对羟基苯甲酸对豇豆枯萎病菌的抑制作用

研究了不同浓度的对羟基苯甲酸(p-HB)对豇豆枯萎病菌孢子萌发、菌丝生长及挑战接种后对幼苗发病率的影响。结果表明：低浓度p-HB对豇豆枯萎病菌菌丝生长抑制作用不明显,而中、高浓度（5.0、10.0 mmol·L^-1）p-HB对菌丝生长的抑制作用达到极显著水平;在1.0～10.0mmol·L^-1范围内,p-HB 随着浓度的升高对豇豆枯萎病菌孢子萌发的抑制作用越大;1.0～10.0 mmol·L^-1的p-HB均能降低幼苗的发病率,尤其是浓度为10.0 mmol·L^-1时,能显著降低幼苗的发病率。     

番木瓜种子果实内萌发的观察

从马来10号番木瓜Carica papayacv.Malai 10两年生植株采集3个成熟果实,放置1天后,剖开发现果实内均有大量种子萌发;平均含种子590粒,其中127粒已萌发,萌发率达21.6%;发芽种子根长0.2～1.8 cm,平均根长0.6 cm。说明种子在果实采摘前已萌发。     

番木瓜种子形成与结构的显微研究

首次报道了番木瓜种子的形成与结构,其胚珠倒生,长珠柄,双层珠被,不形成珠孔,合点端存在承珠盘.种子种皮由外至内包括3个部分,即透明的网膜状假种皮、皱褶致密的外种皮和黏稠的内种皮,其中内外种皮的最内侧各有一层褐色和透明状的厚壁细胞,黏稠的内种皮将这两层厚壁细胞黏连为一整体,最后形成坚硬的壳状物.种皮内包含有正常发育的子叶形胚与细胞型胚乳.     

对羟基苯甲酸胁迫对不同草莓品种光合作用及叶绿素荧光特性的影响

以对连作障碍具有不同抗性的草莓品种‘土特拉’、‘丰香’和‘全明星’为试材,采用温室盆栽试验研究了50、100和200 mg ? kg-1对羟基苯甲酸胁迫对草莓光合色素含量、光合作用气体交换参数和叶绿素荧光动力学特征的影响。结果表明：对羟基苯甲酸胁迫降低了3个品种草莓叶片叶绿素a、叶绿素b和类胡萝卜素的含量,且‘全明星’降幅最大。除‘丰香’的净光合速率和蒸腾速率在低浓度对羟基苯甲酸胁迫下有所提高外,‘土特拉’和‘全明星’的净光合速率、气孔导度和蒸腾速率均因对羟基苯甲酸胁迫而降低,且浓度越高降幅越大。100和200 mg ? kg-1对羟基苯甲酸胁迫均显著提高了草莓初始荧光Fo和非光化学猝灭系数qN;最高浓度胁迫下,‘全明星’、‘丰香’和‘土特拉’Fo分别比对照提高了15.1%、21.5%和9.3%,qN分别提高了131.3%、190.5%和26.6%。3个品种草莓最大荧光、PSⅡ反应中心潜在活性、PSⅡ最大光化学效率、PSⅡ有效光能转化效率和PSⅡ光合电子传递量子效率均随对羟基苯甲酸胁迫浓度的升高呈先升后降的趋势;各草莓品种叶绿素荧光参数综合优势表现为‘土特拉’>‘丰香’>‘全明星’。除50 mg ? kg-1胁迫没有明显影响‘丰香’和‘土特拉’干物质积累外,其他处理均显著降低了各品种地上部和地下部干质量及根冠比。‘土特拉’光合色素、光合作用和叶绿素荧光特性受对羟基苯甲酸影响小于‘全明星’和‘丰香’,维持较强的光合性能可能是对连作障碍具有较强抗性的生理基础。     

