Impact of calcium chloride concentrations and storage duration on quality attributes of peach (<Emphasis Type="Italic">Prunus persica</Emphasis>)

To investigate the impact of CaCl₂ concentrations and storage duration on quality of peach (Prunus persica), a research was conducted at postharvest Laboratory, Department of Horticulture, The University of Agriculture, Peshawar, Pakistan during 2012–2013. The experiment was laid out in Completely Randomized Design (CRD) with factorial arrangement repeated three times. The peach fruits (cv. Texas A 69) were harvested at physiological maturity stage from peach orchard, Horticulture Farm. The fruits were dipped in 0, 2 and 4% CaCl₂ solution for 10 min and transferred to cold storage having ±8–10°C with relative humidity of 80–85%. The application of CaCl₂ solution and storage duration significantly influenced the fruit quality of peach fruit. However, the application of CaCl₂ solution significantly reduced weight loss (4.98%), disease incidence (2.08%), total sugars (5.31%), TSS-Acid ratio (16.27), TSS(7.38⁰Brix) and increased the fruit firmness (2.21 kg cm^–2) titratable acidity (0.47%) and Ascorbic acid (5.35 mg/100 g) of peach fruits. The storage duration of peach fruit also significantly affected the fruit quality attributes during storage. The peach fruit stored for 30 days showed less fruit firmness (0.74 kg cm^–2) and titratable acidity (0.31%), Ascorbic acid (4.45 mg/100 g) and increased weight loss (19.74%), disease incidence (16.11%), total sugars (6.07%), TSSAcid ratio (27.62) and TSS(8.54⁰Brix) of peach fruit. Based on the findings of this study, it is concluded that the peach fruit should be treated with 4% CaCl₂ solution to retain the quality attributes for 30 days storage.     

Effects of INA on postharvest blue and green molds and anthracnose decay in citrus fruit

As a synthetic functional analog of salicylic acid, 2,6-dichloroisonicotinic acid(INA) is effective in inducing the host disease resistance of a plant against a pathogen. The effects of INA on controlling postharvest blue and green molds and anthracnose decay and defense-related enzymes on citrus fruits were investigated, and the ascorbic acid of naturally infected citrus flavedo was also measured. Results showed that 1.0 mmol L~(–1) INA treatments significantly reduced blue and green molds and anthracnose decay development on both wound-inoculated fruit and naturally-infected fruit compared with the control fruit. The treatment effectively enhanced the β-1,3-glucanase(GLU), chitinase(CHI), phenylalanine ammonia-lyase(PAL) and peroxidase(POD) activities and the polyphenol oxidase(PPO) in flavedo. The results presented here suggest that INA might be used as a chemical fungicide substitution to control postharvest diseases in citrus fruits.     

Seed Priming Influence on Early Crop Growth,Phenological Development and Yield Performance of Linola (Linum usitatissimum L.)

Reduced early crop growth and limited branching are amongst yield limiting factors of linola. Field response of seed priming treatments viz. 50 mmol L⁻¹ salicylic acid (SA), 2.2% CaCl₂ and 3.3% moringa leaf extract (MLE) including untreated dry and hydropriming controls was evaluated on early crop growth and yield performance of linola. Osmopriming with CaCl₂ reduced emergence time and produced the highest seedling fresh and dry weights including Chl. a contents. Osmopriming with CaCl₂ reduced crop branching and flowering and maturity times and had the maximum plant height, number of branches, tillers, pods and seeds per pod followed by MLE. Increase in seed weight, biological and seed yields was 9.30, 34.16 and 39.49%, harvest index (4.12%) and oil contents (13.39%) for CaCl₂ osmopriming. Positive relationship between emergence and seedling vigor traits, 100-seed weight, seed yield with maturity time, 100-seed weight and seed yield were found. The study concludes that seed osmopriming with CaCl₂ or MLE can play significant role to improve early crop growth and seed yields of linola.     

