Papaya yellow leaf curl virus: A newly identified begomovirus infecting Carica papaya L. from the Indian Subcontinent

India is one of the world’s largest producers of papaya. Viruses, mainly begomoviruses and potyviruses, cause a significant loss in papaya production. The study described here has identified a new species of begomovirus and a new species of betasatellite infecting Carica papaya in India. The sequences of the begomovirus and betasatellite show 90.03% nucleotide sequence identity to an isolate of Radish leaf curl virus and 92.25% identity to an isolate of Tomato leaf curl betasatellite, respectively. Maximum likelihood phylogenetic tree of begomovirus sequence of isolate DP2 (KX353622) showed distant relationships with previously characterised begomoviruses. Recombination analysis proposed six recombination breakpoints in begomovirus genome with other geographical begomovirus isolates.     

Papaya pollen viability and storage

Papaya pollen viability, tube growth and storage were studied. Pollen germination on a drop of modified Brewbaker medium at 22–26°C closely reflected in vivo germination. Two vital stains gave pollen viability estimates that correlated closely with pollen germination percentage. The time from pollination to first ovule penetration was 25 h at 28°C, no in vitro pollen germination was observed at 5°C and at 40°C pollen tube growth was retarded. High relative humidity (70–80%) hastened the process compared with low relative humidity (30–40%).

Pollen could be stored successfully for 6 months when kept at − 18°C in a deep-freezer. Storage of pollen for the winter months, during which no or very little viable pollen is formed in the coastal area of Israel, seems a practical means to ensure adequate fruit set.     

温室番木瓜栽培技术

番木瓜,也称木瓜、万寿果、乳瓜,是多年生高大草本植物,原产美洲热带,属喜温作物.在我国,露地栽培区域主要分布在广东、海南、广西、云南、福建及台湾等省.番木瓜果实富含维生素A和维生素C,还含有抗癌作用的活性木瓜碱和助消化、治疗胃病的木瓜蛋白酶,兼有营养和药用价值.清甜适口.番木瓜在我国北方温室栽培,可常年采收到成熟的果实,作为水果食用;未成熟的青果可作蔬菜食用.……     

Effect of Ethephon Latex Stimulant on Papaya (Carica Papaya L.)

The effect of ethephon latex stimulant mixed in coconut oil and applied to immature green fruits of Co.2 papaya was studied in respect of papain yield and quality of fruits. Papain yield could be increased four-fold over the control by the application of ethephon latex stimulant at 34 mM in coconut oil. Ethephon also improved the quality of papain, and also the quality of fruits by increasing total sugars and reducing sugars and decreasing acidity.     

Optimum Level of Nitrogen and Phosphorus to Achieve Better Papaya (Carica papaya var. Solo) Seedlings Growth and Mycorrhizal Colonization

An experiment under greenhouse conditions was carried out to evaluate the best level of nitrogen (N) and phosphorus (P), which promote the growth of papaya (Carica papaya L. var. Solo) seedlings without affecting the arbuscular mycorrhizal fungi (AMF) activity. Seedlings of papaya were transplanted to pots inoculated or not with Gigaspora margarita spores at four levels of N (0, 50, 100, and 200 ppm) and P (0, 25, 50, and 100 ppm). P was amended at the same time of pot filling up with substrate but N was applied weekly. The experiment was harvested after 100 days and plant dry weight together with AMF colonization was measured. The major response on the plant dry weight and height was from the fertilizers (N and P) where it proportionally increased. For the dry weight, at low amounts of nutrients the effects of AMF were greater, but as much as the fertilizer level in soil increased this response decreased. The colonization decreased as the nutrient levels increased, especially the P. The best combination of N and P for plant growth and AMF colonization could be at 50 and 25 ppm, equivalent to 5 and 2.5 kg/10a, respectively.     

Factors Affecting the Storage Behaviour of Papaya Fruit

Fruits of the papaya cultivar Solo 63/2 were damaged when stored at or below 45 °F (7 °C). Wrapping the fruit in polyethylene bags reduced weight loss during storage but increased the development of saprophytic fungi. Perforated polyethylene bags similarly reduced weight loss but did not increase fungal development.

Careful harvesting significantly reduced fungal infection, thus giving the fruits better flavour and longer storage life. The optimum stage of maturity for satisfactory storage and subsequent ripening was when the yellow colour was just beginning to develop in the funicles. Fruits from hermaphrodite trees were superior in flavour to those from female trees but behaved similarly during storage.     

