采前钙处理对木洞杨梅果实采后品质和延缓衰老的影响

用不同浓度CaCl2溶液对木洞杨梅果实进行采前喷钙处理,研究其对果实品质和延缓衰老的影响,达到延长贮藏期的目的。结果表明：钙处理能有效维持果实的硬度,延缓可滴定酸、可溶性固形物、Vc含量的下降;钙处理能显著降低果实的腐烂率、损失率和呼吸强度;钙处理在一定程度上抑制了果实膜透性和丙二醛（MDA）含量的增加,显著抑制超氧化物歧酶（SOD）活性的降低。从而延缓果实成熟衰老进程,较好的保持了果实品质。3种喷钙浓度处理中以 0.25% CaCl2 溶液效果最好     

采后油菜素内酯处理对桃果实常温贮藏 品质的影响

以久保桃果实为试材,采后用5μmol/L油菜素内酯浸泡处理果实10 min,探讨其对果实常温(20℃,相对湿度50%~60%)贮藏品质的影响。结果表明,采后油菜素内酯处理可抑制久保果实质量损失率的增加,降低呼吸强度,延缓果肉硬度的下降,维持较高的抗坏血酸含量,但降低可滴定酸含量。由此表明,油菜素内酯可以延缓常温贮藏期间桃果实的衰老速度,保持较高的品质。     

油菜素内酯对枣果贮藏过程中的病害及衰老的作用

本文研究了油菜素内酯（Brs）对于由青霉菌均引起的枣果青霉病以及枣果采后衰老的作用。试验结果表明,浓度为5μm的油菜素内酯即可抑制青霉病的发展,并可提高几种抗性酶的活性,如苯丙氨酸解氨酶、多酚氧化酶、过氧化氢酶和超氧化物岐化酶。然而,油莱素内酯对于离体青霉菌并没有直接的抑制活性,油莱素内酯可通过减少乙烯生成及提高枣果品质来显著延缓其采后衰老。     

水稻内源油菜素甾醇对施氮量的响应及其对颖花退化的调控作用

为探明油菜素甾醇(brassinosteroids,BRs)是否介导氮肥对水稻颖花退化的影响。水稻品种扬稻6号和甬优2640种植于盆钵,全生育期设置3种施氮水平,观察了不同氮肥处理下水稻减数分裂期幼穗中氮含量、BRs、过氧化氢(H2O2)和总抗氧化能力(totalantioxidantcapacity,T-AOC)水平及其与颖花退化的关系。结果表明,颖花退化率的降低与稻穗中增加的24-表油菜素甾酮(24-epicastasterone,24-epiCS)和28-高油菜素内酯(28-homobrassinolide,28-homBL)含量密切相关。当稻穗的氮含量为1.25%时,幼穗中BRs(24-epiCS和28-homBL)含量显著增加,颖花退化率显著降低。稻穗中T-AOC水平与BRs含量变化趋势相同,且均与水稻颖花退化率显著负相关,而H_2O_2含量与BRs含量和T-AOC变化趋势相反。施用外源BRs(24-epiCS或28-homBL)可显著提高稻穗中内源BRs(24-epiCS和28-homBL)含量与T-AOC水平,并显著降低稻穗中H_2O_2含量和颖花退化率,施用BRs合成抑制剂则效果相反。表明BRs可以介导氮肥对水稻颖花退化的调控,在减数分裂期适宜的稻穗含氮量(1.25%)可有效提高幼穗中的BRs含量,并通过提高抗氧化能力来抑制颖花退化。     

采后油菜素内酯处理对久保桃果实活性氧代谢的影响

以久保桃果实为试材,研究采后油菜素内酯(BL)浸泡处理对桃果实活性氧代谢的影响。结果表明,采后5μmol/L BL处理提高了桃果实超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性,但抑制了贮藏前期过氧化氢酶(CAT)活性的升高。此外,BL处理抑制了丙二醛(MDA)含量的上升,提高了果实总抗氧化能力。由此表明,采后BL处理延缓桃果实衰老与提高果实抗氧化保护系统性能有关。     