露娜森和拿敌稳对芒果采后炭疽病的防治效果

为探索芒果花果期喷施杀菌剂而实现防控采后炭疽病的方法,选取露娜森和拿敌稳杀菌剂开展采后炭疽病防治试验。设计每种杀菌剂2个施药剂量梯度,咪鲜胺试验区,另设空白试验,共6个处理,比较各药剂处理间病情指数。试验结果表明,本实验所选用的药剂对芒果花果期的嫩叶、花、幼果未见药害,也不影响芒果的后熟,且采后7天时,花果期喷施1500倍浓度的露娜森的防效与采后浸果咪鲜胺的防效相当、防效达72.73%,货架期可维持7天,750倍浓度拿敌稳次之,对芒果炭疽病的采后储藏期有较好的防治效果,明显延长了芒果的货架期、储藏期。由于露娜森中含有新型的琥珀酸脱氢酶抑制剂——氟吡菌酰胺的原因,其作用机理是抑制了琥珀酸脱氢酶的活性。琥珀酸脱氢酶抑制剂类杀菌剂通过干扰复合体Ⅱ上4个亚基来抑制线粒体的功能,阻止其产生能量,抑制病原菌生长,与咪鲜胺处理的结果一致,具有一定的推广应用价值。     

保鲜剂与保鲜膜在芒果贮藏保鲜中的应用试验

芒果(MangiferaindicaL.)是典型热带水果,七八成熟的果实采后在常温下5～7d,即可完全成熟,而后稍不加控制马上会迅速腐烂。分析其原因有两个:一是果实发生生理病变,如营养失调,过度失水,有毒代谢产物过多积累等,导致果实组织中毒,扰乱果品正常生理;二是病原真菌和细菌浸染,引起果实组织败坏崩解而腐烂。其中后者产生的作用更为严重。急需加强采后保鲜技术研究。笔者试验的目的是研究贵妃芒、台农芒的采后生理及保鲜措施,为芒果保鲜提供技术服务。     

Pre-harvest spraying of oxalic acid improves postharvest quality associated with increase in ascorbic acid and regulation of ethanol fermentation in kiwifruit cv. Bruno during storage

The kiwifruit trees (Actinidia deliciosa cv. Bruno) were sprayed with 5 mmol L^–1 oxalic acid (OA) or water (as control) at 130, 137 or 144 d after full-blossom, and then the fruit were harvested at commercial maturity and stored at room temperature (20±1)°C for 13 d. The effect of pre-harvest spraying of OA on postharvest quality of kiwifruit was evaluated during storage. The OA spraying slowed the increase in soluble solids content (SSC) and decrease in titratable acid (TA), as well as increased contents of ascorbic acid (AsA) and total-AsA accompanied with higher AsA/DHA ratio in kiwifruit during storage. Moreover, the OA spraying significantly reduced the contents of acetaldehyde and ethanol in kiwifruit, along with significant decrease in activities of enzymes involved in ethanol fermentation metabolism during the later period of storage, which was beneficial to control off-flavor associated with over accumulation of ethanol during postharvest. It was suggested that pre-harvest spraying of OA might maintain the postharvest quality of kiwifruit in relation to delay in fruit ripening, AsA maintenance and regulation of ethanol fermentation.     

水杨酸对枇杷冷藏效果的影响*

 以“解放钟”枇杷(Eriobotrya japonica Lindl . cv . Jiefangzhong)果实为试材,研究了水杨酸处理对冷藏(1～5℃)枇杷果实品质及腐烂率的影响。结果表明,采用0.3g/L 水杨酸（SA）浸果20min 处理,可延缓可溶性固形物和可滴定酸含量的下降,抑制果心褐变,降低果实腐烂率的发生,从而延长果实贮藏期。而经0.5g/L SA处理后果实可溶性固形物和可滴定酸含量的下降较快且对果实产生伤害,果实腐烂加重。     

