弱筋小麦品种郑麦004为材料,研究了3个磷肥水平（0、90、180 kg P₂O₅·hm^-2）对不同筋力型小麦籽粒蛋白质含量和根系数量性状及生理生化特性的影响。结果表明,施磷在不同程度上增加了小麦次生根数,提高了根系活力,降低了根系可溶性糖含量,但高磷（180 kg P₂O₅·hm^-2）并不利于根系生长。3个小麦品种次生根数在籽粒灌浆期均达最高值,其中,郑麦004的单株次生根数和主茎次生根数较多;根系活力在拔节期达到最大值,成熟期降到最低,其中,郑麦9023根系活力较弱;根系可溶性糖含量在冬前达到最大值,其中,周麦18号的根系可溶性糖含量较高。施磷可增加周麦18号和郑麦9023的籽粒蛋白质含量,但降低郑麦004的籽粒蛋白质含量;在中磷（90 kg P₂O₅·hm^-2）条件下,小麦蛋白质产量最高。综合考虑,在本试验条件下,以中磷处理效应最佳。     

UV-C light inactivation kinetics of Penicillium expansum on pear surfaces: Influence on physicochemical and sensory quality during storage

UV-C inactivation kinetic data of Penicillium expansum on intact and wounded pear disks were determined. P. expansum conidia (0.5 mL, 1.6 × 10⁷ CFU/mL) were spot inoculated onto intact and wounded pear tissue with skin (excised disks), treated with UV-C doses ranging 0.101–3.06 kJ/m² at 23 °C and surviving conidia were enumerated. Changes in selected physicochemical parameters and sensory quality following UV-C treatment of whole pears were determined immediately after treatment, and 4 and 8 weeks of storage at 4 °C. A greater UV-C intensity was required for similar inactivation levels of P. expansum populations on wounded pear disks (3.1 kJ/m² for 2.7 log reduction) compared to intact pear disks (1.7 kJ/m² for 2.8 log reduction). No significant difference in % weight loss, or soluble solids content and texture was observed between UV-C treated and untreated pears. However, browning was observed on UV-C treated pear surfaces after 4 and 8 weeks along with changes in flavor and texture. An increase in consumer preference was noticed for the untreated control pears after 4 weeks storage.     

一种检测荷载pGMCSF-SS质粒的 减毒沙门氏菌数的方法学研究

以荷载pGMCSF-SS质粒的减毒沙门氏菌为参考菌，连续培养13h，间隔1h连续采样，用紫外分光光度计检测OD600值，同时用平板计数计算活菌数。根据所测数据，建立细菌对数与细菌浊度之间的直线回归数学模型，即Y=1.5568x+7.0944, R2=0.9543，并对相关关系进行了显著性检测︱r︱>r0.01，表明此回归方程可信度很高。为进一步检测该模型的可靠性，在培养时间内随机取样，检测OD600值，比较利用平板计数与回归方程所得细菌对数Y，二者差异不显著（p>0.05）。通过探讨细菌浊度与细菌计数之间的相关性建立的回归方程，可以有效地克服传统计数方法的不足，便于应用     

Effects of Low Temperature Treatment before Planting on Garlic（Allium sativum L.)Cultivars POD Activity and Soluble Protein Content

以不同熟性7个大蒜品种为试材,研究了播前低温处理对大蒜鳞茎POD活性和可溶性蛋白质含量的影响。结果表明,低温处理后7个品种的植株鳞茎POD活性在鳞茎形成期均低于相应对照,可溶性蛋白质含量变化不同。鳞茎POD 活性和可溶性蛋白质含量均呈降低趋势;晚熟品种鳞茎POD活性呈现高于中、早熟品种的趋势。     

硝酸钾对假俭草抗寒性和草绿期的影响

用硝酸钾(0、2.5、5.0、7.5和10.0 g/L)对盆栽假俭草(Eremochloa ophiuroides(Munro.)Hack)优良品系E-126进行处理,通过测定叶中叶绿素、可溶性糖和脯胺酸的含量及相对电导率,研究其对假俭草抗寒性和绿期的影响,结果表明:在低温条件下,硝酸钾处理的假俭草与对照相比,不仅降低了电导率,提高了叶绿素的含量、抑制了叶绿素的分解,而且提高了可溶性糖、脯胺酸的含量,从而提高了抗寒性.其中效果最好的处理为7.5 g/L,可延长假俭草草绿期12～13 d.     

不同品种高酸苹果的主要品质检测初报

分析了高酸苹果品种澳洲青苹、瑞丹、瑞连娜的外观品质、内在品质和榨汁品质,测定了成熟期果实品质理化指标.试验表明,3个品种的可滴定酸含量均符合果汁加工含酸量要求,其中瑞连娜可滴定酸含量最高,最适合果汁加工.     

翠冠与玉冠梨果实发育过程中色素、糖、酸累积特性研究

为进一步明确不同皮色梨品种果实色素、内在品质成分的变化特性,以褐皮梨新品系玉冠与绿皮梨品种翠冠为试材,测定了果实发育进程中纵横径、果皮与果肉色素含量的动态变化,以及在成熟至采收期间,可滴定酸、可溶性固形物、糖含量的变化特性。结果显示,2品种果实发育均呈"S"型曲线动态变化,果皮与果肉总叶绿素与类胡萝卜素含量及在测定期间的动态变化规律亦无显著差异。在成熟前14d至采收,果实生长趋缓,糖、酸含量急剧变化,2品种表现出各自特点,生产上应针对不同品种的内在品质形成特性,适期采收。     

嫁接对甜瓜果实发育及风味品质的影响

采用白籽南瓜京欣砧3 号为砧木,厚皮甜瓜IVF117 和薄皮甜瓜IVF09 为接穗,研究嫁接对甜瓜果实生长发育、果实中糖含量和成熟果实芳香物质相对含量及种类的影响。结果表明：嫁接显著增加了果实的膨大速度及单瓜质量,促进了果实发育。嫁接降低了成熟甜瓜果实中的葡萄糖、果糖、蔗糖以及总的可溶性糖的含量。嫁接厚皮甜瓜成熟果实中产生7 种特异性物质,占总成分的6.35%,而缺失了自根苗中的14 种物质,占总成分的15.75%。嫁接薄皮甜瓜成熟果实中总芳香物质相对含量降低了24.38 个百分点,其中主要酯类乙酸乙酯的相对含量降低了23.44 个百分点。嫁接甜瓜中芳香物质种类和含量的改变,是导致厚皮甜瓜异香产生、薄皮甜瓜香气变淡的原因。