用RT-PCR检测PRSV在番木瓜体内的运转

以抗病突变体岭抗1号与穗中红番木瓜为试材,人工接种PRSV-Ys株系,应用RT-PCR技术检测PRSV在体内的运转.结果表明,感病品种穗中红接种后24 h,即可在接种叶的未接种部位检出病毒,第10 d在接种植株的各部位均可检出病毒;而在岭抗1号植株上,接种后直至第10 d,仍未能在其他部位检测出病毒,表明岭抗1号具有阻碍病毒运转的能力.     

海南番木瓜丰产栽培措施总结

近年来,随着人们对番木瓜营养和保健价值认识的逐步深入,番木瓜越来越受到人们的青睐,市场需求不断增大。海南省是我国番木瓜的主要产地之一,但该地区雨量不均、台风常袭、病虫害发生严重,番木瓜的生产受到很大影响。因此,海南番木瓜要获得高产、稳产就应该把握科学的栽培技术。     

番木瓜玻璃化组培苗逆向生长培养

在植物组织培养中常发生玻璃化现象,大多将玻璃化苗剔除弃之,这使工厂化大规模组培苗生产增加了较大成本和风险.利用番木瓜营养液培养其玻璃化组培苗能有效地控制玻璃化苗的发生,使其逆向转化.比较了两种营养液培养基逆向转化玻璃化组培苗的效果.     

番木瓜体胚间接发生方式的研究

 为了建立小果型番木瓜(Carica papaya L.)高效外源基因遗传转化体系，以小果型番木瓜'美中红'的幼胚(授粉受精后90~120 d)为材料,通过组织切片和电镜观察了体胚发生方式。结果表明，培养8~12 d，愈伤组织首先发生于幼胚的胚根端；培养26 d，整个幼胚的胚轴愈伤化，愈伤组织分为粘性透明和干性两大类，组织切片分为明显的两层，外层疏松易脱落，内层结构紧密；培养38 d，淡黄色的体胚前体发生于幼胚的胚芽端。番木瓜体胚的形态各异，大多数是形态正常的体胚，少数体胚的形态发生变异。     

番木瓜抗PRSV突变的抗病性鉴定

通过接种PRSV Ys、Vb和Sm3个株系及田间诱发鉴定,研究了抗PRSV突变岭抗1号（聪1）的抗病稳定性。结果表明,LK-1表现出高抗PRSV-Ys和PRSV-Vb2个株系的能力,对PRSV．Sm株系则无明显抗病能力,抗病性不因自交繁殖而丧失,种植到田间的接种苗成株期的田间抗性表现与苗期表现基本一致,表明LK-1的抗病性能具较高的稳定性。     

大田番木瓜外植体消毒灭菌方法探讨

以大田番木瓜侧芽为材料,研究番木瓜外植体预处理方法和消毒程序。结果表明,使用1%消佳浄溶液处理5分钟的效果最好。大田番木瓜外植体材料的消毒程序为:1%消佳浄溶液预处理5分钟-75%酒精浸泡30-秒2 000 mg/L升汞溶液浸泡8分钟或1 300 mg/L ClO2浸泡6分钟。     

番木瓜体胚发生及植株再生研究

研究了外植体类型及培养基的不同激素配比等因素对番木瓜愈伤组织诱导和体胚发生的影响。结果表明,番木瓜的子叶和幼胚两种不同的外植体均能诱导愈伤组织、体胚发生和实现植株再生,但在愈伤组织诱导上存在差异,在MS+2,4-D1.00mg/L+BA0.30mg/L+NAA0.05mg/L培养基上诱导的愈伤组织较好。添加一定浓度的硫酸腺嘌呤(ADS)、水解酪蛋白(CH)可以促进番木瓜体胚发生,在生根培养基上生根后,可移栽成活。     

番木瓜茎尖超低温保存过程中的细胞超微结构

 采用透射电子显微镜对番木瓜(Carica papaya L. ) 茎尖超低温保存过程中细胞超微结构变化进行观察。结果表明: 细胞在经过预培养、60% PVS₂ 预处理和PVS₂ 脱水处理, 细胞质壁分离程度逐渐加重,细胞的抗冻力增加。细胞严重伤害主要发生在液氮保存的降温及解冻的过程中, 一部分细胞的细胞壁、细胞膜以及细胞核膜均有不可逆的损伤, 可能是导致部分细胞致死的原因之一。也有部分细胞结构完整, 虽然细胞结构发生了变化, 但是程度不深, 是可逆的伤害, 在恢复培养3 d时可自动修复, 然后再生出植株。     

