采前喷施赤霉素对‘苹果梨’常温贮藏期黑皮病的防控效果

为探讨果实发育期喷施赤霉素对‘苹果梨’常温贮藏期间黑皮病的防控效果,在幼果期、果实膨大期和果实成熟期连续3次用50 mg/L赤霉素喷施果实及周边叶片,测定采收时和贮藏期间果实细胞膜完整性、总酚含量以及主要抗氧化酶和氧化酶活性的变化。结果表明:采前喷施赤霉素有效降低了‘苹果梨’常温贮藏期间的黑皮指数,果实贮藏40 d后发病率仅为同期对照的一半;采前喷施赤霉素处理还降低了果实贮藏期间总酚含量以及多酚氧化酶(PPO)活性,维持细胞膜的完整性,提高超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性。说明于梨果实发育期喷施赤霉素可通过维持果实细胞膜完整性、提高抗氧化酶活性以及抑制总酚积累和多酚氧化酶活性来减轻‘苹果梨’常温贮藏期间的黑皮病。     

赤霉素处理对‘无核白’葡萄糖酸比的影响

为提高‘无核白’葡萄可溶性固形物含量、调整总酸含量、控制产量、调节糖酸比,改善‘无核白’葡萄主要商品品质,根据葡萄果实生长发育过程中因酸作为呼吸基质氧化分解,有机酸含量减少、糖含量增加的原理,于2012年5-8月,在新疆吐鲁番市红柳河园艺场‘无核白’葡萄园内,采用低浓度多梯度赤霉素处理‘无核白’葡萄,在提高总酸的基础上,提高可溶性固形物含量,调整总酸含量,调节糖酸比.其中赤霉素处理浓度依次为70、70、90 g/kg,能使‘无核白’葡萄可溶性固形物含量在8月中旬达23％,总酸0.612％,糖酸比为37.58,产量达到28102.95kg/hm2.能较好地调节糖酸比,显著提高‘无核白’葡萄商品品质.     

赤霉素对露地栽培月季‘卡罗拉’生长发育的影响

通过喷施不同浓度的GA_3(以喷水为对照),记录初花和谢花日期,于盛花期时调查花枝长、花柄长、株高及叶片长宽比等生长指标,研究赤霉素处理对露地栽培切花月季‘卡罗拉’生长发育的影响。结果表明,不同浓度GA_3处理对其株高、花枝长、花柄长均具有不同程度的促进作用。300 mg·L~(-1) GA_3处理,平均花枝最长,叶片长宽比值最大;300和400 mg·L~(-1) GA_3处理,平均花柄最长;500 mg·L~(-1) GA_3处理,平均株高最高。对300 mg·L~(-1) GA_3处理的植株材料进行扫描电镜观察及RT-PCR分析结果发现,RhGA2ox、RhGA20ox、RhGA_3ox及RhGID1基因表达上调,表明促进了体内GA_3的积累,诱导了生长素合成相关基因的表达,导致植物细胞伸长、细胞体积增大,因而促进植株增高、叶片变长;开花相关基因RhAP1、RhKSN和RhSOC1的表达先上升后下降;RhAP1、RhFT和RhSOC1的表达,尤其是开花素基因RhFT在21 d时的高水平表达可能造成比对照提早开花;而RhKSN基因高水平表达抑制了开花基因表达导致开花期延长。     

赤霉素对芹菜采后衰老的影响

芹菜在衰老过程中，叶绿素不断降解，过氧化物酶活性升高而ＳＯＤ活性逐渐降低，与此同时，膜脂质过氧化作用逐渐增强，表现为脂质过氧化产物──丙二醛不断积累，导致细胞膜透性逐渐增大。外源赤霉素（ＧＡ）处理可以明显抑制芹菜衰老过程中的脂质过氧化作用，延缓芹菜的衰老。，达极显著水平。图２各处理ＰＯ０、ＳＯＤ活性的变化（叶柄）在：ＳＯＤ活性是以初始值为１００的相对活性。２．４ＧＡ处理芹菜丙二醛（ＭＤＡ）含量的变化图３各处理叶柄ＭＤＡ含量的变化由图３可以看出，作为膜脂过氧化产物之一──丙二醛，在芹菜衰老过程中呈累积性上升，ＧＡ处理，可以极显著地（α＝０．０ｌ）抑制ＭＤＡ积累，２．５芹菜衰老过程中细胞膜透性的变化表２ＧＡ处理叶柄细胞膜透性的变化相对电导率％由表２的结果可以看出，随着实验期的延长，芹菜的细胞膜透性逐渐增大，ＧＡ处理，可显著地降低膜透性的变化，保护膜结构的完整性。３讨论与结论目前，关于植物衰老的研究表明，膜脂过氧化对植物的衰老具有促进与加强作用［４］。本试验的结果表明，芹菜衰老过程中，在叶绿素降解的同时，ＳＯＤ活性下降，脂质过氧化产物──ＭＤＡ积累，导致细胞内膜系统的连锁性破坏。并且越到后期这种破坏作用越为明显，     