丛枝菌根真菌缓解对羟基苯甲酸抑制草莓生长的作用

以草莓为试材,采用接种丛枝菌根(AM)真菌和添加对羟基苯甲酸(PHBA)的方法,研究了根内球囊霉和摩西球囊霉对草莓自毒物质对羟基苯甲酸胁迫的缓解作用,即对草莓光合作用、根系结构和抗氧化物酶活性的影响。结果表明:0.5mmol·L~(-1) PHBA浓度时,接种根内球囊霉显著提高了草莓净光合速率、气孔导度、胞间CO_2浓度和蒸腾速率;摩西球囊霉显著提高了草莓的净光合速率、胞间CO_2浓度和瞬时水分利用效率;根内球囊霉明显提高了草莓实际光化学效率(Ф_(PSII))、荧光淬灭系数(qP)、电子传递速率(ETR);摩西球囊霉提高了Ф_(PSII)和ETR。0.5mmol·L~(-1) PHBA浓度时,根内球囊霉明显增加了草莓根长、根投影面积、根表面积、根体积、根尖数、根分叉数,摩西球囊霉显著增加了根长和根尖数。0.5mmol·L~(-1) PHBA胁迫下,2株AM真菌均明显提高了草莓根部超氧化物歧化酶、过氧化物酶、过氧化氢酶活性。2株AM真菌通过增强草莓光合能力、根系发育和提高抗氧化物酶活性缓解了PHBA对草莓的毒害作用,根内球囊霉改善根系结构和提高抗氧化物酶活性的效果较摩西球囊霉明显,可能与菌根侵染率相关。     

苯甲酸对豇豆种子萌发及抗氧化酶活性的影响

研究了不同浓度的苯甲酸对豇豆种子发芽、幼苗生长及抗氧化酶活性的影响。结果表明:随着苯甲酸浓度的增大,豇豆种子萌发率及豌豆幼苗的根长和苗长均呈降低的趋势。与对照相比,豇豆种子萌发率和豇豆幼苗的苗长均在苯甲酸浓度达到最大时受到显著抑制,而豇豆幼苗的根长在苯甲酸浓度最低时就受到显著抑制;随着苯甲酸浓度的增大,豇豆种子的抗氧化酶活性(SOD和POD)均呈降低趋势。10-5mol/L和10-6mol/L分别显著抑制了豇豆种子SOD和POD活性。     

酚酸类物质对嫁接伽师瓜植株生长及保护酶活性的影响

以嫁接在云南黑籽南瓜砧木上的伽师甜瓜为试材,探讨香草酸、香草醛和对-羟基苯甲酸为代表的酚酸类物质对嫁接伽师瓜植株和保护酶活性的影响。结果表明,3种酚酸物质对嫁接伽师瓜植株生长和产量没有显著抑制作用,而对自根伽师瓜植株的生长和产量产生明显的抑制作用,并随处理浓度的提高抑制作用明显增强,香草酸比香草醛和对-羟基苯甲酸具有更强的抑制作用;3种酚酸物质对嫁接伽师瓜根系的过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性的影响均呈现上升的趋势,并保持较高水平,而对照呈现先升后降的变化趋势,并显著低于处理。高浓度酚酸类物质使自根对照的丙二醛(MDA)含量增加。     