水杨酸处理对猕猴桃细胞壁的影响

为了探究水杨酸处理对猕猴桃果实采后细胞壁代谢的影响,采用水杨酸溶液浸果10 min,常温下((25±2)℃)保存40 d,于0,20,40 d时取样,测定硬度、可溶性固形物、可滴定酸、维生素C等生理指标和细胞壁多糖的含量、单糖组成等指标的变化。结果表明,水杨酸处理金艳猕猴桃果实不但能够很好地减缓果实品质的下降,也可以减缓细胞壁多糖的降解、延长贮藏期。     

外源NO对采后芒果果实低温胁迫后H2O2代谢的影响

一氧化氮（NO）是植物体内重要的信号分子。为了探讨NO对采后芒果低温胁迫后果实过氧化氢（H2O2）及抗氧化酶的影响,分别采用0.08 mmol/L NO供体SNP溶液和30 μL/L NO气体处理采后青芒果果实,并于3℃低温贮藏12 d后,检测芒果果皮和果肉中H2O2含量和相关抗氧化酶的活性。结果表明,外源NO浸泡处理能显著降低低温胁迫后芒果果皮中H2O2水平,提高超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的活性,其中NO对CAT活性的影响最大,可能是外源NO处理调控H2O2水平的关键作用点。NO供体SNP处理效果优于NO气体处理,主要作用部位为芒果果皮。     

草酸—壳聚糖复合处理对采后芒果果实品质及保鲜效果的影响

【目的】探索草酸—壳聚糖复合处理对采后芒果果实品质及保鲜效果的影响,为芒果采后的贮藏保鲜提供理论依据及技术指导。【方法】以台农一号芒果为材料,做以下4种方式处理:1%壳聚糖（Chitosan,CTS）浸泡5 min （CTS处理）,5 mmol/L草酸（Oxalic acid,OA）浸泡10 min （OA处理）,5 mmol/L OA浸泡10 min晾干后再置于1% CTS浸泡5 min （OA-CTS处理）,以及清水浸泡（对照,CK）,各处理晾干后置于20℃冷库贮藏,探讨3种保鲜方式对芒果腐烂率和硬度,可溶性固形物、可滴定酸、多酚、类黄酮和花青素含量,以及过氧化氢酶（CAT）、过氧化物酶（POD）和谷甘光肽还原酶（GR）活性的影响。【结果】贮藏过程中,OA、OA-CTS处理明显抑制花青素含量的积累,OA-CTS处理使其峰值延后4 d。贮藏第5~9 d时,OA和OA-CTS处理诱导果实类黄酮含量的积累;贮藏前13 d,OA-CTS处理诱导CAT活性的升高;贮藏第5、13、21和25 d时,CTS和OA-CTS处理的果实多酚含量显著高于CK （P<0.05,下同）;第21 d时,与CK相比,CTS、OA和OA-CTS处理的硬度分别增大0.7、2.1和1.2 kgf,CTS、OA和OA-CTS处理的可溶性固形物含量分别减少4.9%、1.3%和5.4%（绝对值,下同）,可滴定酸含量分别增加0.40%、0.36%和0.26%,GR活性分别升高0.08、0.10和0.21 U/g;第25 d时,CTS和OA-CTS处理使芒果的腐烂率分别降低0.5%和0.8%,CTS、OA和OA-CTS处理使果实固酸比分别下降51.50、9.41和37.21,CTS和OA处理使CAT活性分别提高2.96和15.87 U/g,OA和OA-CTS处理使POD活性分别升高2.50和3.97 U/g,OA处理使多酚含量减少0.03 U/g。【结论】1%壳聚糖、5 mmol/L草酸及草酸—壳聚糖复合处理均能较好地保持采后芒果果实的感官和营养品质,提高抗氧化能力,延长其贮藏时间,均可用于芒果采后保鲜。     

Effects of Chlorine Dioxide Gas on Postharvest Physiology and Storage Quality of Green Bell Pepper （Capsicum frutescens L. var. Longrum）

