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排序方式: 共有196条查询结果,搜索用时 15 毫秒
1.
Summary Fruit of the blackberry, Rubus pennsylvanicus Poir. (Rosaceae), were examined to determine variation in maturation characteristics. Maturation timing and rate varied greatly among individual fruits, resulting in a bi-colored fruiting display comprised largely of two maturation stages, pre-ripe (salmon and scarlet) and ripe (dark brown and black). While ripe fruit were generally larger and heavier than pre-ripe fruit, exhibiting greater fresh and dry fruit weight, diameter, water content, and total seed weight, no significant differences were found in energy content, i.e. numbers of calories per gram pulp, or in pulp:seed ratio. The differences between ripe and pre-ripe fruit appear to be due largely to an increase in water content and seed weight with maturity. The fact that little energetic benefit accrues to the preferential selection of ripe fruit suggests that bi-colored Rubus displays may be considered to be unicolored. 相似文献
2.
Summary The idea of trade-offs among antiherbivore defences in plants is examined using data from a South American blackberry (Rubus bogotensis). Two distinct morphs of R. bogotensis, one with glandular trichomes and one without, were compared with respect to leaf toughness, number of prickles and prickle length. The two morphs were sympatric and grew under similar environmental conditions. The morph lacking trichomes had significantly tougher leaves and also tended to have more and longer prickles. Bioassay showed that Ithomiid larvae fed to a lesser extent on tough leaves than on more tender ones. Correlations between antiherbivore defences within each phenotype revealed three significant or almost significant negative relationships. The comparisons support the hypothesis that trade-offs exist among antiherbivore defences. 相似文献
3.
本文报告采自四川西部九寨沟自然保护区菰帽悬钩子(Rubus pileatus Focke)上的一个锈菌新种。标本上仅见冬孢子堆,冬孢子双胞,类似柄锈菌的冬孢子。由于未见性子器,属的地位尚难确定。然而,此菌的冬孢子堆外观酷似悬钩子植物上特有的单种属阿氏锈菌属(Arthuriomyces)。镜下观察测得孢子大小为40-55(-65) × 22-28 μm,孢壁厚度为3-4.5 μm,有细皱纹,每个细胞各具一芽孔。从芽孔数及位置看符合阿氏锈菌属的特征,因而将此菌暂隶于此属,命名为悬钩子生阿氏锈菌(Arthuriomyces rubicola sp. nov.) 相似文献
4.
Wajirou Suzuki 《Ecological Research》1993,8(1):107-110
Seeds of twoRubus species,R. palmatus var.coptophyllus andR. microphyllus, buried for 7.5 years in soil were subjected to germination tests to investigate their germinability and germination traits.
Most of the retrieved seeds were viable, and germinated at the alternating temperatures of 20/30°C in both light and dark.
The twoRubus species showed similar responses of germination to temperature and light, although the final percentages of germination were
slightly higher inR. palmatus var.coptophyllus. These characteristics of seed dormancy and germination would be involved in the species' utilization of ephemeral habitats
created by unpredictable and infrequent disturbances. 相似文献
5.
6.
高粱泡的生长调控与结实状况 总被引:3,自引:0,他引:3
高粱泡(Rubus lambertionus Ser.)是一种有利用价值的野生果树资源。其优点为:(1)结果早,产量高,亩产量可达500kg以上;(2)适应性广,耐瘠薄,是开发利用低山丘陵的优良资源植物;(3)果实营养丰富,酸味纯正,尤其是所含红色素稳定性好,是加工果汁饮料的优质添加剂;(4)果实采收期在11月中旬到12月底,此时气温低,有利于浆果加工和贮藏,并可利用农闲季节的劳动力。上述特点表明,高粱泡有很好的开发利用前景。但本种在野生状态下蔓生性强,多刺,并具有枝顶生根的习性,因而树形紊乱而松散,栽培时搭架困难,植株占地面积大,而单位面积产量不易提高。为了便于操作管理和提高产量,减少栽培成本,增进经济效益,我们于1990~1991年进行了生长和株形调控试验, 相似文献
7.
