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1.
EMMA DESPLAND MARIA GUNDERSEN SIMON P. DAOUST BRIAN J. MADER NATHALIE DELVAS PAUL J. ALBERT ERIC BAUCE 《Physiological Entomology》2011,36(1):39-46
The pattern of feeding of Eastern spruce budworm Choristoneura fumiferana (Clem.) (Lepidoptera, Tortricidae) is compared on foliage from white spruce Picea glauca (Moench) Voss. (Pinaceae) trees previously determined to be susceptible and resistant to defoliation by budworm. No differences are observed in electrophysiological responses from taste sensilla to aqueous extracts of the two foliage types, nor is there a preference for either extract type in a choice test. Acetone extracts from the two foliage types are both preferred to a control sucrose solution, although neither elicits a preference relative to the other. These results suggest that there is no difference in phagostimulatory power of internal leaf contents of the two foliage types. Longer‐term observation of feeding behaviour in a no‐choice situation shows no difference in meal duration, confirming the lack of difference in phagostimulatory power. However, on average, intermeal intervals are twice as long on the resistant foliage, leading to an overall lower food consumption during the assay. This result suggests an anti‐digestive or toxic effect of the resistant foliage that slows behaviour and limits food intake. Previous research has shown that waxes of the resistant foliage deter initiation of feeding by the spruce budworm and that this foliage contains higher levels of tannins and monoterpenes. The data suggest that the resistant foliage contains a post‐ingestive second line of defence against the spruce budworm. 相似文献
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紫胶虫的4种寄主树钝叶黄檀、南岭黄檀、木豆和苏门答腊金合欢的次生韧皮部轴向系统均由筛管、伴胞、韧皮薄壁细胞、纤维组成,径向系统由射线组成。木豆、苏门答腊金合欢中尚有少量石细胞。苏门答腊金合欢筛管分子端壁较倾斜,具复筛板,无明显的 P-蛋白质。其余3种筛管分子端壁均为横向,具单筛板,具 P-蛋白质。根据观察结果分析,4种寄主树2—3年生枝条或具表皮,或木栓层很薄;次生韧皮部的筛管看来均具相对较长的寿命;4种寄主中有3种筛管与伴胞均属特化程度高的类型。 相似文献
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应用光学显微镜对白毛新木姜子的胚胎学特征进行了研究,首次在非寄生性樟科植物中发现了细胞型胚乳。对樟科8属进行了胚胎学特征的比较。花药四室,药室壁的发育属于"基本型",周原质团型绒毡层。小孢子母细胞连续型分裂。等四面体型四分体。二细胞成熟花粉,无孔沟。雌孢原多个,一般仅一个能继续发育。蓼型胚囊。助细胞具丝状器。反足细胞宿存。大孢子母细胞和合子具极性。宿存的一个助细胞具有吸器功能。细胞型胚乳,胚胎发育属于柳叶菜型的三叶变型。种皮源于外珠被,内表皮细胞壁螺旋状加厚。胚胎学特征表明,新木姜子属与木姜子属有密切的亲缘关系。较多的双胚囊异常现象,支持樟科与Monimiaceae具有紧密关系的推测。胚胎学特征不支持将无根藤属独立为科的观点。 相似文献
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Abstract. Gas exchange measurements were performed to test the hypothesis that failure of stomata to open in senescing leaves of Nicotiana glauca is caused by elevated concentrations of carbon dioxide in the intercellular spaces of leaf mesophyll tissue (ci ). Senescing leaves selected for experiments were completely chlorotic and lacked positive rates of photosynthesis. When stomata in detached epidermis from senescing leaves were illuminated in CO2-free air, they opened to similar apertures as those in detached epidermis from nonsenescing leaves. To compare the effects of changes in ci on stomatal responses of the two leaf types, leaf 'flags' of either nonsenescing or senescing leaves were illuminated at a photosynthetic photon flux density of 500 μmol m−2 s−1 in a gas exchange cuvette. Leaf temperatures were maintained at 23.5 ± 0.5°C, and vapour pressure differences between leaves and the air were maintained between 0.70 and 0.75kPa. Ci was adjusted by changing external concentrations of carbon dioxide in air circulating through the cuvette. Conductances and photosynthetic rates of nonsenescing leaves changed in response to changes in ci , but neither the conductances nor the photosynthetic rates of senescing leaves were affected significantly by changes in q. We conclude that guard cells of senescing leaves of Nicotiana glauca do not lose the capacity to respond to changes in carbon dioxide concentration and that increases in ci resulting from declining rates of mesophyll photosynthesis are not the sole cause of maintenance of stomatal closure during leaf senescence. The data suggest that factors external to guard cells may prevent them from responding to changes in carbon dioxide concentrations in intact senescing leaves. 相似文献
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Stable carbon isotopes as indicators of increased water use efficiency and productivity in white spruce (Picea glauca (Moench) Voss) seedlings 总被引:6,自引:1,他引:5