外源赤霉素处理对采后香蕉生理生化的影响

为了延缓香蕉腐败变质，以采后香蕉果实为试材，采用50 mg/L赤霉素(GA₃)溶液浸泡处理，以蒸馏水浸泡为对照，相同条件下贮藏，研究贮藏期间GA₃对果实硬度、色差、褐变面积，可溶性固形物、抗坏血酸、丙二醛含量，相对电导率，多酚氧化酶、过氧化物酶、过氧化氢酶以及抗坏血酸过氧化物酶活性的影响。结果表明，GA₃有效地延缓香蕉果实褐变，保持果实硬度和色泽，抑制可溶性固形物和抗坏血酸含量减少，多酚氧化酶和过氧化物酶活性较对照(蒸馏水)分别降低49.98%和35.70%,过氧化氢酶和抗坏血酸过氧化物酶活性较对照(蒸馏水)分别提高43.37%和38.41%,显著抑制电导率上升和丙二醛积累，维持果皮细胞膜结构和功能。说明GA₃可有效延缓香蕉衰老进程，保持果实品质，延长果实贮藏期。     

‘脆枣’采后赤霉素处理对其生理生化的影响

 ‘脆枣’采后用GA3 30 mg·L^-1 处理，较好地保持了硬度，抑制了乙醛、乙醇含量的上升以及乙醇脱氢酶和多酚氧化酶的活性，降低了呼吸强度和乙烯释放速率，推迟了酒化和褐变的发生。     

采后热、钙处理对‘苹果梨’组织衰老的影响

该文以延边地区主栽品种‘苹果梨’为试材,探索在不同贮藏方式下,热、钙处理对采后‘苹果梨’果实组织衰老程度的影响。结果表明,无论在冷藏还是窖藏条件下,各种处理均能降低细胞膜透性,其中钙处理效应最显著;抑制PPO活性增加的速度和SOD活性下降的速度。冷藏与各处理结合处理效果更明显。     

采前高浓度赤霉素处理对“贵妃”杧果实色泽发育的抑制效应

以10年生"贵妃"杧植株为材料,设置赤霉素(GA_3)0、0.5、1.0、2.0和3.0 g/L等处理,分别于盛花期、幼果期和果实膨大期进行喷洒,比较不同处理对采后杧果果实色泽变化的影响。结果表明,与对照相比,不同浓度GA_3处理对果皮色度a~*值均具有明显影响,浓度越高,抑制a~*值增大的效果越显著;GA_3处理可以显著抑制果皮叶绿素的降解,降低类胡萝卜素及花青素的合成;高浓度GA_3对叶绿素酶、查尔酮异构酶活性增加、5-氨基乙酰脱氢酶活性的降低具有明显的抑制效果。说明采前GA_3处理可以抑制采后"贵妃"杧果皮色泽转变,浓度越高对果皮转色的抑制效果越显著。     

早熟砂梨‘翠冠’hmgr基因家族两成员的表达与货架期黑皮病关系的研究

 以砂梨黑皮病易感品种‘翠冠’果实为材料,克隆获得了调控α-法尼烯合成的关键限速酶3-羟基-3-甲基戊二酸单酰辅酶A还原酶（HMGR）基因家族中的两个成员Pphmgr1和Pphmgr2。Pphmgr1开放阅读框为1 827 bp,编码由609个氨基酸残基组成的蛋白;Pphmgr2开放阅读框为1 707 bp,编码由569个氨基酸残基组成的蛋白。序列比对结果显示：‘翠冠’PpHMGR1和PpHMGR2与苹果果实的MdHMGR1和MdHMGR2蛋白的同源性分别达到90%和98%。在采后货架期28~32 ℃条件下,乙烯受体抑制剂1-MCP 可明显抑制果实呼吸率,减缓乙烯释放,显著降低果皮中α-法尼烯及其氧化产物共轭三烯的含量,减少黑皮病发病率并减轻发病程度。半定量RT-PCR结果显示1-MCP处理后果皮中Pphmgr2的表达受到显著抑制,但是Pphmgr1的表达几乎不受影响。     

Addition of salicylic acid to nutrient solution combined with postharvest treatments (hot water,salicylic acid,and calcium dipping) improved postharvest fruit quality of strawberry