壳聚糖-山梨酸复合涂膜对宣城圆枣保鲜效果的影响

针对鲜食红枣成熟后贮藏期短,商品性会随贮藏期延长而降低等问题,以宣城圆枣为试材,采用5个浓度(0.1%、0.25%、0.5%、1.0%、1.5%)壳聚糖与浓度为0.1%的山梨酸混合,配制成复合保鲜液,对其进行涂膜保鲜处理。结果表明:在4℃条件下,壳聚糖-山梨酸复合涂膜处理在一定程度上能延缓宣城圆枣果实失重率与腐烂率上升的速度,同时抑制硬度及VC含量的下降,从而延缓果实的成熟衰老进程,提高贮藏品质,延长货架期。通过对各项果实品质指标数据的综合分析得出,复合涂膜溶液的最佳使用浓度为0.25%壳聚糖+0.1%山梨酸。     

1-MCP与乙烯吸收剂对猕猴桃果实采后生理及品质的影响

[目的]为解决1-MCP和乙烯吸收剂在猕猴桃贮藏保鲜应用上的问题。[方法]以徐香猕猴桃为试材,研究了1-MCP和乙烯吸收剂对果实贮藏期及货架期果实成熟衰老和品质的影响。[结果]结果表明,1-MCP和乙烯吸收剂均显著地抑制了果实乙烯释放、呼吸作用和脂氧合酶(LOX)活性,使果实硬度下降和营养物质消耗趋缓,延长了果实贮藏期和货架期。1-MCP抑制了猕猴桃果实贮藏期和货架期酯类物质的合成,并在货架期积累了较多的醛类和醇类物质,对果实的风味品质有一定不利影响;乙烯吸收剂处理的果实货架期内酯类物质含量上升较快因而具有较好的风味品质。[结论]综合评价,乙烯吸收剂处理可更好地保持猕猴桃贮藏品质。     

贝莱斯芽孢杆菌对采后葡萄果实贮藏品质的影响

通过研究贝莱斯芽孢杆菌对葡萄果实贮藏品质的影响,为提高葡萄果实采后贮藏稳定性,延长贮藏期提供科学依据。以“玫瑰香”葡萄为试材,用拮抗菌溶液(TP-1)处理葡萄果实,以无菌水处理作为对照,处理后将果实分别置于25℃与4℃条件下贮藏,测定葡萄果实贮藏期间腐烂率、失重率、可溶性固形物含量、相对电导率、硬度、果皮色度、VC含量以及可滴定酸含量的变化。结果表明：整个贮藏期间,贝莱斯芽孢杆菌TP-1处理可以有效降低葡萄果实腐烂率,常温贮藏25 d时,腐烂率仅为42%,低于其他处理组;葡萄果实失重率在贮藏期内大幅上升,但贝莱斯芽孢杆菌TP-1处理果实失重率均低于对照组,在常温贮藏25 d时,效果最明显;葡萄果实硬度在贮藏期内逐渐下降,常温贮藏15～25 d果实硬度下降最快,贮藏25 d时,贝莱斯芽孢杆菌TP-1处理组果实硬度最高,为1.21 kg/cm²。此外,贝莱斯芽孢杆菌TP-1处理还可抑制葡萄果实相对电导率的上升,维持果皮色度和较高水平的可溶性固形物含量,延缓可滴定酸和VC降解。贝莱斯芽孢杆菌TP-1处理组能有效维持葡萄果实贮藏品质。     

壳聚糖涂膜对芒果采后品质及生理特性的影响

为了探讨壳聚糖涂膜保持芒果采后品质的相关生理机制,以‘台农1号’芒果(Mangifera indica L.‘Tainong No.1’)为材料,研究了1.0%壳聚糖涂膜处理对芒果在常温(28~30℃)贮藏条件下果实品质及生理特性的影响。结果表明,与对照相比,壳聚糖涂膜处理显著降低了果实的失重率和病果率,延缓了果皮颜色的转黄,保持较高的果实硬度;并且,壳聚糖涂膜有效保持了果实品质,能够显著延缓芒果可滴定酸(TA)含量的降低和可溶性固形物(TSS)含量的升高,维持芒果果实较高的Vc含量;同时,壳聚糖涂膜也提高了芒果果实贮藏后期超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性,并抑制MDA含量的积累,降低膜脂过氧化程度,从而延缓了采后芒果的后熟衰老进程。     

