重庆万州柑橘轮斑病菌的鉴定及防治药剂筛选

【目的】明确2018年起在重庆万州柑橘种植区新发生病害的病原菌,筛选有效防控药剂,为田间防治该病害和后续深入研究提供理论参考。【方法】通过组织分离法从患病样品中获得菌株,进行病原菌形态学、分子生物学和致病性鉴定,采用生长速率法测定不同药剂对目标菌株的毒力。【结果】此病害的病原菌为柑橘轮斑病菌Pseudofabraea citricarpa。病原菌对万州地区主栽的8个品种柑橘的叶、枝、果和昭通苹果及砀山酥梨果实具有致病性。苯醚甲环唑、咪酰胺、甲基硫菌灵等17种杀菌剂的EC50值小于3 mg/kg,代森锰锌与啶酰菌胺1：64比列复配、克菌丹与苯醚甲环唑1：1比例复配、代森锰锌和矿物油1:50比例复配对菌株生长抑制效果良好。【结论】重庆万州柑橘种植园区发生柑橘轮斑病,病原菌对柑橘枝、叶、果和其它果树果实都具有致病性。17种药剂单用或复配对病原菌生长有抑制作用,可进一步用于田间实验。     

马家柚粗皮果形成过程的解剖学观察

为了解马家柚粗皮果形成的原因,以马家柚光皮果为对照,比较了果实发育期间果皮的显微结构。通过对外果皮的解剖结构观察发现,光皮果的油胞下凹,而粗皮果的油胞略有凸起,并且粗皮果的油胞体积明显大于光皮果,二者在油胞上所表现的这些差异可能是导致粗皮果果皮粗糙的主要原因。通过对中果皮的解剖结构观察发现,在果皮成熟时粗皮果中果皮细胞较光皮果形态上更细长,果皮射线方向细胞直径更大,细胞间隙也更大,这些可能是导致粗皮果果皮增厚、海绵层疏松现象的原因之一。     

甜橙bHLH转录因子家族的鉴定及生物信息学分析

bHLH转录因子家族是第2大转录因子家族,广泛存在于微生物、植物以及动物中。以甜橙为试验材料,通过全基因组数据库搜索鉴定,对bHLH基因进行了理化性质、系统发育、染色体分布、保守基序、蛋白互作生物信息学分析,探讨它们在不同组织的表达情况。结果表明：共鉴定出126个bHLH基因,其中112个不均匀的分布于9条染色体上,14个分布位置尚未确定;系统发育分析表明甜橙bHLH基因家族可分为16个亚家族,并且给定亚家族中的大多数基因具有相似的基因结构和保守基序。在甜橙中,多个bHLH基因相互作用共同调控其开花、光的形态发生和花色素苷合成等过程;大多数的CsbHLH基因在愈伤组织、叶、花和果实中均有表达。本研究为CsbHLH基因的功能研究奠定了基础,并有助于bHLH基因在其他植物物种中的功能研究。     

Characterization of citrus germplasm including unknown variants by inter-simple sequence repeat (ISSR) markers

Inter-simple sequence repeat (ISSR) markers were used to study phylogenetic relationships among 33 citrus genotypes including several undefined local or native varieties as well as some known varieties in the Fars Province of Iran.     

桔园生草对丛枝菌根形成及果实品质的影响

试验以枳砧温州蜜柑成年树为试材。试验设土壤水分胁迫下百喜草生草区和清耕区2个处理,以清耕加轻度灌水为对照,4次重复。结果表明利用高菌根侵染率的百喜草在柑桔园进行生草管理,在土壤水分胁迫下,显著地提高了柑桔根系丛枝菌根侵染率及土壤丛枝菌根菌孢子数。菌根侵染率的提高改善了柑桔果实的品质,特别是促进了柑桔果皮的着色。生草管理还蓄养了土壤水分。     

QuEChERS-三重四极杆串联质谱测定柑橘中农药基质效应的方法研究

[目的]针对柑橘中常用的农药,采用QuEChERS方法和超高效液相色谱-三重四极杆串联质谱,系统研究了其测定过程中的基质效应.[方法]柑橘样品利用乙酸-乙腈溶液(V︰V=1︰99)提取、GCB净化,采用甲醇-0.1％甲酸水溶液(含1mmol·L-1乙酸铵)作为流动相,正离子多反应监测(MRM)模式,基质外标法定量,可以...     