This experiment was conducted to study the effect of salicylic acid addition to nutrient solution and different postharvest treatments on fruit quality of strawberry cv. Camarosa after 7 days at 2 °C. Plants were irrigated with two complete nutrient solutions, with salicylic acid (0.03 mM) or without salicylic acid as the control. Fruits were then treated with eight different postharvest treatments (25 °C water, 45 °C water, 25 °C or 45 °C water containing CaCl₂ (1%), 25 °C or 45 °C water containing salicylic acid (2 mM) and 25 °C or 45 °C water containing both CaCl₂ (1%) and salicylic acid (2 mM)). Fruits which received SA in their nutrient solution had less weight loss and decay and higher firmness. All of the postharvest treatments improved fruit quality characteristics. Fruits dipped in salicylic acid solution had less weight loss, decay and a* (redness) and higher firmness and hue angle than control. Heat treated fruits had less decay and a* and higher hue angle than control. Fruits dipped in CaCl₂ solution had less weight loss, decay and a* and higher firmness than control. Combination of the three postharvest treatments improved firmness, decay, weight loss and vitamin C.     

Maintenance of fresh boysenberry fruit quality with UV-C light and heat treatments combined with low storage temperature

Summary

Mature boysenberries (Rubus hybrid) were harvested, heat-treated (45°C for 1 or 3 h or 47°C for 1 h) or exposed to UV-C light (2.3, 4.6 or 9.2 kJ m^–2), and stored at 20°C for 2 d. Fruit treated with 9.2 kJ m^–2 or 45°C for 1 h showed less damaged drupelets per fruit and/or remained firmer than untreated fruit after 2 d. Those treatments were selected for further analyses. In another experiment, boysenberries were either UV-C (9.2 kJ m^–2) or heat-treated (45°C for 1 h) and stored either at 20°C for 1 d or at 0°C for 4 d before transfer to 20°C for 1 d. Both UV-C and heat treatments reduced softening and/or fruit damage. Treated fruit had lower respiration rates and anthocyanin leakage than control fruit suggesting greater tissue integrity. Titratable acidity, pH, total sugar content and antioxidant activity in treated fruit showed fewer changes than in control fruit when stored at 20°C for 1 d. Results suggest that heat or UV-C treatment, alone or in combination with refrigerated storage, may be a useful non-chemical mean of maintaining boysenberry fruit quality and extending postharvest life.     

Relation of peel damage in citrus fruit to wind climate in orchard and its control

Peel damage originated by wind is the main abiotic cause of citrus fruit discards for export in Uruguay. Natural windbreaks such as Eucalyptus and Casuarinas have not been effective in reducing it. This research was carried out during three years in a citrus orchard situated in the coastal plain of Uruguay (35° SL). The purpose of this work was to study wind climate inside the orchard, fruit seasonal sensitivity, basal leaf effect on the onset and evolution of peel damage, and the efficiency of artificial windbreaks to reduce fruit discard of ‘Ellendale’ tangor. Average wind velocity in the orchard did not exceed 5 m s⁻¹. First peel scars were evident two weeks after petal fall and damaged fruit percentage importantly increased during the first stage of fruit growth. Low energy vortexes caused almost permanent friction between basal leaves and the developing fruitlets growing in their axil. Removal of the basal leaf decreased significantly wind damaged fruit. Natural wind flow modification through the use of semi-porous artificial windbreak nets (5 cm by 10 cm mesh) modified low energy vortexes and increased significantly the percentage of export quality fruit. We conclude that this type of net is more efficient than natural windbreaks or classical nets to reduce wind damage in citrus fruit.     

Effect of low temperatures on pulp browning and endogenous abscisic acid and ethylene concentrations in peach (Prunus persica L.) fruit during post-harvest storage

Summary

Changes in the severity of pulp browning, endogenous abscisic acid (ABA) and ethylene concentrations, and related gene expression in peach (Prunus persica L. ‘Bayuecui’) fruit stored at the biological freezing-point temperature (BFT; 1ºC), at 4ºC, or at room temperature (20ºC; as a control) were investigated.The results showed that fruit stored at room temperature showed climacteric changes in ethylene and ABA concentrations and in levels of expression of the corresponding ethylene synthetase genes (PpACS1, PpACO1) and the gene for a key enzyme of ABA synthesis (PpNCED), concomitant with a significant decrease in fruit firmness and an increase in juice yield. Meanwhile, two sucrose synthase genes (PpSUS1 and PpSUS2) were expressed at relatively low levels. However, fruit firmness decreased slightly and chilling injury (CI) increased significantly 40 d after storage (DAS) at 4ºC, with a significant accumulation of proline [from 8.33 µg g^–1 (at t = 0 d) to 9.125 µg g^–1 (at t = 40 d)]. In contrast, fruit firmness decreased slowly and pulp browning increased slightly 80 DAS at the BFT ( 1ºC), with a lower accumulation of proline than in fruit stored at 4ºC. The concentrations of soluble sugars and titratable acidity decreased during storage at 1ºC, 4ºC, or 20ºC, but there was a peak of soluble sugars at a late stage of storage at the BFT ( 1ºC). The fruit browning index was significantly and positively correlated (R ² = 0.967) with ABA concentration. The decrease in ABA concentration in cold-stored fruit (at both 1ºC and 4ºC) inhibited ethylene production. Moreover, there was no significant correlation between CI in fruit and ethylene production. In conclusion, the decrease in ABA concentration reduced ethylene concentrations and inhibited the development of pulp browning, which resulted in an improved taste, but crisper fruit, when fruit were stored at the BFT (–1ºC).     