被子及蕨类植物中的BRs

油菜素甾醇(BRs)是一类具有高生理活性的植物激素,油菜素内酯(BL)和油菜素甾酮(CS)是其中活性较强的两种存在形式。CS作为BL的前体,同样在植物中广泛存在,且其为蕨类植物中BRs的主要存在形式。BRs特异的合成途径从CR起始,经过多种酶的催化得到CS,存在AtBR6ox2时才可进一步得到BL。而后,其大致的信号传导过程得到了解析。BRs作为第六大类植物内源性激素,在植物生长发育过程中发挥着无可取代的作用,能促进植物细胞的伸长与分裂、影响光形态建成、调节植物育性和抗逆性等,而这些功能的实现都得益于BR信号途径下游转录因子对应的靶基因的表达。以上相关内容在被子植物中都取得了较大的研究进展,而在蕨类植物中却鲜少报道。因此,本研究从BRs的生物合成、信号转导和发育调控等3个方面对被子植物和蕨类植物进行对比阐述。     

DTA-6对大豆花荚脱落纤维素酶和GmAC基因表达的调控

叶面喷施生长调节剂(PGRs)可以调控大豆花荚脱落。2012-2013年在大庆林甸县黑龙江八一农垦大学试验基地采用大田小区试验,R1期对大豆绥农28(SN28)、垦丰16 (KF16)和合丰50 (HF50)分别叶面喷施DTA-6调节剂,对调控花荚离区脱落纤维素酶(GmAC)基因相对表达量、荚脱落纤维素酶(AC)活性、花荚脱落率和产量进行了研究。结果表明：DTA-6抑制大豆花荚离区GmAC基因相对表达量,最大可达51% (±CK%);大豆荚的AC活性能够在喷药后阶段性地被降低,在不同品种上增加和降低存在差异;能够显著降低花荚脱落率(P<0.05);能够显著增加产量(P<0.05)。植物生长调节剂DTA-6是通过降低花荚离区GmAC基因相对表达量,调节AC活性,从而减少植株的花荚脱落率,以实现对产量的调控。     

A method for evaluating fruit abscission potential of grapes and cherry tomato clusters

Abscission is an important postharvest factor for table grapes and cluster cherry tomatoes. There are methods to measure the individual fruit removal force but until now there has been no objective method to study the abscission at a whole cluster level. The working principle of the instrument is that a cluster is attached to a rod which is allowed to fall freely for a pre-determined distance; as the rod stops, the momentum of the berries is converted to detachment force applied to the abscission zone of each berry. The abscission potential can be evaluated as a percentage of fruit detached from cluster under given conditions. The instrument was constructed for robust and adjustable experimental use. It is shown that the abscission percentage for both table grapes and cluster cherry tomatoes was proportional to the free-fall distance. By using the instrument, we showed that the abscission potential of cluster cherry tomatoes was low during the first 2 weeks of storage and that it increased thereafter. Storage of cluster cherry tomatoes at 7 °C resulted in significantly less abscission than at 12 °C, as assessed either by manual shaking or by using the instrument. Treatment of grapes with the cytokinin-like compound forchlorfenthuron at 4 mg L⁻¹ during the early stages of fruit development resulted in significant reduction in abscission potential. These results demonstrate that the method can be used as a reliable experimental tool for objective evaluation of abscission potential.     

高压静电场诱导采后葡萄果实总黄烷-3-醇积累模型构建

高压静电场能够诱导采后葡萄果实多酚类物质积累,为实现优化和准确调控葡萄果实总黄烷-3-醇积累量,构建葡萄果实总黄烷-3-醇含量在高压静电场作用下随时间变化的连续模型.首先,以酿酒葡萄赤霞珠为试材,选用-2 kV/cm高压静电场,分别等时间间隔和随机时间间隔对总黄烷-3-醇含量取样,采用DMACA法获得两组数据;其次,根...     