对羟基苯甲酸胁迫下尖孢镰刀菌侵染草莓根系的组织结构观察

以‘丰香’（Toyonoka）和‘土特拉’（Tutela）草莓品种为试材,利用石蜡切片技术研究了在自毒物质对羟基苯甲酸胁迫下,尖孢镰刀菌草莓专化型（Fusarium oxysporum f. sp. fragariae）侵染根系引起的组织结构变化。结果表明：对羟基苯甲酸胁迫下,尖孢镰刀菌菌丝在‘丰香’和‘土特拉’根系中的侵染速率明显加快,对根系表皮、皮层、中柱薄壁细胞及导管壁结构的破坏程度也明显加重,且对‘丰香’的破坏程度明显重于‘土特拉’。对羟基苯甲酸胁迫显著提高了‘丰香’和‘土特拉’根系组织含菌丝导管的比例,分别为22.5%和15.8%;但‘土特拉’根系含胶状物导管的比例为26.3%,明显高于‘丰香’（16.3%）。在对羟基苯甲酸胁迫下,‘土特拉’根系组织产生胶状物比‘丰香’早。‘土特拉’单独接菌处理根系内含有侵填体导管的比例为1.6%,明显高于‘丰香’单独接菌处理和对羟基苯甲酸胁迫下‘土特拉’接菌处理（1.0%和1.2%）。对羟基苯甲酸胁迫下接种尖孢镰刀菌可明显加重草莓根系组织受损程度,且‘丰香’枯萎病发生较重。     

不同调渗剂对番木瓜种子发芽特性及幼苗生长的影响

番木瓜是营养丰富并有医疗保健作用的蔬菜型水果。我国主要在海南、广东、广西、福建及台湾等热带、亚热带地区栽培。近年来番木瓜种植面积迅速扩大,并具有较好的经济效益。但番木瓜种子发芽速度慢,持续时间长,而且不整齐,发芽率和壮苗率低,给生产造成很大不利[1]。如何提高种子发芽力和壮苗率,是生产上亟须解决的问题。通过聚乙二醇(PEG)等渗透调节剂处理可促进种子萌发。已有研究结果表明:用PEG渗透种子,可以修补老化种子细胞膜,提高种子活力和出苗整齐度,促进幼苗生长,尤其是对一些小粒种子以及发芽迟缓出苗不齐的种子更有实用价值[2 …     

番木瓜遗传改良研究进展

就番木瓜的株性和抗病性等性状遗传、杂交育种、人工诱变育种、离体培养、分子标记及基因工程育种等现代生物新技术育种方面的研究进展及相关问题进行了评述,重点综述了番木瓜株性遗传、远缘杂交与胚胎学、基因工程在抗环斑型花叶病毒病(PRSV)品种培育及分子标记辅助选择育种应用的研究进展,并分析了今后番木瓜育种的发展趋势。     

Cloning and expression analysis of three genes encoding ubiquitins in papaya (Carica papaya L.)

Papaya (Carica papaya L.) fruit have a short shelf-life due to rapid ripening induced by ethylene, which usually results in a high percentage of product loss. However, little is known about the genetic mechanism of ripening and the attributes of fruit quality. Ubiquitin (UBQ) proteins have received increasing attention because they play important roles in response to ripening and in regulating certain developmental processes in plants. In the present study, three genes encoding UBQ proteins, CpUBI1, CpUBI2, and CpUBI3, were isolated from papaya fruit. The lengths of the cDNAs of CpUBI1, CpUBI2, and CpUBI3 were 1,485 bp, 1,642 bp, and 529 bp, encoding 306, 308, and 156 predicted amino acids, respectively. Sequence analysis demonstrated that the CpUBI1 and CpUBI2 proteins contained four consecutive structural domains of the UBQ superfamily, while CpUBI3 contained a ribosomal domain structure of the S27a superfamily. RT-qPCR analysis demonstrated that ethephon treatment increased CpUBI gene expression significantly, compared to 1-methylcyclopropene (1-MCP) treatment and the untreated controls. Levels of CpUBI1 and CpUBI2 gene expression were significantly higher than CpUBI3. These results suggested that CpUBI1, CpUBI2, and CpUBI3 might have different roles during papaya fruit ripening and softening.     

