金秋梨果实发育中生长速率及主要营养成分的变化

通过对金秋梨果实发育过程中果实生长速率、可溶性糖、有机酸、维生素C、可溶性固形物、可食部分和含水量的测定,系统分析了它们在整个生长发育过程中的动态变化。果实生长速率有三个高峰:一个在花后40d,一个在花后82d,一个在花后131d;还原糖与非还原糖含量的变化趋势在花后110d前基本一致,但在花后110d后恰好相反,还原糖含量下降,非还原糖含量上升;有机酸含量在花后124d前逐渐升高,花后124d以后逐渐降低;维生素C含量呈V形的变化曲线,花后96d前逐渐降低,以后逐渐升高;可溶性固形物、可食部分和含水量在果实成熟过程中呈缓慢增长趋势。     

金秋梨果实发育过程中生长速率及主要营养成分的变化

通过对金秋梨果实发育过程中果实生长速率、可溶性糖、有机酸、维生素C、可溶性固形物、可食部分和含水量的测定,系统分析了它们在整个生长发育过程中的动态变化。果实生长速率有三个高峰：一个在花后40d,一个在花后82d,一个在花后131d;还原糖与非还原糖含量的变化趋势在花后110d前基本一致,但在花后110d后恰好相反,还原糖含量下降,非还原糖含量上升;有机酸含量在花后124d前逐渐升高,花后124d以后逐渐降低;维生素C含量呈V形的变化曲线,花后96d前逐渐降低,以后逐渐升高;可溶性固形物、可食部分和含水量在果实成熟过程中呈缓慢增长趋势。     

弱光对西瓜植株生长及果实发育的影响

为明确弱光下西瓜果实难以正常膨大的问题,以西瓜‘苏蜜8号’为试材,通过田间遮阴模拟弱光试验,研究弱光对西瓜植株生长、果实发育的影响。结果表明,弱光对西瓜植株生长的影响从遮光处理开始就一直存在;授粉后的3~15天为西瓜果实快速膨大期,也是弱光影响西瓜果实膨大的关键时期。弱光能显著降低植株的株高、茎粗、叶数和叶大小,并能显著抑制植株光合作用和干鲜物质的积累。弱光使西瓜果肉细胞变小,数目变少;抑制西瓜果肉的细胞核内复制,进而影响西瓜果实的正常膨大。本研究可为西瓜栽培光环境管理和抗弱光栽培技术的研究及应用提供科学依据。     

脐橙果实生长高峰期追肥效应研究

根据脐橙果实生长发育规律,在每次生长高峰期前５－７ｄ,通过一次叶面追肥和根浇肥水处理,结果表明,朋娜、纽荷尔、脐血橙对照相比,分别增产１９．８７％,１６．５７％,１２．９３％;特级、一级、二级果分别提高９％,１１．６％,１１．８％;梨汁率分别提高８．３０％、７．１８％、８．６４５％;全糖分别提高１．０５％,１．３％、０．７６％;可溶性固形物分别提高１．１％、１．４％、０．９％能显著地减少裂果,控制     

金光杏梅果实生长动态观察研究

研究结果表明,金光杏梅果实生长发育动态呈“慢—快—慢—快—慢”的“3S”型曲线,整个发育过程可分为5个时期：幼果缓慢生长期、果实第一次迅速生长期、果实第二次缓慢生长期、果实第二次迅速生长期和果实熟前缓慢生长期。果实第二次缓慢生长期与果实硬核期相吻合,果实第一次迅速生长期和第二次迅速生长期是果实增长的两个关键时期。果实纵、横、侧径和果肉厚度与果实鲜重和体积变化曲线极为相似,经相关分析,果实纵、横、侧径和果肉厚度与果实鲜重的相关系数分别为0.9421**、0.9442**、0.9413**和0.9843**,与     

