Contents of Sugars, Fruit Acids, Amino Acids and Phenolic Compounds of Apple Fruits i n Relation to their Susceptibility to Botryosphaeria ribis

Five apple cultivars showing different levels of susceptibility to Botryosphaeria ribis were used to study the relationship between susceptibility and contents of sugars, fruit acids, amino acids and phenolic compounds in the fruits at various stages of maturity. Immature fruits of all the cultivars tested were completely resistant until 10 July. The fungus grew better on the yellow-coloured cultivars than the red-coloured cultivars. The low amount of reducing sugars and also the high levels of fruit acids, amino acids and total phenols were found in immature apple fruits, irrespective of cultivar. No consistent differences between the cultivars were recognized with regard to the contents of soluble sugars, fruit acids and phenols in fruit flesh during the maturity of fruits. However, only the levels of total soluble amino acids in fruit flesh and of total phenols in fruit peel at late stage of maturity consistently varied between the cultivars. The dark red-coloured, resistant cultivars Miller spur and Starkrimson showed higher contents of amino acids and phenols in fruit tissues than did the yellow-coloured, susceptible cultivars.     

Xyloglucan endotransglycosylase activity during fruit development and ripening of apple and kiwifruit

Xyloglucan endotransglycosylase (XET) activity was measured in apple (Malus domestica Borkh. cv. Braeburn) pericarp and kiwifruit (Actinidia deliciosa [A. Chev.] C. F. Liang et A. R. Ferguson var. deliciosa cv. Hayward) outer pericarp and core tissues in order to establish whether a correlation exists between the activity of the enzyme and different stages of fruit development Whereas the growth rate of kiwifruit paralleled changes in XET activity throughout fruit growth, that of apple did not. Both fruits showed the highest XET activity, on a fresh weight basis, in the first two weeks after anthesis when cell division was at its highest. XET activity then decreased sharply, but as the fruit increased in size (4–8 weeks after anthesis) there was a concomitant increase in XET activity in both fruits. In the latter stage of fruit development (16–26 weeks after anthesis) XET activity increased to peak at harvest in apple fruit. During this time there was relatively little increase in fruit size and presumably therefore minimal cell expansion. XET activity then declined as fruit softened after harvest. In core tissue from kiwifruit, XET activity increased throughout the later stages of fruit growth to harvest maturity in a similar manner to apple, but continued to increase after harvest until fruit were ripe. In contrast, XET activity in the outer pericarp of kiwifruit did not increase until ripening after harvest. In apple tissue up to 30% of the XET activity was cell wall bound and could not be solubilised, even in buffer containing 2 M NaCl. The results implicate XET in cell wall assembly during cell division and expansion early in apple and kiwifruit growth. However, the disparity between apple and kiwifruit with respect to XET activity late in fruit development and ripening and the different affinities of the enzyme for the cell wall in each fruit, suggest that XET has several roles in plant development, not all of which are related to cell wall loosening during periods of accelerated growth.     

Trade-Offs of Flowering and Maturity Synchronisation for Pineapple Quality

In the pineapple sector of Benin, poor fruit quality prevents pineapple producers to enter the European market. We investigated effects of common cultural practices, flowering and maturity synchronisation, (1) to quantify the trade-offs of flowering and maturity synchronisation for pineapple quality and the proportion of fruits exportable to European markets, and (2) to determine the effect of harvesting practice on quality attributes. Four on-farm experiments were conducted during three years using cultivars Sugarloaf and Smooth Cayenne. A split-split plot design was used in each experiment, with flowering induction practice as main factor (artificial or natural flowering induction), maturity induction practice as split factor (artificial or natural maturity induction) and harvesting practice as the split-split factor (farmers’ harvest practice or individual fruit harvesting at optimum maturity). Artificial flowering induction gave fruits with lower infructescence weight, higher ratio crown: infructescence length, and a lower proportion of fruits exportable to European markets than natural flowering induction. The costs of the improvements by natural flowering induction were huge: the longer durations from planting to flowering induction and harvesting, the higher number of harvestings of the fruits increasing the labour cost and the lower proportion of plants producing fruits compared with crops from artificially flowering-induced plants. Artificial maturity induction decreased the total soluble solids concentration in the fruits compared with natural maturity induction thus decreasing the proportion of fruits exportable to European markets, at a benefit of only a slightly shorter time from flowering induction to harvesting. Harvesting individual fruits at optimum maturity gave fruits with higher total soluble solids in naturally maturity induced fruits compared with the farmers’ harvest practice. Given the huge costs of natural flowering induction, options to use artificial flowering induction effectively for obtaining high fruit quality are discussed.     