The effects of treatment of chlorine dioxide (ClO2) gas on postharvest physiology and preservation quality of green bell peppers were studied. Green bell peppers were collected in bags and treated with 0, 5, 10, 20, and 50 mg L-1 ClO2 gas at 10 ± 0.5℃ for over 40 d, and the changes in postharvest physiology and preservation quality of the peppers were evaluated during the storage. The inhibition of rot of the peppers was observed for all the tested ClO2 gas treatments. The rot rates of the treated samples were 50% lesser than those of the control after day 40 of storage. The highest inhibitory effect was obtained after 50 mg L-1 ClO2 gas treatment, where the peppers did not decay until day 30 and showed only one-fourth of the rot rate of the control at day 40 of storage. The respiratory activity of the peppers was significantly (P ＜ 0.05) inhibited by 20 and 50 mg L-1 ClO2 treatments, whereas no significant effects on respiratory activity were observed with 5 and 10 mg L-1ClO2 treatments (P＞ 0.05). Except for 50 mg L-1 ClO2, malondialdenyde (MDA) contents in the peppers treated with 5,10, or 20 mg L-1 ClO2 were not significantly (P＞0.05) different from those in the control. Degradation of chlorophyll in the peppers was delayed by 5 mg L-1 ClO2, but promoted by 10, 20, or 50 mg L-1 ClO2. The vitamin C content, titratable acidity,and total soluble solids of the peppers treated by all the tested ClO2 gas did not significantly change during the storage.The results suggested that ClO2 gas treatment effectively delayed the postharvest physiological transformation of green peppers, inhibited decay and respiration, maintained some nutritional and sensory quality, and retarded MDA accumulation.     

采前喷洒赤霉素对‘红贵妃’芒果色泽及相关酶活性的影响

以15年生‘红贵妃’果树为试验材料,采前喷洒不同浓度(0,0.3,0.5,1.0,2.0,3.0 g·L~(-1))的赤霉素(gibberellin,GA_3),测定8成熟(80%)果实色泽和相关酶活性的变化。结果表明:随着贮藏时间延长,不同浓度GA_3处理的芒果果实其色泽a*值、类胡萝卜素含量、花青苷含量不断上升,叶绿素含量逐步下降;叶绿素酶活性、苯丙氨酸解氨酶活性与查尔酮异构酶活性逐渐上升。随着贮藏时间的延长,果皮从深绿色到浅绿色再向红黄色转变。与CK相比,0.3,0.5,1.0 g·L~(-1)GA_3处理可以抑制果皮色泽的转变,而2.0,3.0 g·L~(-1)GA_3处理的抑制效果虽显著,但影响后熟芒果的外观品质和风味。综合保鲜效果和外观品质,以1 g·L~(-1)的GA_3溶液处理较为适宜。     

Yield gap and production constraints of mango (Mangifera indica) cropping systems in Tianyang County,China

Mango is an important cash crop in the tropics and subtropics. Determining the yield gap of mango and production constraints can potentially promote the sustainable development of the mango industry. In this study, boundary line analysis based on survey data from 103 smallholder farmers and a yield gap model were used to determine the yield gap and production constraints in mango plantations in the northern mountain, central valley and southern mountains regions of Tianyang County, Guangxi, China. The results indicated that the yield of mango in three representing regions of Tianyang County,Northern Mountains, Central Valley and Southern Mountains, was 18.3, 17.0 and 15.4 t ha~(–1) yr~(–1), with an explainable yield gap of 10.9, 6.1 and 14.8 t ha~(–1) yr~(–1), respectively. Fertilization management, including fertilizer N, P_2O_5 and K_2O application rates, and planting density were the main limiting factors of mango yield in all three regions. In addition, tree age influenced mango yield in the Northern Mountains(11.1%) and Central Valley(11.7%) regions. Irrigation time influenced mango yield in the Northern Mountains(9.9%) and Southern Mountains(12.2%). Based on a scenario analysis, the predicted yield would increase by up to 50%, and fertilizer N use would be reduced by as much as approximately 20%. An improved understanding of production constraints will aid in the development of management strategy measures to increase mango yield.     