Comparison of nuclear DNA content of citrus rootstock populations by flow cytometry analysis

Citrus species are widely grown in the world. Plant characteristics of the rootstock populations used for orange, lemon, mandarin and grapefruit cultivars should be known as well as those of the cultivars that help true‐to‐type nursery plant production. In this study, cell nuclei were isolated from leaf tissues of seedlings of trifoliate orange, sour orange, rough lemon,‘Volkamer’ lemon,‘Cleopatra’ mandarin,‘Hyokan’, ‘Sanbokan’, ‘Kinkoje’, ‘Carrizo’ citrange and ‘Swingle’ citrumelo, and then fluorescence intensities were measured on propidium iodide‐stained nuclei by flow cytometry. Nuclei isolated from the triploid ‘Tahiti’ lime with a known nuclear genome size were used as the internal standard to estimate the nuclear DNA content of Citrus seedling populations in absolute units. Results obtained from cytograms and histograms indicated that all seedlings analyzed were diploid. In addition, differences between the species for nuclear DNA content were also found to be significant. ‘Hyokan’ seedlings had the biggest genome size, 0.984 pg/2C, whereas trifoliate orange seedlings had the smallest genome size, 0.678 pg/2C. Flow cytometry analysis could be used for obtaining accurate and rapid results for cytological observations of seedling populations of Citrus.     

16个柑桔品种的光合特性

试验研究了 16个柑桔品种的光合速率、光饱和点、光补偿点及光合速率的日变化规律。结果表明 ,供试的 16个柑桔品种的光合速率、光饱和点和光补偿点存在差异 ,其大小顺序为 :清见橘橙 >清家脐橙 >红肉脐橙 >丰脐 >姊良 3号脐橙>德尔塔夏橙 >卡特 >大三岛脐橙 >纽荷尔脐橙 >梦脐橙 >白柳脐橙 >红夏橙 >铃木脐橙 >福罗斯特脐橙 >Fallago橘>朋娜脐橙。大三岛脐橙、红夏橙的光饱和点最高 ,红肉脐橙、姊良 3号脐橙、梦脐橙、朋娜脐橙、白柳脐橙、德尔塔夏橙、卡特夏橙、清见橘橙、福罗斯特脐橙次之 ,纽荷尔脐橙、丰脐、铃木脐橙、Fallago橘较低 ;16个柑桔品种光补偿点在 8.4～6 6 .5μmol m- 2 s- 1 之间 ,福罗斯特脐橙的光补偿点最高 ,姊良 3号脐橙、朋娜脐橙、大三岛脐橙、德尔塔夏橙次之 ,其它柑桔品种光补偿点较低。供试柑桔品种在晴天光合速率的日变化均呈双峰曲线 ,中午有明显的“午休”现象。     

Assessment of genetic variability in grapefruits (Citrus paradisi Macf.) and pummelos (C. maxima (Burm.) Merr.) using RAPD and SSR markers

The genetic variability of 38 grapefruit (Citrus paradisi Macf.) and three pummelos (C. maxima (Burm.) Merr..) accessions was evaluated using RAPD, and single sequence repeat (SSR) analyses. Approximately49% of the 198 RAPD were polymorphic, and 4.6 alleles per SSR loci were identified. PIC values changed from 0.093 to 0.450. A UPGMA phenetic tree was constructed and two main grapefruit groups were identified. The grapefruit accessions `do Cabo' and `Siamesa-Filipinas'clustered very close to the pummelos in Group A. The Group B consisted of three sub-groups, which comprised all of the other grapefruit accessions. The majority of grapefruit accessions showed a narrow genetic base suggesting that the observed morphological polymorphism within the group must be associated with somatic mutations, which were not detected by these molecular markers. This revised version was published online in August 2006 with corrections to the Cover Date.     

Blue light alters infection by Penicillium digitatum in tangerines

The effect of blue light exposure on Penicillium digitatum infection of tangerines during postharvest storage was investigated. In citrus, P. digitatum is one of the most important fungi causing diseases that result in postharvest loss. There is increasing interest in development of environmentally sustainable and consumer-friendly strategies of decay control. Strategies based on a plant's immunity can minimize pathogen infection of fruit. Light signalling affects plant-pathogen interactions and blue light may modulate phospholipase activation, a key step in plant immune responses. Exposure of fruit to 410-540 nm blue light at a fluency of 40 μmol m⁻² s⁻¹ reduced infection by P. digitatum and induced phospholipase A₂ (PLA₂) gene expression. Inhibition of PLA₂ activity allowed infection, whereas inhibition of phospholipase D (PLD) expression by 580-670 nm red light at the same fluency was correlated with infection. These data strongly suggest that induction of lipid signalling by light reduces fungal colonization by P. digitatum in citrus fruit.