The relationship among water use efficiency (WUE), productivity and carbon isotopic composition (δ13C) in white spruce (Picea glauca (Moench) Voss) seedlings was investigated. Sixteen hundred seedlings representing 10 controlled crosses were planted in the field in individual buried sand-filled cylinders. The soil water content in the cylinders was measured using time domain reflectometry over two growing seasons and seedling water use determined by water balance. Two watering treatments were imposed: irrigation and dry land. There was significant (1.6–2.0%c) genetic variation in needle δ13C. Ranking of crosses in terms of δ13C was generally maintained over watering treatments and there was not a significant genetic versus environmental interaction. There was a positive correlation between δ13C and both intrinsic and long-term WUE (more positive δ13C with increased WUE) and between δ13C and productivity, suggesting a correlation due to variation in photosynthetic capacity. Root to shoot ratios did not increase in water-stressed plants, indicating that responses to drought were primarily at the level of gas exchange, rather than through morphological changes. Our results indicate that it should be possible to use δ13C as a surrogate for WUE and to select white spruce genotypes for high WUE without compromising yield. 相似文献
7.
Evalyne O.A.M. de Swart Arnold G. van der Valk Kenneth J. Koehler A. Barendregt 《植被学杂志》1994,5(4):541-552
Abstract. We estimated, using logistic regression techniques, the realized niches of the four dominant species in an experimental marsh complex located in the Delta Marsh, Manitoba, Canada. These models were then used to predict the probability of occurrence of these species in selected elevation ranges when water levels were raised in 1985 either 0, 30 or 60 cm above the long-term normal water level. These realized-niche models were calculated using elevation and species data collected in 1980. After having been eliminated by two years of deep flooding, the emergent vegetation in this complex had been re-established during a drawdown beginning in either 1983 or 1984. Our hypothesis was that from 1985 to 1989 the frequencies of occurrence of species in selected elevation ranges would converge to their probabilities predicted from the 1980 logistic models. This was not borne out by our results. Actual frequencies and predicted probabilities of occurrence of a species were similar at best less than 40% and then mostly in the control (0 cm) treatment. The realized-niche models were not adequate to predict the distribution of emergents after an increase in water level in the short term because the emergent species did not migrate upslope. Emergent species in the medium and high treatments either (1) died out - Scolochloa festucacea and Scirpus lacustris - after 3 yr because they could not survive permanent flooding, (2) stayed where they were - Phragmites australis - because they were unable to move upslope through clonal growth, or (3) became more widespread - Typha glauca only because of the expansion of small local populations already established in 1985 in areas dominated formerly by other species. 相似文献
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Storage proteins of interior spruce ( Picea glauca engelmanii complex) somatic embryos were compared to those of zygotic embryos by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. Somatic embryos contain the same storage proteins as zygotic embryos based on similarities of molecular weight, isoelectric variants, solubility characteristics and disulfide linkages. Storage protein levels varied among different somatic embryo genotypes; however, all genotypes tested accumulated significant amounts of storage proteins. Zygotic and somatic embryos display a similar developmental accumulation of storage proteins. The 22, 24, 33 and 35 kDa proteins appear in early stage embryos, while the 41 kDa protein begins to accumulate during mid cotyledon development. The 22, 24 and 41 kDa proteins accumulate continuously during cotyledon development in somatic embryos cultured on abscisic acid. In contrast, zygotic embryos display a more rapid and transient accumulation of these proteins. 相似文献
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专一转化人参二醇类皂苷Rb1为Rd的真菌菌株的筛选 总被引:2,自引:1,他引:2
于2009年的7-10月间在辽宁省的桓仁,吉林省的集安、靖宇、抚松等药材产区采集人参及人参根际土壤样品45份。通过真菌分离和培养,共获得真菌菌株105株,经形态学鉴定分属于15属48种。通过活性筛选,得到具有转化人参总皂苷活性的菌株25株,其中菌株SR87和SR105对人参皂苷Rb1具有专一转化活性。通过TLC和HPLC检测,其转化产物为人参皂苷Rd。经形态学鉴定,确定阳性菌株SR87为莫勒接霉Zygorhynchus moelleri,SR105为灰绿犁头霉Absidia glauca。这两株真菌均有较高的转化潜力,可以应用于制备人参皂苷Rd。 相似文献