小国光苹果树冠喷布反光剂对果温及果实硬度的影响

小国光苹果树冠喷布反光剂,能明显地降低树冠外围果的果面温度2~5℃,中午前后降温效果最大。对树冠内膛果和园区降温作用不明显,可以减轻小国光裂果程度,不能增加成熟果的硬度。     

辣椒果实成熟过程中硬度及相关生理生化指标的变化

选用2个不同硬度的辣椒品系,在果实成熟的不同时期测定其果肉硬度变化,并测定了与硬度相关的原果胶、果胶和纤维素的含量以及促进细胞壁物质分解的PME,PG,纤维素酶和β_半乳糖苷酶等水解酶的活性。结果表明:果实硬度在转色期最大,随着果实成熟,可溶性果胶含量增加,纤维素含量从转色期开始基本呈下降趋势,从幼果期到转色期PME酶的活性呈上升趋势,529品系酶活性在转色期达到最大,585品系在绿熟期酶活性达到最大值。2个品系的PG酶活性不断上升并在红熟期达到最大值。纤维素酶的活性也呈上升趋势并在转色期达到最大值。2个品系的半乳糖苷酶活性在红熟期达到最大值。辣椒果实成熟软化过程中,其硬度的变化与果胶、纤维素等物质的变化有显著相关性,而这些物质的变化又与促进这些物质水解的细胞壁水解酶活性的变化相一致。在果实成熟的不同时期,这些硬度的相关生理生化指标可以反映出果实的硬度特点,在耐贮运辣椒育种过程中有一定参考价值。     

O-酰基化丝氨酸的合成及其对樱桃番茄乙烯合成量和果实硬度的影响

通过L-丝氨酸与不同的酰氯在室温下反应,合成了8个未见文献报道的乙烯合成抑制剂O-酰基化丝氨酸（2a~2h）,其结构通过核磁共振氢谱、碳谱及高分辨质谱确证。以氨乙氧乙烯基甘氨酸（aminoethoxyvinylglycine,AVG）为阳性对照,测定了目标化合物对樱桃番茄Lycopersivon esculentum Mill.乙烯合成量和果实硬度的影响,同时运用分子对接的方法分析了目标化合物与番茄1-氨基环丙烷羧酸（1-aminocyclopropane-1-carboxylic acid, ACC）合成酶（ACS, 1IAY）可能的结合模式。结果显示:大部分目标化合物具有延缓樱桃番茄果实软化和抑制乙烯合成的作用,其中化合物2c和2h效果较为突出。用2c和2h处理番茄后第5天,与空白对照相比,果实硬度分别提高27.62%和40.04%,均与AVG处理无显著性差异;2c和2h对乙烯合成量的抑制率分别达71.89%和53.28%,其中2c处理的抑制效果显著优于AVG处理。分子对接方法分析结果表明:化合物2c与番茄ACS酶活性空腔的氨基酸残基有较好的相互作用,2c的羧基可与Ala54和Arg412的氨基形成氢键,从而占据ACS酶的活性空腔。O-酰基化丝氨酸类化合物结构简单,容易获取,对乙烯合成抑制剂的开发具有推动作用。     

Plant oil emulsion modifies internal atmosphere, delays fruit ripening, and inhibits internal browning in Chinese pears

'Laiyang Chili’ and ‘Ya Li’ (Pyrus bertschneideri Reld) pears were treated with 3, 6, and 9% emulsions of commercial or refined (reduced -tocopherol levels) plant (soybean, corn, peanut, linseed, and cottonseed) oils at harvest an stored at 0°C for 6 months. Effects of oil treatments on ethylene production, respiration, fruit firmness, fruit color, soluble solid content (SSC), titratable acids (TA), internal browning (IB), and internal CO₂, O₂, and ethanol were studied. At the same concentration, oil treatments induced similar responses regardless of their sources or their -tocopherol concentrations. In both cultivars, ethylene production and respiration in fruit treated with 9% oils were lower in early storage and higher in late storage than that in the controls. Oils at 6% reduced IB, at 9% inhibited IB completely, and at 3% was not effective after 6 months at 0°C and 7 days at 20°C. Plant oil treatment maintained fruit color, firmness, SSC, and TA in a concentration-dependent manner during storage. In the first 4 months storage, 9% corn oil-treated fruit contained similar partial pressure of CO₂ and O₂ as the controls. After 5 months storage, oil-treated fruit contained higher partial pressure of CO₂ and lower levels of O₂ than the controls. When held at 20°C for 7 days, changes of internal CO₂ and O₂ were slower but partial pressure of CO₂ were higher, and O₂ were lower, in 9% corn oil-treated fruit than in the controls. Internal ethanol was not affected by oil treatment compared with control, either during storage or 7 days at 20°C. No off-flavor was detected in either oil-treated and control fruit by sensory evaluation.     

Calcium and Potassium Foliar Sprays Affect Fruit Skin Color,Quality Attributes,and Mineral Nutrient Concentrations of ‘Red Delicious’ Apples

This study was conducted to evaluate the influences of foliar spray of potassium (K), calcium (Ca), and their combination on the fruit red skin color and quality attributes of ‘Red Delicious’ apple under conditions of south central Iran with warm and dry summer, where low and high temperature differences are low. The trees were sprayed five times using 5 g L^–1 calcium chloride (CaCl₂) at 3-week intervals starting from 3 weeks after full bloom and three times (at 9, 12, and 15 weeks after full bloom) using 2.5 g L^–1 K sources [potassium chloride (KCl), potassium sulfate (K₂SO₄), and potassium nitrate (KNO₃)] during two growing seasons in 2013 and 2014. Anthocyanin, some physicochemical attributes, and fruit mineral concentrations were measured at harvest. Results showed that spraying with K, CaCl₂, and their combinations significantly increased fruit weight, sugar and anthocyanin concentrations, firmness, and K uptake. A combined foliar application of CaCl₂ and each of the K sources was more effective on the improvement of fruit color, firmness, fruit K and Ca uptake, and K/Ca ratio as compared to the case when either K or Ca was applied alone.     