草莓果实重要性状动态规律研究

为了弄清草莓的果实生长发育规律以及营养成分的变化动态规律,本试验以达赛莱克特、石莓4号、石莓5号和石莓6号为试材,研究了草莓果实从谢花后3d到成熟果实生长发育规律和主要营养成分的变化规律。结果表明:果实纵横径在整个生长发育过程中一直是平稳增长;不同品种果实重量和体积均在花后15d左右开始迅速膨大;含糖量在草莓果实发育过程中总体上呈上升趋势,从白果期至成熟迅速增加;果实白果前可滴定酸呈增长趋势,白果期后开始下降;在果实的发育过程中维生素C含量表现出上升的趋势,至转红期达到最大,成熟时略有降低。     

不同修剪方法对油蟠桃生长及果实品质的影响

2011—2014年,以‘紫月’、‘新月’、‘美月’油蟠桃新品种为试材,进行长枝修剪与传统修剪比较试验,研究不同修剪方法对油蟠桃叶片光合速率、树体生长、各类果枝、1年生枝条萌发情况以及坐果率和产量、果实品质的影响。结果表明:油蟠桃长枝修剪后叶片的光合速率明显提高;翌年萌发的1年生枝中,15~30 cm果枝数量明显高于传统修剪方法;长果枝数量减少,中果枝、短果枝、花束枝数量明显增加,徒长枝数量相差不大。第1次、第3次生理落果后,长枝修剪方法的坐果率高于传统修剪。长枝修剪后的单株产量、单果重均高于传统修剪。在果实品质方面,长枝修剪后,可溶性固形物含量、优质果率高于传统修剪。     

芝麻杂交种生长动态优势的研究

本试验探讨雄性不育二系杂交种豫芝９号生长动态优势，以以亲和豫芝４号为对照，用Ｌｏｇｉｓｔｉｃ生长方程描述其器官生长及干物质积累等１０个怀状的增长过程。比较结果表明，豫芝９号生长发育过程具有的前快后缓有效生长量大的特点。前期持续时间短、中期各器官生长及干物质合成速度愉，形态建成早。各器民干重的ＧＲ１、ＧＲ２和ＧＲｇ与产量显著上关。生长后期即灌浆成熟期持续时间长，根系与生殖器这干物质积累快，盯应ＧＥ３     

金光杏梅果实生长动态观察初报

研究结果表明,金光杏梅果实生长发育动态呈“慢-快-慢-快-慢”的“3S”型曲线．整个发育过程可分为5个时期:幼果缓慢生长期、果实第一次迅速生长期、果实第二次缓慢生长期、果实第二次迅速生长期和果实熟前缓慢生长期。果实第二次缓慢生长期与果实硬核期相吻合,果实第一次迅速生长期和第二次迅速生长期是果实增长的两个关键时期。果实纵、横、侧径和果肉厚度与果实鲜重和体积变化曲线极为相似,经相关分析,果实纵、横、侧径和果肉厚度与果实鲜重的相关系数分别为0．9421**、0．9442**、0．9413**和0．9843**,与果实体积的相关系数分别为0．9391**、0．9462**、0．9373**和0．9824**,均呈极显著相关,说明它们是同步增长的。果核的生长发育动态呈“快-慢-停”的近“厂”型曲线,谢花后31d以前是迅速生长期;31d后进入缓慢生长期并开始硬化、变色:至59d达到固有大小和颜色,硬化结束,59d后停止生长。     

新型饲草玉米生长动态及收割期的研究

对新型饲草玉米不同生长阶段的生长速度、物质积累与分配进行了研究,并对其营养价值进行评定。结果表明,新型饲草玉米生长动态符合Logistic模型,经历了慢—快—慢—快—慢的变化过程;从分蘖期至吐丝期,生物量和茎/叶比值增加,但适口性和营养价值降低,抽雄期后降低更为迅速;其中总能（GE）、消化能（DE）、代谢能（ME）和可消化养分总量（TDN）在孕穗期或抽雄始期最高;抽雄始期鲜草产量和干物质产量分别达101.4 t hm^-2和18.35 t hm^-2,粗蛋白（CP）、粗纤维（CF）、粗脂肪（EE）、粗灰分（CA）和无氮浸出物（NFE）含量分别为14.2%、24.3%、3.9%、6.3%和51.3%,产草量和营养价值均较高。综合分析表明,为同时获得较高物质产量和营养价值,饲草玉米在抽雄始期收割最佳。     