NO处理对采后芒果抗氧化酶系统的影响

[目的]探讨NO处理对采后芒果抗氧化酶系统的影响.[方法]以“吉禄”芒果为试验对象,用0.1 mmol/L的外源NO浸泡处理芒果果实30 min,25℃贮藏11d,分析NO处理对芒果果实中过氧化物酶（POD）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）等抗氧化相关酶活性及丙二醛（MDA）含量变化的影响.[结果]NO处理能在一定程度上抑制芒果果实丙二醛含量的增加,并提高超氧化物歧化酶、过氧化物酶、过氧化氢酶和抗坏血酸过氧化物酶的活性,从而延缓了采后芒果果实在贮藏过程中的衰老进程.[结论]研究可为NO用于芒果贮藏保鲜提供理论依据.     

烟草炭疽菌的分子鉴定与检测

克隆并测定烟草炭疽菌r DNA全序列,序列全长2870 bp。序列比对发现,烟草炭疽菌与胶孢炭疽菌的rDNA序列相似性最高,达96.0%~96.2%;从构建的系统关系树也可以看出,烟草炭疽菌与胶孢炭疽菌聚成一个单独的分支,说明烟草炭疽菌与胶孢炭疽菌的亲缘关系最近。因此,结合烟草炭疽菌的形态学特征,可以初步将从贵州烟草分离的烟草炭疽菌鉴定为胶孢炭疽菌(Colletotrichum gloeosporioides)。根据所测烟草炭疽菌的rDNA序列设计特异性引物,不仅可以从8种不同的烟草病原真菌中鉴定出烟草炭疽菌,而且可以从7种炭疽菌中鉴定出烟草炭疽菌。用烟草炭疽菌接种普通烟,以接种发病的病组织总DNA为模板,利用该特异性引物进行PCR扩增,同样可以扩增出特异性条带,表明该方法可用于烟草炭疽菌的鉴定和快速检测。     

Bacterial extracts and bioformulates as a promising control of fruit body rot and root rot in avocado cv. Hass

At least 20–40% of annual losses of avocado crops are caused by pathogenic fungi. The chemical treatments of these diseases are inefficient, cause environmental pollution and are increasingly restricted by international laws. This work aimed to assess the biocontrol capacity of a bacterial extract to protect avocado fruits and plants from pathogen infections. Extracts from the bacterial isolate Serratia sp. ARP5.1 were obtained from liquid fermentations in a biorreactor. A body rot postharvest infection model with Colletotrichum gloeosporioides on fruits was developed. Moreover, packaging conditions were simulated using the bacterial extract and the commercial fungicide prochloraz as a positive control. Additionally, seedlings infections with Phytophthora cinnamomi were performed on two types of avocado(West Indian race and cv. Hass). The Area Under Disease Progress Curve(AUDPC) was recorded using the bacterial extract and a commercial product with fosetyl-aluminium as treatments. The bacterial extract significantly reduced infections by C. gloeosporioides on injured avocado fruits at 31.1 μg mL–1. Intact fruits were also protected against body rot infections at the same concentration and showed no significant differences with the commercial fungicide. On the other hand, AUDPC in the seedlings was significantly reduced with the extract treatment at 3 μg mL–1 compared to the control. However, a possible phytotoxicity effect of the extract was evidenced in the seedlings and confirmed by pathogen recovery and tests on Raphanus sativus seedlings. Finally, formulations of the extracts(emulsion and emulsifiable concentrate) were prepared, and bioactive stability was assessed for 8 wk. The emulsion formulates demonstrated very stable bioactivity against P. cinnamomi. The extract and the emulsion formulate showed promising results for the control of avocado pathogens. New bioproducts based on this type of active principles could be developed for the benefit of avocado industry.     