植物器官脱落相关激素和酶的研究进展

研究植物器官脱落机制对调控植物生长和促进农产品产量和品质具有重要意义。植物器官脱落是一个复杂的生理过程,脱落发生部位离区形成后能够通过感受外界环境因子以及自身生长因子等脱落信号来调节植物细胞内生理生化反应从而完成器官脱落。本文主要从生理学和分子学方面对植物器官脱落的激素调控机制（生长素、乙烯、脱落酸）和酶调控机制（果胶酶、纤维素酶、过氧化物酶）进行综述,以期为进一步研究植物器官的脱落机理提供参考。     

1-MCP partially alleviates dehydration-induced abscission in cut leaves of the fern Nephrolepis cordifolia

Fern leaves, also called fronds, are often used in bouquets. Leaves of the sword fern (Nephrolepis cordifolia) consist of a central vascular tissue, with numerous leaflets (pinnae) at each side. Leaves that have been cut and immediately placed in water show abscission of the pinnae, starting from about day 4 of vase life, with 50% pinnae abscission on day 13. The onset of pinnae abscission was hastened by a period of dehydration (3, 6, 9 or 12 h at 25 °C). The time to 50% pinnae abscission was between 7.0 and 4.7 days after 3 h and 12 h of dehydration, respectively. Dehydration treatments might induce air emboli in the xylem, but in these experiments did not inhibit water uptake. Dehydration did increase the rate of ethylene production of the cut leaves throughout vase life. A 3 h treatment with 1-MCP at concentrations of 200 or 300 nL L^?1 prior to the period of dehydration reduced the rate of ethylene production and reduced the rate of abscission. 1-MCP treatments were also effective if given after the period of dehydration. The data show that pinnae abscission limits the vase life of cut leaves of the sword fern, and that a short period of water stress drastically increases the rate of abscission. The increase in pinnae abscission was correlated with an increase in ethylene production. As 1-MCP alleviated the effect of dehydration on pinnae abscission, the dehydration effect involved ethylene perception. The data suggest that a small water stress induced an autocatalytic rise in ethylene production which was the direct cause of the increase in pinnae abscission.     

Effects of new packaging solutions on physico-chemical,nutritional and aromatic characteristics of red raspberries (Rubus idaeus L.) in postharvest storage

Postharvest life of raspberries (Rubus idaeus L.) is limited due to their high respiration rate, loss of firmness and freshness and susceptibility to fruit rot. The aim of this research was to evaluate the effects of various packaging solutions on physico-chemical, nutritional and aromatic properties of raspberries during storage at +4 °C up to 7 days. Plastic materials with low (LDPE) and high (LDPE/EVOH/LDPE) gas barrier, a biopolymeric film (PLA) with medium gas barrier and micro perforated stretch film (PVC) were used. The packaging material modified the composition of the atmosphere in the package, which depended on the combined action of the respiration activity of the fruit and the permeability of the material. Results showed that the most sensitive parameters for the assessment of raspberry decay were percentage of damaged berries, weight loss, fruit softening and the aromatic profile development, evaluated by an electronic nose; these parameters showed significant changes during storage and were influenced by the packing material. All samples showed a clear loss of firmness after 4 days of storage, which was maximally reduced in the case of LDPE/EVOH/LDPE and PLA packages. Raspberries stored in PVC packaging material had an aromatic development similar to the control, whereas berries stored in the medium and high barrier materials showed important changes in the aromatic profile, reflecting anaerobic metabolism of fruit. Soluble solids, pH, total phenolics and ascorbic acid did not change significantly; changes in colour and total anthocyanins were observed, with differences depending on the kind of packaging.     

Studies of postharvest berry abscission of ‘Kyoho’ table grapes during cold storage and high oxygen atmospheres

The effects of high O₂ on catabolic enzymes and anatomical structure in abscission zones, fruit detachment force (FDF), and berry drop of grapes were investigated. ‘Kyoho’ table grapes (Vitis vinifera x V. labrusca) were subjected to air or 80% O₂ at 0 °C in 95% relative humidity for 60 days. During storage, separation occurred at the berry-pedicel indentation and the abscission layer extended gradually from lateral phloem towards the whole phloem and pith, forming intercellular cavities and leading to berry drop. FDF declined steadily accompanied by an increase in berry drop. Grape abscission was correlated to the increases in activity of hydrolases, in particular cellulase (Cx) and polygalacturonase (PG), in abscission zones. In contrast to air storage, high O₂ inhibited Cx, PG and pectinesterase (PE) activity and the reverse for peroxidase (POD), decreased the degree of swelling and distorting of the abscission cell walls, and tended to keep berry adherence strength high and reduced berry drop. The inhibitory mechanism of high O₂ on berry drop possibly could be explained by the fact that disassembly of the abscission zone cells was delayed by a synergistic impact on degradation enzymes whose activities were affected by high O₂ levels.     