海沃德猕猴桃货架期预测模型的建立

为建立海沃德猕猴桃货架期品质变化动力学模型,以实现对海沃德猕猴桃货架期的预测。本试验将经0.5 μL·L^-1 1-甲基环丙烯(1-MCP)处理(处理组)与不处理(对照组)的猕猴桃于0、4、15、25℃条件下贮藏,测定其硬度、可溶性固形物含量、可滴定酸含量、Vc含量;并基于Arrhenius理论建立货架期预测模型,选取20℃样本对该模型进行验证。结果表明,1-MCP对试验设置温度条件下贮藏的海沃德猕猴桃硬度、可滴定酸含量和Vc含量的降低以及可溶性固形物含量的升高均有一定的延缓作用;同时对其硬度和Vc含量变化情况进行拟合,比较拟合后的反应速率常数k,发现温度越高Vc含量和硬度变化越快。比较零级反应和一级反应线性回归决定系数R²可知,对照组和处理组Vc含量变化动力学方程遵循一级反应动力学,对照组R²≥0.97,处理组R²≥0.94;对照组和处理组硬度含量变化动力学方程遵循零级反应动力学,对照组R²≥0.96,处理组R²≥0.92。对照组硬度下降及Vc含量下降的lnk和1/T的R²>0.98,处理组硬度下降及Vc含量下降的lnk和1/T的R²>0.89。将预测值和实测值进行比较,结果显示,对照组猕猴桃货架期预测值和实测值相对误差均在±10%以内。综上表明,用硬度变化预测猕猴桃货架期,操作简单,相对误差较低。本研究结果在猕猴桃贮藏、销售中具有较好的应用价值。     

猕猴桃果实软化过程中细胞壁多糖物质含量与果胶降解相关酶活性变化

为研究不同贮藏温度下不同品种猕猴桃果实软化过程中细胞壁多糖物质降解特性,以及相关果胶降解酶对猕猴桃果实软化进程的影响,测定25℃和4℃贮藏过程中徐香、金丽、晚绿猕猴桃果实的硬度、细胞壁多糖物质含量和果胶降解相关酶活性,并对其进行相关性分析。结果表明,3个品种猕猴桃果实软化过程中半纤维素、纤维素和共价型果胶(covalent soluble pectin, CSP)含量不断降低,水溶性果胶(water soluble pectin, WSP)含量不断增加,而离子结合型果胶(ionic soluble pectin, ISP)含量相对稳定。晚绿猕猴桃各细胞壁多糖组分含量变化速度最快,金丽次之,徐香最慢。4℃贮藏延缓了猕猴桃果实细胞壁多糖物质的降解。相关性分析结果表明,3个品种猕猴桃果实硬度与WSP含量之间均呈显著(P<0.05)负相关,与CSP、半纤维素、纤维素含量之间呈显著正相关。果胶降解酶活性测定结果显示,25℃贮藏前期,晚绿猕猴桃内切多聚半乳糖醛酸酶(endo-polygalacturonase, PG)和β-半乳糖苷酶(β-galactosidase,β-Gal)活性显著高于...     

番茄果实硬度与相关性状间的相关及通径分析

选用本地主栽品种及引进品种,对影响番茄果实硬度的6个指标与硬度进行相关及通径分析。结果表明：纤维素含量和原果胶含量对番茄果实硬度的影响最大,这两个指标是影响硬度的最主要因素。因此在耐储运育种过程中,可将试验材料果实中所含纤维素含量和原果胶含量作为主要的选择指标,提高育种效率,缩短育种周期。     

长采收期桃果实硬度变化与相关激素含量关系的研究

为探讨长采收期桃-双久红果实成熟前后硬度变化与相关内源激素的关系,以普通桃品种—川中岛为对照,在果实成熟前后各20d对其果肉硬度和内源IAA、ABA、CTK、GA3的含量和乙烯释放量进行了测定。结果表明:随着果实的成熟,川中岛果实的硬度迅速下降,双久红果实的硬度则一直保持较高的水平;川中岛果实的乙烯释放量在成熟后5d出现高峰,而双久红则一直处在较低的水平;川中岛桃果肉中IAA、ABA含量、ABA/IAA值均明显高于双久红的,ABA含量与果实硬度呈显著负相关;随成熟度的加大,两类型桃果肉中CTK、GA3含量都呈下降趋势,但双久红桃果肉中的CTK、GA3含量明显高于川中岛的。     

床垫软硬度对不同体型人群体压分布的影响

人体体型特征和床垫的软硬度是影响床垫使用舒适性的重要因素。运用人体体压分布测试系统,探究不同软硬度的床垫对仰侧卧姿势下瘦型、中等体型和胖型3种体型受试者体压分布的影响。结果发现,仰侧卧时,瘦型、中等体型和胖型体型受试者肩部、腰部和臀部的接触面积变化趋势一致,均呈现增大趋势。且仰卧下三体型受试者各部位的平均压力的整体变化趋势大致相同,侧卧时仅瘦型和中等体型受试者三部位的平均压力变化趋势大体一致。另外仰卧时床垫硬度的变化对胖型受试者腰部和臀部平均压力影响较大,对瘦型受试者的体压分布面积指数影响较大,对中等体型受试者腰部平均压力影响最小。侧卧时,床垫硬度的变化对胖型受试者腰部的平均压力影响较为显著,对中等体型受试者的三部位平均压力影响最小。