番木瓜ERF家族与果实成熟相关成员的分析

通过比较分析番木瓜ERF家族成员的系统进化关系、基本理化性质、保守基序、启动子顺式元件,结合分析番木瓜在乙烯利和乙烯抑制剂1–甲基环丙烯(1-MCP)处理下以及不同成熟期果肉的RNA-seq数据,筛选出22个ERF家族成员进行表达差异分析,最终比较得出两个处理数据中显著差异表达基因有18个,推测这些基因可能在番木瓜果实成熟过程中起重要作用。     

曹州木瓜的观赏特性与园林应用

曹州木瓜具有很高的园林应用价值,现就树形、树干、叶、花、果等方面介绍曹州木瓜的观赏特性,并探讨其在园林中的应用。     

CPPU对番木瓜干旱胁迫的保护作用

干旱胁迫下,番木瓜叶片水势、可溶性蛋白质、叶绿素含量和SOD活性明显下降,而电导率、POD活性、MDA和H2O2含量则显著上升。分别用10、30、50mg/L的CPPU预处理有效地降低了干旱条件下番木瓜叶片细胞的MDA、电导率和H2O2含量的增加程度,并能减缓叶片叶绿素总含量和可溶性蛋白质含量的降低。试验表明CPPU是通过减轻干旱对番木瓜引起的自由基伤害来提高番木瓜的抗旱能力,其中以30mg/L浓度的CPPU处理效果最好。     

番木瓜茎尖的玻璃化法超低温保存及其植株再生

 研究了番木瓜( Carica papaya L. ) 茎尖玻璃化法超低温保存的一些影响因素。结果表明: 无菌试管苗在MS + BA 0.5 mg/L + NAA 0.1 mg/L + GA₃ 1.0 mg/L 的培养基上生长较好。番木瓜茎尖超低温保存较佳体系是: 3～5 cm的茎尖在含有5 %二甲基亚砜(DMSO) 培养基上预培养3 d , 解剖镜下剥取含1～2 个叶原基的茎尖(1.5～2.5 mm长) , 先在室温下于60 %的玻璃化溶液(PVS2) 中装载40～50 min , 再用PVS2于0 ℃下处理30 min , 换1 次PVS2 溶液后迅速投入液氮。保存24 h 后, 在40 ℃水浴中化冻, 用1.2 mol/L 的蔗糖培养液洗涤两次, 转入继代培养基上再培养, 成活率和再生率分别达53.7 %和52.6 %。再生植株生根后可移栽成活。     

模拟酸雨对番木瓜叶片细胞膜透性和膜脂脂肪酸组分的影响

 研究了不同pH 值(4.5 、3.5 、3.0 、2.5) 的模拟酸雨对番木瓜叶片细胞膜透性和膜脂脂肪酸组分的影响。结果表明, 酸雨处理导致细胞膜透性、MDA 含量、脂氧合酶(LOX) 活性及K⁺ 、Ca²⁺ 、Mg²⁺ 渗出量显著上升, 膜脂肪酸组分中饱和脂肪酸组分增加, 不饱和脂肪酸组分及不饱和指数( IUFA)下降。用差异显著性检验结果为判量标准初步评价模拟酸雨对番木瓜叶片生理指标的影响阈值为pH 3.0 。     

番木瓜开花相关基因CpFT1及启动子的克隆与表达分析

以番木瓜（Carica papaya L.）花为材料,利用番木瓜基因组序列设计番木瓜CpFT1和启动子扩增引物,通过PCR获得了该基因长度为525 bp的基因组DNA序列和1 500 bp的上游调控序列。通过生物信息学分析,发现CpFT1编码174个氨基酸。经序列对比及进化分析发现,番木瓜FT基因与山毛榉FT基因同源性最高。亚细胞定位显示CpFT1蛋白定位于细胞核。进一步分析CpFT1的启动子序列,脱落酸、赤霉素、水杨酸等激素调控相关的元件位于CpFT1上游1 500 bp的序列上。利用实时荧光定量PCR检测了CpFT1在不同性别花器官、花不同发育阶段以及不同激素处理下花中的表达差异,结果表明CpFT1的表达可能受到脱落酸、水杨酸等激素的调控。