Sap flow in papaya plants: Laboratory calibrations and relationships with gas exchanges under field conditions

In papaya plants a study to quantify the water flow through the trunk is important for to promote a good water management in commercial orchard. The objective was to study the relationship between water flow through the trunk and temperature measurements determined by probes inserted in the papaya plant stem in laboratory. In addition, was possible to study the relationship between sap flow and instantaneous gas exchange in field conditions. We constructed an instrument that maintained a stable water flux through a 0.30 m stem section with a constant pressure, simulating the xylem sap flow through the stem. Water flux was adjusted by varying pressure of water in the stem section. The mathematical model used to fit the relation between K (Granier heat coefficient) values and sap flow density was the exponential model: u = 0.5511 × K^1.9104. Field studies was conducted in a commercial orchard located in North of the State of Rio de Janeiro, with 12 plants in October 2002, and eight plants in January 2003. We verified that instantaneous transpiration, measured by a portable system of gas exchange (porometry), presented a good (R² = 0.75) positive relationship with xylem sap flow. Estimates of papaya sap flow can be obtained by scaling portable photosynthesis system measurements with exposed leaves, however the relationship is non-linear in higher instantaneous transpiration rates. The causes of the non-linear relationship in higher transpiration are discussed. In addition, was possible to obtain a good (R² = 0.76) relationship between net photosynthesis rate and xylem sap flow in papaya field-grown.     

番木瓜内生细菌MG-Y2的鉴定及其生防作用

为筛选具有防病作用的植物内生菌,采用组织分离法和稀释分离法,分离番木瓜果皮中的内生细菌,得到103个菌株。采用培养基平板抑菌圈测定法从这些菌株中筛选到1株具有拮抗活性的细菌MG-Y2,对番木瓜疫霉病菌(Phytophthora nicotianae)、番木瓜炭疽病菌(Colletotrichum gloeosporioides)等8种病原菌有较强的拮抗作用。通过对其形态特征和生理生化特性测定以及16SrDNA部分序列同源性分析,鉴定该细菌为恶臭假单胞菌生物变种Ⅰ(Psudomonas putida biovarⅠ)。采用喷雾接种处理,MG-Y2可进入番木瓜叶片、叶柄、果皮和果肉中定殖。进行番木瓜果实采后防病试验,MG-Y2对采后番木瓜疫病和炭疽病的防治效果分别达到88.8%和57.4%。试验结果显示MG-Y2具有潜在的生防应用价值。     

番木瓜丝氨酸/苏氨酸蛋白激酶类抗病基因同源序列的克隆与特征分析

根据丝氨酸/苏氨酸蛋白激酶类抗病基因产物催化结构域Ⅰ和Ⅸ的氨基酸保守序列设计简并引物,PCR扩增番木瓜叶片基因组DNA和cDNA。在NCBI中用BlastX比对发现,5个来自基因组DNA的克隆和4个来自叶片cDNA的克隆可能编码的氨基酸残基序列属于STK蛋白激酶类抗病基因同源序列片段和受体样蛋白激酶基因的同源片段,命名为gPK1-gPK5和cPK1-cPK4,在GenBank注册得到序列号分别为AY693385-AY693389,AY738762-AY738765。除克隆gPK5含有内含子之外,其它都发现了连续阅读框ORF。通过分析除Gpk5之外的8个克隆可能编码氨基酸序列中丝氨酸/苏氨酸蛋白激酶类蛋白激酶的9个催化保守结构域Ⅰ-Ⅸ,并利用ClustalW软件对8个克隆和已报道的抗病蛋白水稻Xa21和西红柿Pto氨基酸残基序列进行分子系统进化树分析发现,8个克隆不仅是受体样蛋白激酶基因的同源片段而且是抗病候选基因片段。     