Identification and genetic characterization of an ethylene-dependent polygalacturonase from apricot fruit

During fruit ripening a loss of firmness occurs, which is a key factor limiting postharvest life. In apricot, Prunus armeniaca L., a wide range of fruit firmness at commercial maturity has been observed in different cultivars. Endopolygalacturonase (endoPG) activity has been reported to be associated with differences in firmness in many fruit species, but never in apricot. In this paper, we reported the identification of an apricot cDNA (PaPG) coding for an endoPG-like protein with 393 amino acids. Protein sequence comparison with known polygalacturonases (PGs) revealed that multiple features as conserved domains and functional residues and a predicted signal peptide were present in PaPG. Moreover, a phylogenetic analysis of this and other plant PGs placed PaPG into a clade containing endoPGs expressed in fruit, abscission and dehiscence zones without a propeptide sequence, very close to PRF5 from peach (Prunus persica L. Batsch). PaPG gene expression increased during postharvest storage of the fruit, correlating with fruit softening and ethylene release, and it responded to exogenous ethylene treatments. We localized the PaPG gene in apricot linkage group 4 after genetic mapping based on SNP analysis, in a position apparently syntenic to the PRF5 locus from peach. Results obtained offer genetic evidence supporting the hypothesis that PaPG and PRF5 are orthologous genes, and consequently position PaPG as a gene of interest for studies on fruit softening in apricot, and contribute to the development of molecular tools for breeding apricots with longer shelf life.     

UV-C inactivation of Escherichia coli and dose uniformity on apricot fruit in a commercial setting

A UV-C treatment system (two treatment chambers connected by an inclined belt to rotate apricots between chambers) was tested in a commercial setting. Escherichia coli ATCC 25922, used as a surrogate for E. coli O157:H7 to determine the system's antimicrobial efficacy, was inoculated onto fruit surfaces at a population of 6.8 log CFU/fruit. UV-C dosage was evaluated by attaching film dosimeters to six fixed locations on each apricot. Results suggested that reduction of inoculated E. coli ATCC 25922 populations on the apricot fruit by UV-C treatment was small (only 0.5–0.7 logs). There were large variations in UV-C doses among varying apricot surface locations. Approximately 1/3 of apricots had individual surfaces receiving less than 0.2 kJ m⁻² UV-C exposure, even though fruit received, on average, more than 1 kJ m⁻². Low reductions of E. coli may be attributed, in part, to non-uniform UV-C exposure. This study demonstrates the need to use a fruit rotation device more capable of delivering uniform UV-C dosage to the surface of apricots for inactivating bacteria in a commercial setting.     

Effect of fruit load on oil yield components and dynamics of fruit growth and oil accumulation in olive (Olea europaea L.)

Olive oil yield and its components (fruit number, average fruit weight and fruit oil concentration) depend on crop load and source–sink ratios as affected by environmental conditions, management and the alternate bearing typical of the species. The aims of this work were to: (i) establish quantitative relationships between oil yield and its components as affected by fruit load in a high-yielding production system, (ii) analyse the dynamics of fruit weight and fruit oil concentration in terms of rates and durations, and (iii) explore the relationships between the dynamics of oil and water in fruit. In a fully irrigated olive orchard in Mendoza (32° S), Argentina, cv. Arbequina trees with similar crown volume and three fruit loads (3-fold range) were monitored during two seasons. Oil yield was positively associated with both fruit number and fruit fresh weight, but not with fruit oil concentration. Across seasons and fruit loads, fruit yield increased linearly with fruit number at ～1.5 kg per thousand fruit and reached a maximum ～60 kg tree^?1 (or 25 t ha^?1) at a fruit load of 32,700 fruit tree^?1. The fruit filling rate was affected by fruit load, while the duration of fruit growth and the dynamics of oil and water concentration were unaffected by fruit load. Fruit water concentration reached a minimum at the onset of Stage III of fruit growth, which was marked by a rapid increase in oil concentration. Fruit fresh weight and oil weight increased with source–sink ratio from ～0.5 up to a threshold ～2 m³ crown per thousand fruit. In contrast, a 8-fold range of source–sink ratio did not affect fruit oil concentration.     