Effect of postharvest salicylic acid treatment on fungal decay and some postharvest quality factors of kiwi fruit

The effect of salicylic acid (SA) treatment at different concentrations on fungal decay and some quality factors of kiwi fruit (Actinidia deliciosa var. Hayward) in postharvest conditions were studied. Results experiment showed that SA at all applied concentrations inhibited grey mould growth. The SA application significantly decreased weight loss percentage and increased life storage fruits. Also, SA positively affected on postharvest quality factors including total soluble solids (TSS), titratable acidity (TA), antioxidant, ascorbic acid and pH value. It was observed that treated fruits with SA at concentration 5?mM had the highest TSS, TA, ascorbic acid and antioxidant content and it had the lowest decay and acidity. Thus, these results showed that SA has strong impact on postharvest decay and fruit quality of kiwi fruit.     

Effect of a Protein Polygalacturonidase Inhibitor from Apple Fruit Tissue on the Enzyme Released by Fungal Pathogens

A protein polygalacturonidase inhibitor isolated from fruit of the apple cultivars Antonovka and Mantuanskoe differently affects the polygalacturonidases of different phytopathogenic fungi. Three groups of fungi were recognized according to the sensitivity of their polygalacturonidases to the inhibitory effect. Storage of apples after harvesting is accompanied by changes in the inhibitor activity, and the time pattern of these changes depends on the cultivar. An increase in the inhibitor activity occurs concurrently with the elevation in ethylene release characteristic of the stage of elevated respiration (a climacteric increase). The data suggest that a decrease in the apple fruit resistance to microbes at the end of the storage period is related, along with other reasons, to a change in the activity of the protein polygalacturonidase inhibitor.     

Superoxide dismutase and catalase activities in apple fruit during ripening and post‐harvest and with special reference to ethylene

Oxidative stress is involved in many biological systems, among which are fruit ripening and senescence. Free radicals play an important role in senescence and ageing processes. Plants have evolved antioxidative strategies in which superoxide dismutase (SOD, EC 1.15.1.1) and catalase (CAT, EC 1.11.1.6) are the most efficient antioxidant enzymes, influencing patterns of fruit ripening. Variations in total SOD and CAT activities were determined at regular intervals during ripening and senescence in on‐tree and cold‐stored apple fruits of the cultivars Fuji and Golden Delicious. In all fruits, internal ethylene concentration was also measured. The results suggest that the onset of ripening, signalled by ethylene burst, is closely related to SOD and CAT activities. In on‐tree fruits the climacteric peak in ethylene was associated with the peaks of SOD and CAT activity in both cultivars. Quite different results were obtained in cold‐stored fruits: Ethylene concentration increased in both cultivars during the storage. CAT activity doubled in both cultivars. SOD activity decreased in Golden Delicious and peaked in Fuji.     

Change in chemical constituents and free radical-scavenging activity during Pear (Pyrus pyrifolia) cultivar fruit development

Changes in chemical constituent contents and DPPH radical-scavenging activity in fruits of pear (Pyrus pyrifolia) cultivars during the development were investigated. The fruits of seven cultivars (cv. Niitaka, Chuhwangbae, Wonhwang, Hwangkeumbae, Hwasan, Manpungbae, and Imamuraaki) were collected at 15-day intervals after day 20 of florescence. Vitamins (ascorbic acid and α-tocopherol), arbutin, chlorogenic acid, malaxinic acid, total caffeic acid, total flavonoids, and total phenolics were the highest in immature pear fruit on day 20 after florescence among samples at different growth stages. All of these compounds decreased gradually in the fruit during the development. Immature pear fruit on day 35 or 50 after florescence exhibited higher free radical-scavenging activity than that at other times, although activities were slightly different among cultivars. The chemical constituent contents and free radical-scavenging activity were largely different among immature fruits of the pear cultivars, but small differences were observed when they matured.     

