三个柠檬品种果实非可食部分初生代谢产物分析

为了比较贵州产尤力克柠檬、四季柠檬和阿特摩柠檬果实非可食部分初生代谢产物差异,本研究采用GC-MS分析了3个柠檬成熟果实非可食部分氨基酸、有机酸和糖等初生代谢产物含量。结果表明,共检测到29个初生代谢产物,其中氨基酸8个、有机酸11个、糖10个,不同柑橘品种不同组织氨基酸、有机酸、糖等初生代谢产物种类和含量存在较大的差异。3个品种均是脯氨酸含量最高;3个品种有机酸种类相似,黄皮层和白皮层含量最高的为奎宁酸,而囊衣含量最高的为柠檬酸。对检测的糖类而言,均是葡萄糖含量最高。     

柠檬花粉形态的初步观察

利用扫描电子显微镜观察10份柠檬种质的花粉形态,500倍观察花粉粒群体,3000倍观察赤道面和极面,10000倍观察外壁纹饰。结果表明：10份柠檬种质的花粉类型均属于单粒花粉,外观形态为长球形、近球形和扁球形三类,大小等级为小的花粉,萌发孔沟4～5条,沟长均直达两极,沟沿极轴方向等距环状分布,外壁纹饰均属于网状雕纹。10份柠檬种质两两之间在花粉极轴长、赤道轴长、萌发沟数量及外壁纹饰上,均存在一个或者一个以上的极显著差异或显著差异,因此,可作为不同柠檬种质之间鉴定的依据。     

柑橘抗逆基因NAC83的克隆与表达分析

以柚[Citrus maxima（Burm.）Merr.]、枳[Poncirus trifoliata（L.）Raf.]和柠檬[C. limon（L.）Burm. f.]实生苗为试材,使用电子克隆和RT-PCR的方法从中克隆到3个新的NAC蛋白基因,分别命名为CmNAC83、PtNAC83和ClNAC83;并用qRT-PCR技术检测了该基因在ABA、干旱、低温和高盐胁迫处理下的时空表达。结果显示：CmNAC83、PtNAC83和ClNAC83 的cDNA序列全长均为841 bp,都含有750 bp的开放阅读框（ORF）,编码249个氨基酸;推测其蛋白分子质量分别为24.18、28.00和28.15 kD,等电点分别是9.02、9.31和9.30,且均含有NAC家族的N端保守结构域;系统进化树分析表明,该3个蛋白均属于SENU5亚族,与苹果NAC22亲缘关系较近。实时定量qRT-PCR分析显示,NAC83基因能被ABA、干旱、低温和高盐胁迫诱导表达,且在不同的柑橘种类中存在表达差异。可见柚CmNAC83、枳PtNAC83和柠檬ClNAC83是NAC基因家族的成员,可能在柑橘响应非生物胁迫的过程中起了重要作用。     

3个柠檬品种在云南干热河谷区的光合特性及结果性能分析

\t\t\t\t\t目的\t\t\t\t\t通过比较300、420、800、1 110 m海拔下尤力克柠檬(Eureka lemon)的光合特性,为尤力克柠檬最适宜栽培海拔高度及布局提供依据。\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t以云南红河流域、勐旺4个不同海拔区域种植的尤力克柠檬为研究对象,测定比较环境因子变化、光合相关参数[净光合速率(P_n)、胞间CO₂浓度(C_i)、气孔导度(G_s)、蒸腾速率(T_r)]变化和光响应曲线。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t(1) 4个海拔区域尤力克柠檬的光合有效辐射和大气温度均呈单峰型变化曲线,叶表面的相对湿度呈低谷型变化曲线,峰值和低谷均在12：00。(2) 4个海拔区域尤力克柠檬的净光合速率均呈单峰型变化曲线,随着海拔的升高呈增加趋势,到1 110 m出现下降。800 m和1 110 m显著高于420 m和300 m的净光合速率。(3)光响应曲线的拟合结果表明：最大净光合速率和表观量子效率的大小均为800 m>1 110 m>420 m>300 m。\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t4个海拔区域柠檬光合特性为800 m>1 110 m>420 m>300 m,即这4个区域中,最适宜种植尤力克柠檬的海拔为800~1 110 m。\t\t\t\t     

施肥量对柠檬幼树矿质养分、产量及品质的影响

连续3年开展不同施肥水平对柠檬幼树养分含量及果实产量、品质影响的研究,以期筛选出柠檬幼树适宜的经济施肥量。每株每月分别施用柠檬幼树专用肥0(CK)、10、20、40、80、160 g,测定各处理叶片、果实、果皮、果肉的矿质养分含量,每年统计单株产量及果实品质,探讨施肥量对矿质养分吸收和果实产量、品质的影响。结果表明,施肥能显著增加叶片和果实N、Mg、Zn、Mn、Cu、Fe含量。随着施肥量的增加,P、K含量先降低后增加,Ca、Mg、Fe含量则呈相反趋势,为先增加后减少。不同施肥处理3年总产量表现为40 g>20 g>10 g>80 g>0 g>160 g;肥料用量为40 g时的产量和品质最佳,其产量是对照的9.62倍,可食率、出汁率、可溶性固形物、维生素C、可滴定酸分别增加26.97%、7.37%、38.21%、21.57%、39.38%。综合考虑植株的养分、产量和果实品质情况,推荐柠檬幼树生长中每株每月施用柠檬专用肥40 g。     

Fumigant toxicity of lemon eucalyptus oil constituents to acaricide-susceptible and acaricide-resistant Tetranychus urticae