Inheritance of sugars and acids in berries of grape (Vitis vinifera L.)

Inheritance patterns for table grape sugars and organic acids were investigated on three cross offspring populations during two successive years. Glucose and fructose were the predominant sugars in progeny berries with only trace amounts of sucrose. Total sugar content showed additive inheritance and the broad-sense heritability ranged from 0.61 to 0.84. The means of progeny sugar content were lower than mean parent values. Inheritance of malic acid was strongly additive and the broad-sense heritability varied from 0.73 to 0.89. The means of progeny malic acid content were higher than mean parent values. Tartaric acid was mainly controlled by non-additive effect and the broad-sense heritability varied from 0.59 to 0.84. The means of progeny tartaric acid content were lower than mean parent values. Inheritance of the total acid content was strongly additive and was mainly influenced by malic acid. The broad-sense heritability of total acid varied from 0.53 to 0.90.     

The Relationship Between Sugar-Nitrogen Ratio and Reproductive Organs Abscission in Faba Bean (Vicia Faba L.)

The changes of soluble sugar and total nitrogen content of vegetative organs in faba bean, sugar-nitrogen ratio, abscission of reproductive organs and the relationship between sugar-nitrogen ratio and abscission probability were studied using the faba bean cultivar Xichang Dabai . Plants were field grown in 1986, 1988 and 1990. The lands were separated into high yield land, middling yield land and low yield land according to grain yield at maturing stage. The soluble sugar content in vegetative organs (leaf + stem) was greatest from branching to floral initiation stages and pod-set to filling grain stages, and distinctly decreased at the onset of bloom and maturing stages. The total N content was greatest at branching stage, and gradually decreased with growth. In general, the sugar and total N contents in high yield lands were greatest, followed by that in middling yield and low yield lands. The sugar-nitrogen ratio varied depending on the soluble sugar content.
Average yield on high yield lands, middling yield land and low yield land across 3 years were 5048.77 kg/ha, 3744.01 kg/ha and 2378.22 kg/ha, respectively. The total reproductive organs abscission exceeded 90 % of total flower buds. Abscission probability averaged across 3 yield lands and 3 years were 21.6 %, 84.0 % and 32.8 % in flower buds, flowers, and pods, respectively. Node 7–12 of canopy produced more flowers, and fewer flowers and pods were produced in the upper and lower regions. Photosynthate supply has been implicated in control of abscission. Faba bean reproductive organs abscission probability increased with the sugar-nitrogen ratio of vegetative organs decreasing. It seemed that the soluble sugar content influenced significantly the shedding rate during flowering and pod-growing stages.     

Ethylene production by gynoecium and receptacle is associated with sepal abscission in cut Delphinium flowers

Delphinium flowers are sensitive to ethylene, and exposure to ethylene is known to accelerate sepal abscission. The relationship of ethylene to sepal abscission in cut Delphinium flowers was investigated. The gynoecium and receptacle each contributed to climacteric-like increases in ethylene production whereas the sepals, petals and stamens did not. 1-Aminocyclopropane-1-carboxylic acid (ACC) concentration, ACC synthase and ACC oxidase activities in the gynoecium and receptacle increased in the senescing flowers. Wounding of the gynoecium or receptacle accelerated abscission of sepals, which was accompanied by a marked increase in ethylene production. Accelerated sepal abscission was counteracted by treatment with silver thiosulphate complex (STS), an inhibitor of ethylene action. The results of this study show that ethylene produced by the gynoecium and receptacle is closely associated with sepal abscission in cut Delphinium flowers.