香蕉果皮2个HSP70基因片段的克隆及其在热激和冷藏过程中的表达

温度逆境胁迫可以诱导热激蛋白的表达,而热激处理能够减轻果实冷害。为了探讨温度逆境对香蕉热激蛋白基因表达的调控、辨析香蕉热激蛋白基因的表达与果实冷害的关系,采用同源序列法分离了香蕉果皮HSP70基因序列-根据已经报道的HSP70基因的氨基酸保守序列设计引物、以香蕉果皮总RNA为模板,用RT-PCR方法克隆香蕉的HSP70 cDNA,Northern杂交分析该基因在不同贮藏温度下的表达特征。结果得到2个序列不同的HSP70基因片段,分别命名为Ma-HSP70-1和Ma-HSP70-2,Ma-HSP70-1和Ma-HSP70-2之间的碱基同源性为86.9%,氨基酸同源性为97.1%。Northern杂交的结果表明,38℃短期热激处理诱导了Ma-HSP70-2基因的表达,低温冷藏能使2个基因的表达增强。并初步认为Ma-HSP70可能与香蕉果实耐冷性有关。     

A comparison of the combined effect of water stress and crop load on fruit growth during different phenological stages in young peach trees.

Summary

The combined effect of fruit load and water stress on fruit water content and dry-matter accumulation was analysed for three phenological stages of fruit growth. Irrigation treatments were no irrigation during Stage I (NI-SI), Stage II (NI-SII), or Stage III (NI-SIII) compared with a fully irrigated control. Three thinning treatments were imposed within each irrigation treatment resulting in fruit loads ranging from low to high. Fruit harvests at the end of Stage I, II and III were used to determine total tree fruit fresh and dry matter after each stage of fruit development. Fruit water accumulation was highly sensitive to the effect of water stress at high fruit loads in all fruit developmental phases, but reductions in fruit water content were more apparent during Stages II and III than during Stage I. On the other hand, fruit dry-matter accumulation was relatively insensitive to water stress at any fruit load level and developmental stage. However, reductions in dry-matter accumulation were obtained during Stage III from those trees that were not irrigated during Stage I (NISI). Since these reductions occurred only for mid-to-high fruit load conditions, the decreases in fruit growth during Stage III appeared to be related to a carbon source limitation. The possible reasons for this source limitation are discussed.     

Change of heart function and its relationship with AMS during acute high-altitude exposure at 3 658 m in Chongqing soldiers

AIM: To observe the cardiac function during high-altitude exposure in Chongqing soldiers and to discuss its relationship with acute mountain sickness (AMS) by echocardiography. METHODS: The changes of heart function were evaluated during acute high-altitude exposure (3 658 m, 3 d) in 42 healthy young male soldiers by echocardiography. At the same time, the heart rate, blood pressure, blood oxygen saturation, and the incidence of AMS after high-altitude exposure were observed and recorded. RESULTS: Three days after arrival at 3 658 m, the left atrial end-systolic dimension (LADs), left ventricular end-diastolic dimension (LVDd) and right atrial end-systolic dimension were significantly decreased, but the right ventricular outflow tract diameter, pulmonary artery dimension, ejection fraction, cardiac output (CO), pulmonary arterial systolic pressure (PASP) and mean pulmonary arterial pressure were significantly increased compared with the baseline levels in all subjects. The mitral peak E velocity was significantly reduced (P<0.05). A total of 42 healthy young men were recruited and divided into AMS group with 15 subjects and non-AMS group with 27 subjects by Lake Louise scoring after high-altitude exposure. The cardiac function in the plain showed that aortic sinus diameter and LVDd in AMS group were significantly smaller, and PASP was significantly higher than those in non-AMS group. After high-altitude exposure, the LADs in AMS group was significantly smaller than that in non-AMS group (P<0.05). AMS scores and CO in the plain showed significant negative correlation (r=-0.3814, P<0.05). CONCLUSION: Upon acute high-altitude exposure, right ventricular functions of the young male soldiers are damaged with the compensation of the left ventricular functions. Using echocardiography to observe PASP and CO may be helpful for screening the susceptible people of AMS in the plain.