逆境条件下小麦种子活力与种子萌发相关酶活性及其基因表达的关系

分析不同基因型小麦品种逆境萌发过程中种子萌发相关酶活性及基因表达差异,明确在逆境条件下,种子活力与种子萌发相关酶活性及基因表达量的关系.通过标准发芽试验和逆境(冷浸、人工老化、干旱胁迫)发芽试验,测定4个小麦品种种子活力、萌发过程中可溶性总糖和可溶性蛋白含量、α-淀粉酶活性、半胱氨酸蛋白酶活性及相关基因表达量.结果表明:干旱、人工老化和冷浸胁迫3种逆境对种子活力都有一定影响.不同萌发条件下,可溶性总糖含量呈现先小幅度升高后小幅度降低再迅速升高的趋势;而可溶性蛋白含量随着萌发时间的延长呈现逐渐下降的趋势.α-淀粉酶活性整体呈现逐渐升高的趋势,但在冷浸胁迫处理后,豫农949和轮选061的α-淀粉酶活性在萌发60 h后出现下降.半胱氨酸蛋白酶活性整体呈先降低后升高的趋势,但在干旱胁迫条件下,豫农949、豫麦49-198和轮选061的半胱氨酸蛋白酶活性呈现先升高后降低再升高的趋势.不同逆境萌发条件下,α-AMY(α-淀粉酶基因)表达量整体呈先上升后下降的趋势.冷浸胁迫处理后,轮选061的α-AMY表达量高于对照,在其他逆境萌发条件下,4个品种的α-AMY表达量均低于对照;人工老化处理后,长4738的CP(半胱氨酸蛋白酶基因)表达量与对照差异不显著,在其他逆境萌发条件下,4个品种的CP表达量均高于对照.种子萌发期间,不同萌发条件下α-淀粉酶和半胱氨酸蛋白酶活性与其基因表达并没有直接关系,α-淀粉酶活性与可溶性总糖含量达到显著正相关,半胱氨酸蛋白酶活性与可溶性蛋白含量的相关性不显著.在标准发芽条件下,α-淀粉酶活性与活力指数呈显著正相关,而在逆境萌发过程中,其相关性不显著.冷浸胁迫处理后,半胱氨酸蛋白酶活性与活力指数呈显著正相关,但在标准发芽、干旱胁迫、人工老化处理后,其相关性不显著.     

温州蜜柑果实发育过程中矿质营养元素含量的动态变化

本文分析了温州蜜柑丰产园不同发育阶段的果实氮、磷、钾、钙、镁、铁、锰、锌、铜、硼的含量。矿质元素在果实中的动态变化规律与叶片中的变化规律显然不同。一是含量比叶片低;二是浓度的最高峰期出现比叶片早。果实发育前中期元素含量变化较复杂,9月以后趋向稳定。对可否以9月至10月上旬作为采果样时期以进行营养诊断作了讨论。     

Role of the Polygalacturonidase Inhibitor Protein in the Ripening of Apples and Their Resistance to Monilia fructigena, a Causative Agent of Fruit Rot

We investigated the dynamics of the activity of the polygalacturonidase inhibitor protein (PGIP) in apple fruits of six cultivars differing in ripening time and correlated it with the degree of damage by the causative agent of fruit rot, Monilia fructigena. The apple cultivars studied differed significantly in PGIP activity and degree of damage by Monilia fructigena. The rate of dissemination of the fungus over fruit tissues was inversely related to PGIP activity. The resistance of apples to M. fructigena increased with ripening. The simultaneous increase in PGIP activity suggests its important role in the reduction of apple damage by fruit rot.     

Blossom-end rot in relation to growth rate and calcium content in fruits of sweet pepper (Capsicum annuum L.)

The relative importance of growth rate and calcium concentration in sweet pepper fruits (Capsicum annuum L.) for the induction of blossom-end rot (BER) was investigated in (1) four pollination treatments in one cultivar, (2) four cultivars with the same fruit load and (3) three fruit load treatments in four cultivars. For fruits with the same pollination treatment those eventually developing BER had a higher initial fruit growth rate than those not developing BER. Within the same experiment both the growth rate of the young fruit and BER increased with the number of seeds. The Ca concentration of the pericarp in mature fruits was negatively related to both fruit size and BER incidence. Differences in levels of BER between different pollination experiments could not be explained solely by differences in growth rate of the young fruit, but related to different Ca concentrations in the mature fruits. In the spring, but not in the summer, cultivars more susceptible to BER had a larger final size but lower Ca concentration in the young fruit than the resistant ones. By lowering the fruit load in the summer both the final fruit size and the BER incidence increased, but the Ca concentrations of both proximal and distal pericarp in the young fruit of all cultivars were not consistently affected. Despite a correlation between growth rate and low Ca concentration in the fruit, the incidence of BER may only be predicted from separate effects of fruit growth and of Ca concentration of fruit. The data indicated that at a higher growth rate a higher Ca concentration is required to prevent the induction of BER. The usefulness of the total Ca concentration of the fruit for determining the critical Ca concentration in the induction of BER is discussed.Key words: Capiscum annuum L., sweet pepper, blossom-end rot, calcium, growth rate, pollination, fruit load.      

