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1.
常瑾  赵敬钊 《蛛形学报》2000,9(2):116-121
应用 二次正交旋转组合设计方法,对稻田生态系统中3种捕食性天敌(三突花蛛Misumenops tricuspidata(Tabricius)、草间钻头蛛Hylyphantes graminicora(Sundevall)、真水狼蛛Pirata piraticus(Clerk)和1种害虫(白背飞虱Sogatella furcifera(Horvath)的共存系统进行研究,获得了天敌对害虫控制作用的数  相似文献   
2.
为探讨柘叶Cudrania tricuspidata饲养家蚕Bombyx mori易感染核多角体病毒(BmNPV)的机制, 本实验比较研究了分别以柘叶和桑叶Morus alba饲养家蚕后其消化液中抗病毒蛋白活性的差异。结果表明: 家蚕经柘叶饲养后消化液中红色荧光蛋白(red fluorescent protein, RFP)的强度无明显变化, 但柘叶饲养蚕消化液中脂肪酶、 胰蛋白酶的活性显著低于桑叶饲养蚕, 柘叶饲养蚕消化液中脂肪酶和胰蛋白酶的活性分别为1 421.71±202.60 U/L和19.67±8.17 U/mL, 桑叶饲养蚕脂肪酶和胰蛋白酶的活性分别为1 976.03±139.92 U/L和199.18±181.71 U/mL。这些结果说明, 消化液中脂肪酶和胰蛋白酶的活性水平低与柘叶饲养蚕易感染核型多角体病毒(BmNPV)可能相关。  相似文献   
3.

Background and Aims

Cold neutron radiography was applied to directly observe embolism in conduits of liana stems with the aim to evaluate the suitability of this method for studying embolism formation and repair. Potential advantages of this method are a principally non-invasive imaging approach with low energy dose compared with synchrotron X-ray radiation, a good spatial and temporal resolution, and the possibility to observe the entire volume of stem portions with a length of several centimetres at one time.

Methods

Complete and cut stems of Adenia lobata, Aristolochia macrophylla and Parthenocissus tricuspidata were radiographed at the neutron imaging facility CONRAD at the Helmholtz-Zentrum Berlin für Materialien und Energie, with each measurement cycle lasting several hours. Low attenuation gas spaces were separated from the high attenuation (water-containing) plant tissue using image processing.

Key results

Severe cuts into the stem were necessary to induce embolism. The formation and temporal course of an embolism event could then be successfully observed in individual conduits. It was found that complete emptying of a vessel with a diameter of 100 µm required a time interval of 4 min. Furthermore, dehydration of the whole stem section could be monitored via decreasing attenuation of the neutrons.