BACKGROUND: This study was aimed at assessing the fumigant toxicity of 14 essential oil constituents from lemon eucalyptus, Eucalyptus citriodora Hook, and another ten known compounds to females of acaricide‐susceptible, chlorfenapyr‐resistant, fenpropathrin‐resistant, pyridaben‐resistant and abamectin‐resistant strains of Tetranychus urticae Koch. RESULTS: Menthol (LC₅₀, 12.9 µg cm^?3) was the most toxic compound, followed by citronellyl acetate (16.8 µg cm^?3), against the susceptible females. High toxicity was also produced by β‐citronellol, citral, geranyl acetate and eugenol (LC₅₀, 21.7–24.6 µg cm^?3). The fumigant toxicity of these compounds was almost identical against females from either of the susceptible and resistant strains, indicating that the compounds and acaricides do not share a common mode of action or elicit cross‐resistance. CONCLUSION: Global efforts to reduce the level of highly toxic synthetic acaricides in the agricultural environment justify further studies on materials derived from lemon eucalyptus oil, particularly menthol and citronellyl acetate, as potential acaricides for the control of acaricide‐resistant T. urticae as fumigants with contact action. Copyright © 2011 Society of Chemical Industry     

Improved growth of salinity-stressed citrus after inoculation with mycorrhizal fungi

The present investigation was conducted during 2006 and 2007 growing seasons in order to study the effects of different salinity levels on the growth and chemical composition of sour orange and Volkamer lemon rootstocks. Besides, this research was also undertaken to elucidate the efficiency of mycorrhizal colonization on controlling the various hazards accompanying salinity stress. One-year-old sour orange and Volkamer lemon rootstocks were kept in a glasshouse and irrigated with control (non-saline), 1500 ppm, 3000 ppm and 4500 ppm of salinity levels. Salinity decreased arbuscular mycorrhizal (AM) colonization. In both the AM and non AM, leaf area, trunk cross-sectional area, total, top, leaf and root dry weights were decreased under salinity. The plants inoculated with the AM fungus had significantly higher growth parameters compared to the non-inoculated plants. Increasing the salinity level tended to increase the concentrations of leaf Na, N, Ca and Cl while P, K, Mg, Fe, Mn, Zn and Cu decreased. On the contrary, inoculating the seedlings with AM tended to increase the levels of P, K, Mg and Zn. Whereas leaf N, Ca and Na of inoculated seedlings was significantly lower than that of un-inoculated ones. Leaf Cl, Fe, Mn and Cu contents did not statistically vary in this concern.     

转chit42基因柠檬的分子鉴定及抗炭疽病研究

以转chit42基因柠檬为试材,对其进行了分子鉴定和抗炭疽病研究。用PCR和Southern杂交证实外源基因chit42已经整合到转化植株基因组中,chit42基因在转基因柠檬SR23株系中为3个拷贝,在SR24株系中为2个拷贝。对转基因柠檬进行离体和活体抗炭疽病试验表明转基因柠檬抗炭疽病能力得到明显提高。利用半定量RT-PCR技术检测chit42基因在柠檬中的表达,结果表明用炭疽病病菌接种处理24h后,chit42基因表达量开始增加;接种48h后,chit42基因表达量进一步明显增大;接种72h后,表达量开始有所下降,但仍然高于正常情况下chit42基因的表达量。     

湿热区柠檬枝梢类型对花果及其品质的影响

研究不同枝梢形态对柠檬花果发育的影响,以期为柠檬高产优质栽培提供理论依据。选择7 a生‘云柠1号’尤力克柠檬为材料,针对柠檬不同枝梢类型（带叶无新梢枝梢、无叶枝梢、带叶有新梢枝梢）,开展其开花、果实发育动态、产量及品质研究。结果表明：带叶有新梢枝梢较带叶无新梢枝梢有更长时间的营养生长,带叶无新梢枝梢比带叶有新梢枝梢会更早的进入生殖生长,其原因是带叶有新梢枝梢新梢生长需要更多的同化产物,新梢的生长分流掉一部分由老叶供给的养分,所以其营养生长的时间要更长,而带叶无新梢枝梢因无新梢分流养分而提早进入生殖生长。带叶有新梢枝梢上的果实比带叶无新梢枝梢上的果实果大、可溶性固形物和Vc含量也都有显著的提高,原因是果台副梢对果实大小、可溶性物质和Vc均有促进作用。柠檬在第一、二次生理落果后,带叶枝梢着果率高于无叶枝梢,但其果实VC含量却低于无叶枝梢,原因是有叶枝梢具有足够的叶面积和光合能力强,为早期果实的发育提供营养。同时也正由于无叶枝梢的挂果率低,使得果实间对同化产物的竞争力小,果实Vc含量反而高于带叶枝梢。     

Effects of dietary dehydrated lemon peel on some biochemical markers related to general metabolism,welfare and stress in gilthead seabream (Sparus aurata L.)

Dehydrated lemon peel (DLP) at two levels (1.5% and 3%) was included for 30 days in the diet of gilthead seabream (Sparus aurata L.) and after 15 and 30 days the serum and skin mucus of fish were analysed. In serum, both experimental diets led to an initial decrease in glucose and lactate after which the levels became comparable to the control. Dietary DLP modulated the activity of transaminases, alanine aminotransferase and aspartate aminotransferase. The total antioxidant status showed a progressive increase in relation to levels of inclusion of DLP and time of administration (p < .05). In skin mucus, some biomolecular markers related to general stress, oxidative stress and apoptosis exhibited variations that suggest an adaptive response of fish to the new metabolic situation, resulting from the experimental diet. The inclusion of DLP in the diet seems to positively modulate the central metabolism and welfare of gilthead seabream.