采前二氧化氯处理对‘海沃德’猕猴桃的防腐保鲜效果

研究了采前二氧化氯（ClO2）处理对采后‘海沃德’猕猴桃果实在冷藏条件下的防腐保鲜效果。分别用浓度（有效成分）为0、20、40、60、80mg·L-1的ClO2溶液,在采收前对果实进行喷布处理,在采收后冷藏过程中定期测定相关生理指标,并在贮藏末期（120d）观察统计其腐烂指数。结果表明,浓度60mg·L-1的ClO2采前处理可有效清除猕猴桃果实表面菌落,并能显著延缓冷藏期间果实硬度的下降、抑制可溶性固型物的上升、降低猕猴桃呼吸速率、乙烯释放速率、失重和腐烂指数,提高过氧化物酶（POD）和苯丙氨酸解氨酶（PAL）的活性。通过比较,确定采前ClO2处理的适宜浓度为60mg·L-1。该浓度的ClO2处理对‘海沃德’猕猴桃具有明显的防腐保鲜效果,可有效延长贮藏期。     

谷氨酸和TDZ对荔枝果皮着色及果实品质的影响

为提前或延迟果实的成熟,改善果实品质,以荔枝(Litchi chinensis Sonn.)早熟品种‘三月红’和‘水东’为试验材料,在盛花后50 d用谷氨酸(Glu)和TDZ(Thidiazuron)进行处理,研究Glu和TDZ对果皮着色和果实品质的影响。结果表明,Glu能促进果皮转红,500~1500 mg L-1范围内随浓度增加果皮红色面积加大,果皮的花青苷含量增加。1500 mg L-1Glu处理的‘三月红’‘、水东’果皮花青苷含量分别达到8.62 U g-1、11.53 U g-1,分别比对照高出1.33、1.25倍。同时,Glu处理能促进‘三月红’总糖的积累,但对两品种果实大小和质量的影响不大。TDZ显著迟滞果实着色,果实转红延后,果皮花青苷含量降低。5.0 mg L-1TDZ处理的‘三月红’‘、水东’果皮花青苷仅为1.23和3.4 U g-1,显著低于对照。TDZ处理两品种果实的可溶性固形物、总糖含量均下降,但果实大小和质量均增加。因此,Glu能促进荔枝果实转色成熟,TDZ则抑制果实转色。     

硬肉桃果实成熟前后钙含量和钙ATP酶活性的变化及其与果实硬度的关系

以硬肉桃新品种‘双久红’果实为试材,以常规优良品种‘川中岛白桃’为对照,分别研究了成熟前20d和成熟后20d内两品种果实中钙含量和Ca^2＋-ATP酶活性变化以及它们与果肉硬度关系的结果表明：‘双久红’果实的总钙和Ca^2＋含量从成熟前15d开始极显著高于同期‘川中岛白桃’的,两者与果实硬度变化呈极显著相关（P〈0．01）,随着果实的成熟两者均呈下降趋势,Ca^2＋-ATP酶的调控能力也逐渐减弱,但‘双久红’果实中的Ca^2＋-ATP酶活性比‘川中岛白桃’高一些。     

Diet and Dietary Preferences of the Southern Cassowary (Casuarius casuarius) in North Queensland, Australia

We investigated the diet of the southern cassowary (Casuarius casuarius) by identifying the seeds and fruits in fecal droppings encountered on a set of transects over 2 yr in upland rain forest in the wet tropics of North Queensland. A total of 198 droppings containing 56 plant species were found. We surveyed fleshy fruit availability over the subsequent 68 mo on transects in the same area to ascertain fruiting patterns in the study area. The number of droppings found each month did not correspond to the pattern of available fruit biomass. There was no relationship between the fruit traits of moisture content, flesh to seed mass ratio, color, or crop size to contribution of a species to the diet. During the lean fruiting season (May–July) cassowaries relied more on species that fruited continuously throughout the year as they were significantly over‐represented in droppings, while annual fruiting species were under‐represented. During months of high fruit availability (October–December), continuously fruiting species were still over‐represented in the diet but became less important while annual and biennial species became more important. Significantly more species with large fruit and large seeds appeared in the diet than expected and we confirm that the cassowary contributes to the continued dispersal of these species over long distances and in large quantities.     

