番木瓜对不同施肥模式的响应及经济效益分析

为了探讨番木瓜高产高效栽培与合理施肥模式之间的平衡点,确保番木瓜高产优质,施肥模式经济高效。通过连续2年的田间小区定位试验,研究了5种不同施肥模式（专用肥,T1;专用肥+改良剂,T2;专用肥+精制有机肥,T3;精制有机肥,T4;生物有机肥,T5）对番木瓜营养生长、产量及品质的影响,开展了不同施肥模式的经济效益分析。结果表明：与T1处理对比,T2、T3处理均表现出促进番木瓜冠幅、株高生长增加的趋势。整个示范区番木瓜株产40.2~49.3 kg,平均单果重0.38~0.41 kg,单株收获商品果实105.8~120.4个。T3处理较T1处理增产18.6%,差异显著。糖度的方差分析结果显示,T1处理显著低于T4、T5处理,T4、T5处理均显著低于T2、T3处理。不同施肥模式鲜果肉维生素C含量与糖度的趋势一致。从经济效益来考察,T3处理获得的净产值最高（413819元/hm2）,产投比为T3≈T2>T5≈T1>T4处理。     

PEG介导番木瓜叶肉原生质体瞬时表达体系的建立

本研究对聚乙二醇(polyethylene glycol,PEG)的分子量、浓度及处理时间等三个影响番木瓜叶肉原生质体转化效率的主要因素进行了优化,同时利用绿色荧光蛋白(green fluorescent protein,GFP)表达体系进行了转化表达分析。结果表明:经40%PEG8000溶液处理10 min,可使GFP在原生质体中的平均转化率达到45.26%;沉默抑制载体p Green-Hcpro和GFP瞬时表达载体共转化番木瓜叶肉原生质体,可使GFP在原生质体中的平均转化率进一步提高到68.75%,相比单独转化瞬时表达载体p RNAi-GFP增长了51.90%。PEG介导番木瓜叶肉原生质体瞬时表达体系的建立为番木瓜功能基因组和基因功能研究奠定了基础,可为热带作物的研究提供又一模式作物,推动热带作物在分子及细胞生物学领域的发展。     

番木瓜生姜复合饮料配方及澄清工艺的研究

以番木瓜和生姜为主要原料．对番木瓜生姜复合饮料的配方及澄清工艺进行了研究。结果表明,番木瓜生姜复合饮料的优化配方为：番木瓜汁与姜汁的配比为3：2,白砂糖的添加量为5．0％,柠檬酸的用量为0．15％;采用0．15g·L^-1的硅藻土能明显提高番木瓜汁的澄清度,采用0．20g·L^-1的果胶酶能明显提高姜汁的澄清度。将两种清汁复合加工而成的番木瓜生姜复合饮料具有浓郁的番木瓜果香、淡淡的生姜芳香及良好的澄清度,透光率可达86．2％。     

番木瓜酸奶的加工工艺研究

番木瓜酸奶除具有普通酸奶的生物学价值外,还有番木瓜特殊的芳香,且果料的添加使酸乳制品更易消化吸收、更富色香味、更具吸引力。以优质奶粉与成熟的番木瓜为原料,以保加利亚乳杆菌和嗜热链球菌1∶1混合为发酵剂,在均质、杀菌、冷却后加入发酵剂进行液态发酵生产番木瓜酸奶。在相同的稳定剂条件下,以不同的番木瓜浆添加量、蔗糖用量、发酵时间、发酵剂的接种量进行发酵的正交试验,对产品进行感观评价,以此来确定最佳的工艺参数及配比,为番木瓜酸奶最佳生产工艺的研究提供依据。结果表明,采用保加利亚杆菌和嗜热链球菌(1∶1)混合菌为发酵菌种,取番木瓜浆与牛奶的体积比2∶3,蔗糖用量20 g,发酵时间4 h,发酵剂的接种量6 mL,加糖量为10%,稳定剂CMC 0.02%,发酵温度为42℃,以此工艺条件制备的番木瓜酸奶,具有独特的风味和较高的营养价值。     

Effect of wounding on cell wall hydrolase activity in tomato fruit

Changes in the activity of the cell wall hydrolases – polygalacturonase (EC 3.2.1.15), pectinesterase (EC 3.2.1.11) and β-galactosidase (EC 3.2.1.23) – have been investigated following wounding of tomato fruit pericarp tissue (Lycopersicon esculentum cv. Ailsa Craig). In ripening fruit wounding appears to arrest the further synthesis of polygalacturonase. β-Galactosidase synthesis may also have been arrested in ripening fruit. The level of pectinesterase declined over the first 24 h following harvest, and since this was apparent in both wounded and unwounded tissue may be related to a harvest, rather than a wounding effect. There was a recovery of activity in intact fruit by 48 h after harvest but this seems to be impaired in wounded tissue. In the case of pectinesterase, this observation was extended to examine the changes in isoform profile and it appeared that the decline of this enzyme may be associated with the reduction of one specific isoform — PE2. In contrast to ripening fruit, wounding of fruit at the fully ripe stage appears to have no significant effects on the activities of any of these three enzymes.     

