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Xiangwen Fang Youbin Li Danghui Xu Xiaoming Yang Gang Wang 《Trees - Structure and Function》2007,21(1):93-100
In many resprouting plants, carbohydrates are stored as starch in roots and will be mobilized to support above-ground tissue
regrowth after shoot damage. Our objective was to determine how activities of starch hydrolytic enzymes change damage-induced
starch mobilization in Caragana korshinskii roots after above-ground tissue loss. Zero percent (control), 30% (30% RSL), 60% (60% RSL) of main shoot length, and 25%
(25% RSN), 50% (50% RSN), and 100% (100% RSN) of main shoot number were removed. Compared with control plants, clipping accelerated
the reduction of starch in the roots, increased sucrose flux per flower per hour and nectar production per flower per day
in 30% RSL, 60% RSL, 25% RSN, and 50% RSN treatments, and improved vegetative growth in 100% RSN treatment. All treatments
had similar total nonstructural carbohydrate (TNC) concentrations in leaves, shoots, and stems with the exception of 100%
RSN with higher TNC concentration in shoots. Both α-, and β-amylase activities were enhanced by clipping, the former being
more strongly correlated with starch degradation in the roots than the latter. The other two possible starch-breaking enzymes,
α-glucosidase, and starch phosphorylase showed no significant differences in the activities between treatments. The results
suggest that starch degradation in the roots of C. korshinskii was regulated by α-amylase activity and more mobilized starch was used to support vegetative growth in 100% RSN treatment
and support sexual reproduction followed by other clipping treatments. 相似文献
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Abstract. The annual cycle of vegetative growth in the Mediterranean shrub Halimium halimifolium (Cistaceae) subjected to simulated and natural browsing on the stabilized sands of Doñana National Park (SW Spain) is described. In a drier area without herbivory (Monte Intermedio) plants were subjected to different intensities of clipping. In a more humid area with high herbivory pressure (Monte Negro) plants were isolated by cages. Plants were monitored monthly from February to November 1994. Vegetative growth starts in March and ends in June or July, according to temperature and water availability. Plants intensely clipped and plants subjected to natural browsing responded maximally regarding shoot length, and number of leaves on main shoots and branches. Clipped plants, however, did not reach the height and cover of controls. 相似文献
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柠条(Caragana korshinskii)在地上组织破坏后进行补偿性生长,这是重复利用柠条资源的基础,但对 柠条不同刈割方式下营养生长补偿的模式有待探讨。该文通过5种刈割方式:去除主枝长的30%(30%RSL) 、去除主枝长的60%(60%RSL)、去除分枝数的25%(25%RSN)、去除分枝数的50%(50%RSN)和去除分枝 数的100%(100%RSN)来研究柠条的营养生长补偿。结果表明:刈割处理的柠条生物量当年发生了超补偿 ,当年生枝数/枝、当年生枝长、当年生枝生物量/枝、当年生枝生物量/株比对照高。对照、30%RSL和 60%RSL 处理未长出基梢。 100%RSN处理的基梢数/刈割枝、基梢长、单个基梢平均生物量显著高于25%RSN 和50%RSN处理,基梢生物量/株随刈割去除生物量的增加而增加。100%RSN 处理未结果,其它处理果实产量 表现出超补偿或精确补偿。对照处理营养生长和生殖生长均低,其它处理当年生枝生物量与果实产量成显 著负相关。从整个生长季节来看,营养生长主要集中在果实成熟之前。我们认为,100%RSN处理是柠条地上 组织破坏后尽快恢复的合理方式,其当年生生物量远高于其它处理。顶端优势的破坏促使休眠芽的萌发, 根冠比的改变使地上组织获得较多养分和水分,根系储存的碳水化合物的供应是促使刈割柠条营养生长超 补偿的的可能机制,而减少生殖生长对资源的消耗,是100%RSN处理地上生物量尽快恢复的另一重要因素 。 相似文献
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Abstract. Grassland communities are increasingly recognized as disturbance‐dependent ecosystems, yet there are few replicated, multi‐site studies documenting vegetation responses to varying frequencies and types of grassland disturbance. Even so, land managers frequently manipulate disturbance regimes in an attempt to favour native grassland plants over exotic species. We conducted a factorial experiment testing three frequencies of clipping combined with litter accumulation, litter removal, and soil disturbance within the highly threatened California coastal prairie plant community. We monitored the response of native/exotic, grass/forb plant guilds once a year for four years. More frequent clipping reduced cover of exotic grasses and favoured exotic forbs, whereas native species were largely unaffected by clipping frequency. Litter accumulation, litter removal, and soil disturbance did not affect vegetation composition. Effects of litter accumulation may take longer than our experiment allowed, and soil disturbance due to our treatments was not sufficiently strong to show consistent effects relative to mammalian soil disturbance. Treatment response of some plant guilds differed among sites, highlighting the importance of replicating experiments at several sites before recommending conservation management practices. 相似文献
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Question: Which is the response of the evergreen Quercus ilex and the deciduous Q. cerrioides to repeated disturbances? Location: central Catalonia (northeastern Spain), in the areas affected by two of the largest historically recorded wildfires in NE Spain: the Bages‐Berguedà fire (24 300 ha forested area burned in July 1994), and the Solsonès fire (14 300 ha burned in 1998). Methods: Survival and growth of individuals of Quercus ilex and Q. cerrioides were evaluated in plants subjected to different fire histories and experimental disturbances (burning, cutting or clipping) applied either before or after summer. Results: Survival was high (> 99%), with both species showing a similar high resistance to disturbances. Growth after experimental disturbance was positively related to the size of the individual before the latest forest fire occurred. Fire history had a large effect on resprout growth, as the repeated incidence of disturbances lowered the capacity of individuals to grow. The type and season of experimental disturbance experienced by plants had a large effect. Individuals that experienced total above‐ground loss had lower growth rates than those with partial loss. A similar pattern was observed in individuals disturbed after the summer in relation to those disturbed before summer. Conclusions: The larger growth rates recorded in Q. cerrioides across all fire histories and experimental treatments, and the higher vulnerability of Q. ilex to increased fire frequency, intensity of experimental disturbance, and disturbance season, provide evidence for the relatively high susceptibility of the latter to repeated disturbances. This view disagrees with the larger resilience of this species compared to co‐existing deciduous oaks, as reported. 相似文献
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Are clonal plants more tolerant to grazing than co-occurring non-clonal plants in inland dunes? 总被引:4,自引:0,他引:4
Clonal traits such as clonal integration and storage functions of rhizomes or stolons may provide clonal plants with additional
advantages against grazing over non-clonal plants. Here, we hypothesize that clonal species have a larger capacity for compensatory
growth than co-occurring non-clonal species. In inland dunes in northern China, individual plants of two rhizomatous clonal
species (Bromus ircutensis and Psammochloa villosa) and two non-clonal ones (Artemisia intramongolica and Astragalus melilotoides) were subjected to 0% (control), 50% (moderate) and 90% (heavy) shoot removal. Compared with control, heavy clipping greatly
increased the relative growth rate in Bromus and Psammochloa, but decreased that in Artemisia and Astragalus. Heavy clipping affected above-ground dry weight and the number of modules more negatively in Artemisia and Astragalus than in Bromus and Psammochloa. These results support the hypothesis and suggest that clonal species are more tolerant to grazing than co-occurring non-clonal
species in inland dunes. 相似文献
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