Breaking the intergeneric crossing barrier in papaya using sucrose treatment

A breeding programme was undertaken using Carica papaya var. Surya and Vasconcellea cauliflora with a view to raise progenies resistant to ‘papaya ringspot virus’ (PRSV). Earlier studies have clearly demonstrated the cross incompatibility between these two genera. Hence, an attempt was made to break this barrier using sucrose. The pollen of V. cauliflora was collected and pollination was carried out by smearing sucrose solution in the concentrations of 1, 2, 3, 4 and 5% on to the stigmatic surface of the flower. At 5% sucrose concentration, maximum viable seed set (13.73) was obtained. Sucrose at 5% was observed to break the intergeneric barrier by enhancing the pollen germination. There was drastic reduction in the effect of sucrose with the decrease in the concentration levels. The pollen germination studies carried out with and without sucrose clearly demonstrated the efficacy of sucrose in enhancing pollen germination and pollen tube growth. The intervarietal hybridization carried out between the varieties Surya and Pusa Dwarf showed 91.7% set of the fruits with 300 viable seeds per fruit. The hybridity of the progenies was confirmed using ISSR primers by the amplification of DNA from progenies and parents. Four primers UBC 807, 810, 814 and 861 clearly amplified male specific bands, which were present in progenies, but absent in female parent.     

葡萄白藜芦醇提取和HPLC定量测定适宜条件的研究

 研究了浸提溶剂种类、浸提方式、浸提温度和浸提时间对葡萄果皮和种子白藜芦醇(Res)提取的效果。结果表明, 果皮采用乙酸乙酯浸提溶剂, 研磨后25℃下浸提24 h, 种子采用甲醇浸提溶剂,研磨后25℃下浸提48 h, Res浸提效果最好。上述提取条件下, 采用高效液相色谱测定‘北醇’葡萄果皮和种子中的Res含量分别为3.51μg·g^{- 1} FM和8.81μg·g^{- 1} FM。反式Res在检测波长为306 nm条件下,采用等浓淋洗能很好地被检测到。     

HPLC法测定香菇中香菇嘌呤含量

建立1种运用高效液相色谱(HPLC)测定香菇(Lentinula edodes)中香菇嘌呤含量的方法。优化后的色谱条件为:Ultimate AQ-C18柱(5μm,4.6 mm×250 mm),流动相为甲醇-磷酸盐缓冲液(7∶93,pH 4.67)等度洗脱,流速1 mL/min,柱温30℃,检测波长259 nm,进样量10μL。研究结果发现该方法准确、灵敏、重现性好,适用于香菇嘌呤的定量分析。     

苹果树皮中12种酚类化合物的HPLC测定方法

【目的】为了建立高效液相色谱法(HPLC)同时测定苹果树皮中没食子酸、儿茶酚、儿茶素、绿原酸、咖啡酸、表儿茶素、香豆酸、阿魏酸、芦丁、根皮苷、槲皮素、根皮素12种酚类化合物的方法,【方法】选用Eclipse XDB C18色谱柱(150 mm×4.6 mm i.d,5μm),以甲醇和1%乙酸溶液作为流动相进行梯度洗脱,利用VWD检测器,在各种酚类物质的最优吸收波长下进行检测,【结果】得到12种酚类化合物的线性回归方程,相关系数均在0.999以上,检出限(3RSN)分别为0.02、0.02、0.03、0.01、0.02、0.03、0.01、0.01、0.03、0.03、0.05和0.01 mg.L-1。色谱测定方法和包含样品处理方法的加标回收率分别在56.54%～98.83%和90.95%～100.90%。【结论】整个提取和分析测定流程简便、快速、准确,适合苹果树皮中酚类化合物的分析测定。     

高效液相色谱法测定不同时期的日本楤木叶中芦丁含量

采用高效液相色谱法（HPLC）测定日本楤木叶中的芦丁含量。HPLC的最佳色谱条件：检测波长为360nm，流动相为甲醇：水=43：57，柱温30℃，流速1.0mL/min。在该条件下，芦丁在0.005~0.17mg/mL浓度范围内呈现良好的线性关系，平均加标回收率为100.6%，RSD为1.8%。测定结果表明，露天栽培与林下栽培的日本楤木叶中的芦丁动态累积趋势无明显差异，在8月份芦丁含量均达到最大值，分别为5.40mg/g和1.65mg/g。