Soluble sugars and carboxylic acids in ripe apricot fruit as parameters for distinguishing different cultivars

Major sugar and carboxylic acid components in apricot flesh fruits were detected and quantified. Fifty-one genotypes including clones growing in France, Spain, Italy, Greece and USA, belonging to the INRA germ plasm collection has been evaluated. Principal component analysis (PCA) has been performed to study correlation among fruit quality measurements and to interpret relationships between genotypes as a tool for germ plasm characterization. A marked variation in malic and citric acid content has been observed and PCA revealed clusters of apricot genotypes for the malic/citric ratio content. A good correlation between sugar component and refractometer index (r = 0.83) has been detected. The wide range of diversity in malic and citric acid content in apricot germ plasm makes it possible to breed and select genotypes with improved flavour on the basis of superior phenotypes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phenotypic diversity and relationships of fruit quality traits in apricot (Prunus armeniaca L.) germplasm

Fruit quality attributes were studied for two consecutive years in forty-three apricot cultivars and selections grown in a Mediterranean climate. Physical parameters (weight, size, flesh and skin colour, percentage of blush, firmness and percentage of dry matter), chemical parameters (total soluble solids content and acidity) and sensory parameters (attractiveness, taste, aroma and texture) were evaluated. A high variability was found in the set of the evaluated apricot genotypes and significant differences were found among them in all studied quality attributes. Year-by-year variations were observed for some pomological traits such as harvest date, flesh colour, fruit weight, firmness and soluble solids content. A high correlation was found among some apricot quality attributes. In addition, principal component analysis (PCA) made it possible to establish similar groups of genotypes depending on their quality characteristics as well as to study relationships among pomological traits in the set of apricot genotypes evaluated.     

Diverse dynamics in agroecological transitions on fruit tree farms

Agroecological transition refers to the adoption by farmers of practices based on on-farm biological processes rather than imported or non-renewable inputs. Drawing from a comprehensive survey of 31 diversified farms cultivating citrus on Réunion Island (Indian Ocean, France), this study aims to understand the diverse dynamics in farmers’ agroecological transitions and to identify the factors and processes driving farmers’ choices. The analysis considers both the current protection, fertilization and weed control practices implemented by farmers in their orchards and the trajectories of change they have followed over the last thirty years. Orchard management was categorized according to the kind of inputs mobilized (i.e., “synthetic inputs”, “alternative off-farm inputs” and “alternative on-farm inputs”). Diverse managements were observed, targeting security, autonomy, ecology or simplicity. The six types of practice trajectories identified illustrate the diverse and incremental nature of agroecological transition. Drawing from these results, drivers of alternative practice adoption and lock-in effects in synthetic input reliance were characterized. Internal drivers, depending directly on the farmer and his/her farm, included the characteristics of the orchard and its environment, the labor force, and the farmer’s environmental concerns. External drivers included local citrus markets, public legislation, access to extension services, the organization of input supply and the social environment. The combination of these internal and external drivers at the farm level makes each farm relatively unique. However, three factors determine the main differences in practices: the marketing channel used, the farmer’s environmental objectives, and the farmer’s economic behavior, which is linked to the weight of the crop activity in farm revenue. Understanding farmers’ points of view and decisions regarding agroecological transition deserves the attention of scientists, agricultural advisors and policy makers when designing innovative cropping systems, new support methodologies and incentives to respond effectively to farmers’ objectives and contexts of action.     