Soil and plant nutrient management and fruit production of papaya (Carica papaya) in Keaau,Hawaii

Abstract

Variations in papaya yields and fruit quality between papaya growers in Keaau, Hawai’i are mainly caused by differences in nutrient management. The objectives of this study were to (1) identify soil chemical properties and plant mineral compositions and their correlations in commercial papaya orchards; (2) compare soil chemical properties and plant nutrient concentrations between papaya orchards with low, medium and high fruit yields; (3) compare soil chemical properties and plant nutrient composition between orchards with low, medium and high fruit quality; (4) determine the difference in soil chemical properties, plant nutrient composition, and papaya yield and quality between new and long-term papaya land. Between 2016 and 2018, soil and plant tissue samples were collected from 100 commercial papaya orchards. Soil pH, potassium (K), calcium (Ca), and magnesium (Mg) were below and phosphorus (P) was above the recommended range for papaya. Petiole P, K, Ca, and sulfur (S) concentrations were below the recommended range. Fields with low fruit yields and low fruit quality were deficient in P, K, Ca, and zinc (Zn). Long-term papaya land had significantly (p?<?0.05) lower soil pH, total carbon (C), K, Ca, Mg, and sodium (Na), and higher concentrations of soil P than new papaya land. Nitrogen (N), boron (B), zinc (Zn), and copper (Cu) was significantly higher and Ca was significantly lower in petioles from papaya crops grown on long-term papaya land compared to new papaya land.     

Fe‐deficiency tolerance in papaya (Carica papaya L.): Ph reduction and chlorosis recovery in response to stress

The phenomenon of Fe‐stress response mechanism was examined using papaya as a test fruit plant species. This plant behaved like the many Fe‐efficient crop cultivars, reduced the pH of the minus Fe nutrient medium, followed by recovery from chlorosis. The response mechanism was observed in both the 2 cultivars, CO‐1 and CO‐3. Evidence obtained with this plant supports the widespread occurrence of the mechanism in diverse crop species ‐ grain, vegetable and fruit crop plants too.     

Karlheinz richter zum 65. geburtstag

Studies were carried out on spatio-temporal variations of arbuscular mycorrhizal (AM) fungi associated with Carica papaya L. growing in two different geographic localities in Goa, India – Western Ghats and coastal area, differing in soil characteristics and plantation status. The study recorded considerable variation in root colonization, spore density and distribution of AM fungi in the selected sites. The mean total root colonization was at a maximum in the month of July, while spore density was highest in April. The study recorded a total 33 species of AM fungi. Western Ghats recorded a relatively higher diversity of AM fungi compared to coastal area. Species richness of AM fungi was at a maximum in April and coincided with maximum mean spore density. Edaphic as well as climatic factors influenced the AM fungal parameters. The study recorded the existence of seasonality in AM fungi.     

Genetic structure of highland papayas (<Emphasis Type="Italic">Vasconcellea pubescens</Emphasis> (Lenné et C. Koch) Badillo) cultivated along a geographic gradient in Chile as revealed by Inter Simple Sequence Repeats (ISSR)

In Chile Vasconcellea pubescens is cropped to produce canned fruit, juice, jam and processed sweets. Additionally this species produces latex with a high level of papain, an important and valuable proteolytic enzyme with industrial applications. In this investigation seven ISSR primers were used to study the level and organization of genetic diversity in 333 samples of V. pubescens. Out of the 114 bands recorded, 63 proved to be polymorphic (P = 55.3%). At the species level, the genetic diversity was rather low (h = 0.01 ± 6,80188E-05, Shannon’s Index I = 0.16 ± 0,000148). The major portion of the genetic diversity was found within groups (65%). The genetic differentiation between the different groups was significant, as the AMOVA analysis suggested (Φ_pt = 0.35). When analysing the Northern area alone, the differentiation increased to Φ_pt = 0.40. When only the Southern area was analysed, Φ_pt decreased to 0.18, indicating greater genetic similarity among the samples. The results generated from Structure and Bayesian Analysis of Population Structure distinguished 8 genetically different groups, five of them located in the north and three in the south. The results are discussed in the light of the growers’ practices.     

All hermaphrodite progeny are derived by self-pollinating the sunrise papaya mutant

Self‐pollination of a hermaphroditic cultivar normally gives a ratio of 2 : 1 hermaphrodite to female papayas with genotypes M₂m and mm, respectively. Much effort has been dedicated to marking the sexual types of papaya at the seedling stage to distinguish hermaphroditic from female papayas. A hermaphroditic papaya mutant (SR*) has been obtained, derived from the ‘Sunrise’ papaya cultivar mutant. Self‐pollination of the mutant resulted in all progenies being hermaphroditic. The genotype of the female was lethal, as a result of a lethal gene being linked to the mm female gene complex in this case. However, a 3 : 1 segregation ratio was obtained from the progeny of the hermaphroditic cultivar ‘Thailand’ crossed with SR*, indicating that all genotypes survived. Homozygous genotypes (M₂M₂) would be lethal according to Storey's model. Randomly selected F1 plants of the ‘Thailand’ SR* combination were self‐pollinated to obtain an F₂ generation. The F₂ segregation ratio suggested that the SR* mutant had a different form of the M₂ allele, now designated as M_@, which allowed the dominant M_@M₂ to survive in cross combinations. Genetic study has proved that SR* has the M_@ml genotype, a new mutant. It is capable of producing all hermaphroditic papaya progenies.