芒果炭疽病生态位研究

以叶片和果实病情指数为依据,研究了海南省7个芒果品种的炭疽痛生态位.结果表明,芒果炭疽病对叶片和果实的侵染效应差别较小,对时间、空间和营养3资源的利用程度不尽相同.时间生态位宽度指数(平均值)分别为0.117 7和0.263 9,说明芒果炭疽病在时间维上的利用程度小,其发生和发展具有条件性;空间生态位宽度指数(平均值)为0.704 7和0.904 0,病菌能够充分利用各空问资源;营养生态宽度指数为0.666 2和0.579 6.说明病菌可以侵染各品种,但品种间的抗病性有较明显差异,台农1号抗病性较强,红芒6号、凯特和白玉较易感病.     

水杨酸对冷藏期枇杷品质的影响研究

[目的]为枇杷的采后贮藏和运输提供理论依据。[方法]以"大五星"枇杷为试材,用浓度为0.1、0.3、0.5 g/L水杨酸(SA)溶液浸泡枇杷果实20 min后进行冷藏,研究SA处理对枇杷果实冷藏期品质的影响。[结果]与清水处理(对照)相比,0.1 g/L SA处理可明显抑制枇杷果实的腐烂,降低失重率,维持较高的可滴定酸、可溶性固形物和Vc的含量,从而提高枇杷果实贮藏期品质、延长贮藏期;而0.3、0.5 g/L SA处理能增加枇杷果肉冷藏期的硬度,但对其他生理指标的影响不明显。[结论]该研究对研究枇杷的保鲜贮运具有重要意义。     

Melatonin treatment alleviates chilling injury in mango fruit 'Keitt' by modulating proline metabolism under chilling stress

Mangoes often suffer from low temperature-induced chilling injury (CI) during postharvest cold storage.  Therefore, advanced techniques are crucial and in high demand to solve the chilling stress of mango fruit for a higher value.  This study addresses chilling stress modulation by investigating the effects of melatonin treatment on CI, proline metabolism, and related gene expressions of ‘Keitt’ mango during cold storage after dipped in 0 (control), 0.1 (MT1), and 0.2 mmol L^–1 (MT2) melatonin solution for 30 min.  The results revealed that melatonin treatment in MT1 significantly reduced CI development and increased proline content in mango fruit during cold storage compared to the control.  These changes were along with increases in the activity of critical enzymes as well as the expression of encoding genes involved in proline biosynthesis, such as pyrroline-5-carboxylate synthetase (P5CS), pyrroline-5-carboxylate reductase (P5CR), ornithine D-aminotransferase (OAT), P5CS2, P5CR2, and OAT3.  Additionally, proline dehydrogenase (PDH) activity and the expression of the PDH3 gene associated with proline dehydrogenation were lower in MT1-treated mangoes than the controlled group.  Thus, melatonin treatment has regulated proline metabolism resulting in the accumulation of proline, subsequently contributing to enhancing the chilling tolerance of ‘Keitt’ mango fruit.     

1-MCP 处理哈密瓜适宜窗口期的研究

用1-甲基环丙烯（1-MCP）处理采后不同时间间隔西州密25号哈密瓜,研究哈密瓜采后与1-MCP 处理之间的有效间隔,确定1-MCP 处理适宜的窗口期,为其在哈密瓜采后贮运中的应用提供理论依据。哈密瓜采后间隔6,12,24 h,分别用1-MCP 处理,贮藏在室温（25±2）℃条件下,测定果实品质指标。结果表明,1-MCP 处理保持哈密瓜贮藏期可溶性固形物和维生素 C 含量,延缓果实硬度的下降,抑制果皮叶绿素的分解,减少果实的失重和腐烂,抑制了丙二醛的累积。通过对试验结果的比较得出哈密瓜果实在采后12 h 内用1-MCP 处理能够较好的保持果实采后品质。