不同品种黑莓鲜果营养成分的比较 总被引:15,自引:4,他引:15
对5个黑莓(Rubusspp.)新品种鲜果的营养成分进行了比较分析。结果显示,5个品种黑莓鲜果的糖酸比较低,为3.11~6.18,风味偏酸。VC含量较高,达0.064~0.566 mg.g-1;VE含量为0.013~0.049 mg.g-1,品种间差异较大,以品种‘Triple Crown’的VE含量最高。矿质元素含量较高,其中品种‘Boysen’的Se含量最高,是其他品种的6~13倍;品种‘Young’的K、Ca、Zn和Fe含量都较高。黑莓鲜果含有8种人体必需氨基酸,不同品种黑莓鲜果的总氨基酸含量差异较大,其中品种‘Brazos’的总氨基酸含量最高,可达15.21 mg.g-1。 相似文献
8.
Mary Heskel Heather Greaves Ari Kornfeld Laura Gough Owen K. Atkin Matthew H. Turnbull Gaius Shaver Kevin L. Griffin 《Ecology and evolution》2013,3(5):1149-1162
Direct and indirect effects of warming are increasingly modifying the carbon-rich vegetation and soils of the Arctic tundra, with important implications for the terrestrial carbon cycle. Understanding the biological and environmental influences on the processes that regulate foliar carbon cycling in tundra species is essential for predicting the future terrestrial carbon balance in this region. To determine the effect of climate change impacts on gas exchange in tundra, we quantified foliar photosynthesis (Anet), respiration in the dark and light (RD and RL, determined using the Kok method), photorespiration (PR), carbon gain efficiency (CGE, the ratio of photosynthetic CO2 uptake to total CO2 exchange of photosynthesis, PR, and respiration), and leaf traits of three dominant species – Betula nana, a woody shrub; Eriophorum vaginatum, a graminoid; and Rubus chamaemorus, a forb – grown under long-term warming and fertilization treatments since 1989 at Toolik Lake, Alaska. Under warming, B. nana exhibited the highest rates of Anet and strongest light inhibition of respiration, increasing CGE nearly 50% compared with leaves grown in ambient conditions, which corresponded to a 52% increase in relative abundance. Gas exchange did not shift under fertilization in B. nana despite increases in leaf N and P and near-complete dominance at the community scale, suggesting a morphological rather than physiological response. Rubus chamaemorus, exhibited minimal shifts in foliar gas exchange, and responded similarly to B. nana under treatment conditions. By contrast, E. vaginatum, did not significantly alter its gas exchange physiology under treatments and exhibited dramatic decreases in relative cover (warming: −19.7%; fertilization: −79.7%; warming with fertilization: −91.1%). Our findings suggest a foliar physiological advantage in the woody shrub B. nana that is further mediated by warming and increased soil nutrient availability, which may facilitate shrub expansion and in turn alter the terrestrial carbon cycle in future tundra environments. 相似文献
9.
Expression of cucumber lipid-body lipoxygenase in transgenic tobacco: lipid-body lipoxygenase is correctly targeted to seed lipid bodies 总被引:2,自引:0,他引:2
A particular isoform of lipoxygenase (LOX, EC 1.13.11.12) localized on lipid bodies has been shown by earlier investigations
to play a role during seed germination in initiating the mobilization of triacylglycerols. On lipid bodies of germinating
cucumber (Cucumis sativus L.) seedlings, the modification of linoleoyl moieties by this LOX precedes the hydrolysis of the ester bonds. We analyzed
the expression and intracellular location of this particular LOX form in leaves and seeds of tobacco (Nicotiana tabacum L.) transformed with one construct coding for cucumber lipid-body LOX and one construct coding for cucumber LOX fused with
a hemagglutinin epitope. In both tissues, the amount of lipid-body LOX was clearly detectable. Biochemical analysis revealed
that in mature seeds the foreign LOX was targeted to lipid bodies, and the preferred location of the LOX on lipid bodies was
verified by immunofluorescence microscopy. Cells of the endosperm and of the embryo exhibited fluorescence based on the immunodecoration
of LOX protein whereas very weak fluorescent label was visible in seeds of untransformed control plants. Further cytochemical
analysis of transformed plants showed that the LOX protein accumulated in the cytoplasm when green leaves lacking lipid bodies
were analyzed. Increased LOX activity was shown in young leaves of transformed plants by an increase in the amounts of endogenous
(2E)-hexenal and jasmonic acid.
Received: 9 August 1999 / Accepted: 28 September 1999 相似文献
10.