Localization and dynamic change of saikosaponin in root of Bupleurum chinense

Anatomical,histochemlcal and phytochemical methods were used to investigate the structure,the localization and content changes of total saikosaponin and saikosaponin-a of the roots of Bupleurum chinense DC.at different developmental stages.Results showed that saikosaponin was mainly distributed in pericycle and primary phloem in the young root;but In the mature root,it was mainly distributed in vascular camblum and secondary phloem.During the whole growth period from the pre-blossom,blossom,fruit,and fruit mature periods until the pre-withering period,it was in the fruit mature period that both the total saikosaponin content and the saikosaponin-a content reached the highest level.So the last 20 d of October was considered as the right collecting season for the drug of B.chinense.In addition,the quality of 1-year-old drug was better than that of 2-year-old drug due to its higher saikosaponin content.On the other hand,judging from the external characteristics of the drug,the one with an acerose taproot and more lateral roots was of better quality.The results offered theoretical bases for selecting medicinal material of high quality and determining the most appropriate harvesting stage and part of B.chinense.     

Changes in the Alkaloid Content of Developing Fruits of Tomato (Lycopersicon esculentum Mill.): I. ANALYSES OF CULTIVARS AND MUTANTS WITH DIFFERENT RIPENING CHARACTERISTICS

Normal ripening red-, orange- and yellow-fruited cultivars oftomato showed similar patterns of fruit growth and tomatineaccumulation to those of non-ripening mutants. In all fruits,the tomatine concentration declined continuously from an earlystage although the absolute amount per fruit showed a biphasicpattern of accumulation and decline. The turning point' occurredat an earlier developmental stage in normal fruits than in mutants.Normal fruits also had a lower initial and higher final tomatinecontent than mutants on a per fruit basis although, on a unitweight basis, their initial concentration was higher and finalconcentration lower. Small, prematurely-ripened red fruits hadalkaloid levels intermediate between large, unripe, green fruitsand large, ripe, red fruits. It is concluded that growth andripening processes may both contribute to the decline in fruittomatine. Key words: Tomato, Fruit ripening, Tomatine     

Neoculin, a taste-modifying sweet protein, accumulates in ripening fruits of cultivated Curculigo latifolia

Neoculin is a sweet protein with a taste-modifying activity of converting sourness to sweetness. It occurs in the fruits of Curculigo latifolia, a wild plant found in tropical Asia. We successfully cultivated the plant and evaluated the production of neoculin. The neoculin content of the fruit was high for 10 weeks after flowering, following which the yield decreased gradually. The optimal period for harvesting the fruits with sensory activity coincided with this 10-week peak period during which the amount of neoculin was 1-3mg in the whole fruit and 1.3mg/g of pulp. Immunohistochemical staining showed that neoculin occurred in the whole fruit, especially at the basal portion. Although it is known that neoculin comprises an acidic subunit (NAS) with an N-glycosylated moiety and a basic subunit (NBS), protein gel blot analysis revealed the presence of a non-glycosylated NAS species. This suggests the presence of multiple NAS-NBS heterodimers in our cultivar.     

Partitioning of (13)C-photosynthate from spur leaves during fruit growth of three Japanese pear (Pyrus pyrifolia) cultivars differing in maturation date

BACKGROUND AND AIMS: In fruit crops, fruit size at harvest is an important aspect of quality. With Japanese pears (Pyrus pyrifolia), later maturing cultivars usually have larger fruits than earlier maturing cultivars. It is considered that the supply of photosynthate during fruit development is a critical determinant of size. To assess the interaction of assimilate supply and early/late maturity of cultivars and its effect on final fruit size, the pattern of carbon assimilate partitioning from spur leaves (source) to fruit and other organs (sinks) during fruit growth was investigated using three genotypes differing in maturation date. METHODS: Partitioning of photosynthate from spur leaves during fruit growth was investigated by exposure of spurs to (13)CO(2) and measurement of the change in (13)C abundance in dry matter with time. Leaf number and leaf area per spur, fresh fruit weight, cell number and cell size of the mesocarp were measured and used to model the development of the spur leaf and fruit. KEY RESULTS: Compared with the earlier-maturing cultivars 'Shinsui' and 'Kousui', the larger-fruited, later-maturing cultivar 'Shinsetsu' had a greater total leaf area per spur, greater source strength (source weight x source specific activity), with more (13)C assimilated per spur and allocated to fruit, smaller loss of (13)C in respiration and export over the season, and longer duration of cell division and enlargement. Histology shows that cultivar differences in final fruit size were mainly attributable to the number of cells in the mesocarp. CONCLUSIONS: Assimilate availability during the period of cell division was crucial for early fruit growth and closely correlated with final fruit size. Early fruit growth of the earlier-maturing cultivars, but not the later-maturing ones, was severely restrained by assimilate supply rather than by sink limitation.