Effect of harvest maturity and cold storage on correlations between fruit properties during ripening of apricot (Prunus armeniaca)

Apricots (Prunus armeniaca) were held in air storage at 0 °C and ripened at 20 °C, or ripened at 20 °C straight after harvest, and changes in fruit quality quantified using postharvest and sensory evaluations. Maturity at harvest significantly affected flesh firmness and other quality factors. Mealiness and gel formation only developed in fruit that had been stored at low (0 °C) temperatures. Mealiness did not develop until firmness dropped below approximately 20 N, whereas gel formation began to develop when firmness was as high as 35 N. Development of mealiness and loss of juiciness were correlated; however, slight mealiness was perceived when fruit were still considered juicy. Specific cultivar-related differences were evident in the changes in firmness and development of gel formation during and after cold storage. Fruit were less liked by the sensory panel when firmness dropped below 20 N, as juiciness decreased and mealiness and gel formation increased. Cell wall studies showed changes in yields of water-soluble and CDTA (trans-1,2-cyclohexanediamine tetraacetic acid)-soluble pectin. In fruit ripened after cold storage, mealiness and gel formation was accompanied by an increase in water-soluble pectin and an increase in CDTA-soluble pectin, whereas in apricots ripened straight after harvest, water-soluble pectin increased but CDTA-soluble pectin slightly decreased. All fruit, regardless of maturity or having chilling disorders or not, fitted the same correlation between firmness and uronic acid content of water-soluble pectin, but no pattern was evident for CDTA-soluble pectin. We concluded that the increasing solubilisation of pectin was a major feature of fruit softening in apricot, whereas the differences in CDTA-soluble pectin may reflect differences in strength of cell adhesion.     

北方烤烟钾氯含量及其与吸食品质的关系研究

【研究目的】为明确我国北方地区烟叶钾、氯含量基本状况及其与卷烟燃烧性、吸食品质的关系;【方法】采集北方5省295份烟叶样品,分析其主要化学成分并鉴定其感官质量,另测定50份烟叶样品的自由燃烧速率;【结果】东北三省烟叶氧化钾含量、氯离子含量、钾氯比的离散度都比较大,辽蒙、山东、黑吉烟叶氧化钾、氯离子含量存在明显地域性差异;氯离子含量是制约辽蒙烟区烟叶吸食品质提高的首要因素,主要影响烟叶香气质、香气量、杂气、余味4项指标得分;氯离子含量是影响山东烟区烟叶香气量、刺激性、评吸质量3项指标得分的首要影响因素;氯离子含量对烟叶燃烧性起决定性的负作用;【结论】辽蒙地区烟叶氧化钾、氯、钾氯比适宜范围为＞1.0%、＜0.6%、＞1.5;山东地区烟叶氯、钾氯比适宜范围分别为为＜0.6%、＞3。     

Longkong fruit abscission and its control

Longkong fruit abscission was found to be sensitive to external ethylene at concentrations as low as 0.05 μL L⁻¹. Ethylene induced fruit drop at the junction between the main peduncle and the calyx, at a clear abscission zone. Fruit drop at the junction between calyx and the fruit, however depended on an external force. There may or may not be an abscission zone at this site. Dipping longkong fruit in 200 μL L⁻¹ NAA solution delayed fruit abscission and slightly reduced ethylene production. NAA application was also found to reduce the effect of external ethylene treatment. Applications of 1 μL L⁻¹ 1-MCP for 6 h minimized the effect of external ethylene and almost doubled storage life of longkong. The combination of NAA and 1-MCP treatment did not give a synergistic effect.     

Studies on habit of flowering and its relation to shape of fruit in an inbred line of watermelon,Citrullus vulgaris schrad.

Attempts have been made to describe the interaction between the shape of fruit and habit of flowering in two watermelon plants found in the multiplication plot of a new variety. The first plant Gol-43-1 had staminate and perfect flowers; the shape of fruit was oblate to oblong. The other, Gol-43-2, bore pistillate, staminate and perfect flowers; the shape of fruit was oblate to spherical. By selfing and sibbing different offsprings of these two plants and considering the segregants, definite monohybrid ratios were obtained. This indicated that a pair of independent genes control habit of flowering and that monoecious habit of flowering is dominant over andromonoecious habit of flowering. No definite ratios indicative of an interaction between shape of fruit and habit of flowering could be established. Plants bearing defective reproductive organs had fruits which were intermediate in shape. It is our belief that more than two pairs of genes are responsible for the gradation in fruit shape and the interaction between habit of flowering and shape of fruit.Publication No. 4, Department of Agronomy, College of Agriculture, Pahlavi University, Shiraz, Iran.Department of AgronomyDepartment of Agronomy