不同温度下六斑月瓢虫对桃蚜功能反应的研究

通过不同温度下六斑月瓢虫对桃蚜的捕食量,进行了Holling-Ⅱ型和Holling-III型功能反应模型拟合,结果表明,六斑月瓢虫的发现率和最大捕食量随温度升高而增大,平均处理时间随温度升高而减少,表明高温有利于六斑月瓢虫的捕食。同时对六斑月瓢虫的利用进行了探讨。表2,参5。     

Selection for resistance to azadirachtin in the green peach aphid,Myzus persicae

Two lines ofMyzus persicae of the same origin were treated repeatedlywith pure azadirachtin (aza), or a refined neem seed extract (NSE), at the equivalent concentration of aza. After 40 generations, the aza-selected line had developed 9-fold resistance to aza compared to a non-selected control line, whereas the NSE-selected line did not. These results suggest that a blend of active constitutents in a botanical insecticide such as neem might diffuse the selection process, mitigating the development of resistance compared to that expected with a single active ingredient.     

超声波处理对不同品种桃果实贮藏品质变化的影响

采用频率为50kHz输出功率为200W的超声波分别对“大久保”桃和“八月脆”桃进行处理,处理时间分别为1min、5min和10min,研究了以桃果实在(10±2)℃条件下贮藏13d的品质变化情况。结果表明:超声波处理5min可明显降低两个品种桃的腐烂率,且5min处理可明显降低“大久保”桃前期果肉硬度的下降,到后期两个品种桃5min处理的酸含量均较高。     

Novel substrates for the kinetic assay of esterases associated with insecticide resistance

Naphthalene thioesters were synthesized as substrates for a continuous, non- disruptive kinetic assay of general carboxylesterase activity. The continuous nature of the assay is based on the production of a soluble dianion chromophore from the reaction of naphthalene thio with 5,5-dithiobis (2-nitrobenzoic acid). Applications with 1- and 2-naphthalene thioacetates demonstrated their use in a fast accurate kinetic microassay of esterase activity, using porcine carboxylesterase as a model. These novel esters proved to be useful as substrates for the spectrophotometric assay of insecticide-resistance in two aphid species and may be applicable to other esterasebased diagnostic procedures.     

Functional characterization and mapping of two MADS box genes from peach (Prunus persica)

Previously an AGAMOUS gene homologue PpMADS4 and a FRUITFULL gene homologue PpMADS6 were isolated from peach (Prunus persica), and both genes were shown to express in the developing floral and fruits. To gain insight into their function, the two genes were constitutively expressed in Arabidopsis thaliana and their effects on plant growth and floral organ development were studied in this work. The transgenic plants all displayed early flowering and conversion of inflorescence to floral meristem. However, the two genes had different effects on the floral organ structures in A. thaliana. The transgenic plants overexpressing PpMADS4 displayed homeotic conversion of floral organs, and par- ticularly the perianth abscission was inhibited. The plants overexpressing PpMADS6 showed early flowering, produced higher number of carpels, petals, and stamens than nontransgenic plants, and pod shatter was prevented; significantly, the transgenic plants yielded more than one siliques from a single flower. A SSR molecular marker was developed for PpMADS4, and it was then assigned into the G5 linkage group of Prunus sp. Both PpMADS4 and PpMADS6 genes were located at the same region in the G5 linkage group. Our results showed the potential application of these two MADS box genes for crop and fruit tree improvement.     

晚蜜桃离体培养初探

采用对比试验设计,进行了晚蜜桃的离体培养。结果表明:MS+6-BA1.0mg·L-1+IAA0.2mg·L-1培养基较适宜初代培养,MS+6-BA1.5mg·L-1+IBA0.2mg·L-1+IAA0.2mg·L-1培养基较适宜继代培养。     

赤霉素对西农早蜜桃果实发育的影响

探讨了用赤霉素(GA3)处理西农早蜜对果实发育的影响。试验结果表明：在盛花后30d用50ppm、100ppm、150ppm GA3液处理桃幼果，可使果实膨大并增加果重，显著地提高其果实的糖酸比及硬度，但对果实维生素C含量和着色率无明显影响。     

1株桃果实采后病原真菌的鉴定 以及碳源代谢指纹图谱分析

从采后贮藏过程中发病的八月脆桃果实(Amygdalus persica cv.Bayuecui)中分离到1株真菌菌株074#.通过对病原菌形态学观察以及核糖体ITS rDNA序列分析,证明菌株074#为灰葡萄孢霉菌(Botrytis elliptica).致病性试验结果表明,桃果实为灰葡萄孢霉菌的寄主.通过Biolog FFMicroPlate分析该病原菌对95种碳源的利用能力,结果表明,Botrytis elliptica代谢指纹图谱为最适碳源包括D-果糖、蔗糖、L-苹果酸、琥珀酸、D-葡萄糖酸、L-天门冬氨酸、L-丝氨酸、腺苷、5'-磷酸腺苷等26种,可利用碳源14种,不可利用碳源55种.     

《桃花源记》的桃花流水原型

陶渊明《桃花源记》描写了桃花意象和流水意象。桃花流水意象的描写受到了魏晋间表现灵异变化故事的影响,因而具有原型意义。《桃花源记》的桃花流水原型象征了桃花源世界的平安、幸福与长寿。     

NaHSO_3在桃树上的应用基础研究

不同浓度ＮａＨＳＯ３在桃树上的应用研究表明，以１００ｐｐｍ效果最佳。于果实膨大期处理３次，能明显提高桃树座果率，单果重，促进新梢生长，改善品质。作者认为，此与ＮａＨＳＯ３多重生理效应相关