Conclusions

The results suggest that cold neutron radiography represents a useful tool for studying water relations in plant stems that has the potential to complement other non-invasive methods.  相似文献   
4.
光合性能选种法研究   总被引:1,自引:0,他引:1  
生物良种的选择,历来是人类最关心的事,本文讨论的是植物的选种方法,我们在品质基本相同的几个品种中选择最优品种.这里最优品种指的就是产量最高者.植物的产量是由光合作用所产生的生物量,所以,光合性能强的物种常为最优品种.本文所介绍的选种方法,就是根据不同品种的光合性能的强弱来研究品种的优劣,而植物光合性能强弱可以通过植物的光合总量来确定.本文计算了三个猕猴桃品种的光合总量,其中光合总量最高者为最优品种(产量最高),这与生产实践完全一致,所以光合性能选种法得到了生产实践的验证.  相似文献   
5.
野生软枣猕猴桃总黄酮含量的测定   总被引:10,自引:0,他引:10  
利用分光光度法,测定了软枣猕猴桃中总黄酮的含量,建立了芦丁浓度-吸光度关系的回归方程.  相似文献   
6.
地锦属植物抗寒性生理指标变化分析   总被引:1,自引:0,他引:1  
通过对五叶与三叶地锦人工低温梯度冷冻处理取样、自然露地越冬和春秋冻融季节取样处理,分别测定实验材料抗寒理化指标的变化规律,研究其抗寒机制与抗寒能力。通过Excel做图处理和SAS数据软件显著性分析,结果表明,可溶性糖与蛋白质含量与电导率的数值随温度的降低呈单峰曲线变化,数据量值差异显著或极显著,在冬季和人工最低温时均达到最高值,POD在秋季和春季保持较高的酶活性,尤其在春季酶活性最高;春季的冻融交替对实验材料的伤害强于秋季;五叶地锦的半致死温度为-26.89℃,三叶地锦的半致死温度为-24.07℃,五叶地锦的抗寒能力、露地越冬能力强于三叶地锦;实验材料在哈尔滨市寒冷的环境中具有一定的越冬能力;实验材料露地越冬后的生长表现与实验结论相一致。  相似文献   
7.
Eleven compounds were isolated from the twigs and leaves of Rourea microphylla (Hook. et Arn) Planch. They were identified as quercetin-3-O-α-L-rhamnopyranoside (Ⅰ), hyperin (Ⅱ), quercetin (Ⅲ), astilbin (Ⅳ), β-sitosterol (Ⅴ), β-sitosteryl-β-D-glucopyranoside (Ⅵ), physcion (Ⅶ), erythroglaucin (Ⅷ), stearic acid (Ⅸ), palmitic acid (Ⅹ) and n-nonacosanane (Ⅺ) respectively, by means of UV, IR, NMR, MS spectra analyses and through chemical methods. The compounds Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅵ, Ⅶ, Ⅷ, Ⅸ, Ⅹ and Ⅺ were first reportedin the Rourea genus.  相似文献   
8.
爬山虎红色素的大孔树脂吸附和分离及理化性质研究   总被引:4,自引:0,他引:4  
本文比较了六种不同型号的大孔树脂对爬山虎红色素的吸附能力,筛选其中最佳的HPD600树脂作为爬山虎红色素的吸附和分离的树脂;用甲醇作为洗脱剂,洗脱效果好;研究了食品中几种常见的共存物、几种金属离子、氧化剂、温度及光等对爬山虎红色素稳定性的影响。  相似文献   
9.
The growth of crown-gall cells cultured in vitro ( Nicotiana tabacum L. cv. White Burley and Parthenocissus tricuspidata cv. Veitchii) is inhibited by alstonine (BG-8), a plant alkaloid, the anti-cancer effect of which has previously been demonstrated on animals and plants. The growth of normal cells is only slightly affected. The inhibitory effect of BG-8 on crown-gall cells is antagonized by indole-3-acetic acid (IAA) added to the culture medium. Kinetin associated with IAA does not prevent this inhibitory effect. BG-8 present in the culture medium containing the two types of hormones seems to modify the later hormonal requirement of Parthenocissus crown-gall tissues.
BG-8 exhibits high binding affinity for crown-gall DNA and, therefore, strongly inhibits its in vitro synthesis. The alkaloid has practically no effect on DNA from healthy cells. The inhibition by BG-8 is dependent on the level of DNA strand separation and on the origin and nature of the tissues (crown-gall DNA is more destabilized than healthy DNA; DNA from habituated tissues is intermediate). IAA and kinetin have opposite effects on the in vitro strand separation of the DNAs from crown-gall cells and, consequently, antagonistic effects on DNA replication (IAA stimulates and kinetin inhibits). It is possible to establish a close relationship between in situ development of crown-gall tissues of the two species studied (in the presence or absence of BG-8 or cell-growth factors), in vitro DNA synthesis and DNA strand separation.  相似文献   
10.
采收期和贮藏温度对金艳猕猴桃品质的影响   总被引:4,自引:0,他引:4  
研究了金艳猕猴桃(Actinidia chinensis ×A. eriantha) 4个不同采收期(Ⅰ~Ⅳ)在常温[(23±1)℃]贮藏60 d,以及低温(4℃)贮藏2、4、6月后常温货架14 d内果实品质和果肉色彩的变化。结果表明:采收期Ⅰ和Ⅳ的果实在常温贮藏过程中呼吸高峰出现早、失重快,可滴定酸(TA)、维生素C(Vc)含量和果肉硬度迅速下降;而采收期Ⅱ和Ⅲ的果实呼吸高峰出现晚,保持了较高的TA、Vc含量和果肉硬度。4个采收期猕猴桃果实在常温贮藏期间,果实亮度L*、色度C*和色彩角h显著降低;而在低温贮藏后常温货架期间,果实色彩角h相对于亮度L*和色度C*变化更加明显。研究表明,采收期Ⅱ和Ⅲ为金艳猕猴桃的适宜采收期,色彩角h可以作为适宜的指标反映猕猴桃果实的后熟与衰老,而低温贮藏6个月金艳猕猴桃仍能保持较好的食用品质和色彩。  相似文献   
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