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生物活性水对玉米种子萌发及幼苗生长的影响 总被引：1，自引：0，他引：1
以北农青贮308玉米种子为试验材料,分别用生物活性水稀释10、25、50、100、200、400、800、4000倍对玉米种子进行浸种处理,以蒸馏水为对照,比较种子的发芽率、发芽势、吸水值、贮藏物质转运率、生物量、根长、芽长、叶绿素含量。试验结果表明,除稀释10倍处理外,不同浓度生物活性水均能显著提高玉米种子的发芽率、发芽势及苗期的长势和叶绿素的含量,其中稀释100倍的生物活性水最有利于种子的萌发,稀释50倍的生物活性水在苗期对壮苗和促进株高效果最明显。 相似文献
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为探讨生物炭缓解铜胁迫对盘菜幼苗伤害的调节作用机制,以温州盘菜为试材,通过盆栽试验,研究了不同生物炭添加量(3%、5%)对铜胁迫(300mg·kg~(-1))下盘菜种子萌发、叶绿素相对含量(SPAD)、生长性状、活性氧清除系统酶活性、丙二醛含量的影响。结果表明:生物炭浸提液可以缓解由铜胁迫造成的盘菜种子萌发抑制;铜胁迫下盘菜幼苗生长缓慢,以及生长性状、叶绿素相对含量均有所降低,活性氧清除系统酶(SOD、POD)活性以及丙二醛(MDA)含量均呈增加趋势;随着生物炭添加量的增加,叶绿素相对含量呈上升趋势,活性氧清除系统酶(SOD、POD)活性以及丙二醛(MDA)含量均有一定程度的下降。综上可见,生物炭可以提高铜胁迫下盘菜苗期的抗氧化能力和对铜胁迫的耐受性,缓解铜污染对盘菜幼苗的伤害,利于调节盘菜幼苗的生理代谢。 相似文献
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在同一生境下用种子苗、根茎苗繁殖光果甘草（GlycyrrhizaglabraL．）、胀果甘草（GlycyrrhizainflataBat．）、乌拉尔甘草（GlycyrrhizauralensisFisch．）,并对其地上部分（株高）和地下部分（根数、根粗、根茎数和根茎粗）进行比较研究。结果表明：（1）5种甘草地上部分、地下部分生长特征大部分种子苗优于根茎苗。（2）j种甘草生长特性表现不一致。在株高方面,种子苗和根茎苗均为胀果甘草表现最优;在根数方面,种子苗和根茎苗均为乌拉尔甘草最优;在根茎数和根粗方面,种子苗为乌拉尔甘草最优,根茎苗为胀果甘草最优;在根茎粗方面,种子苗为乌拉尔甘草最优,根茎苗为胀果甘草最优。（3）3种甘草种子苗、根茎苗根粗和根茎粗均与株高呈相关关系。 相似文献
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A simulation model was used to study the interaction between landscape pattern and components of the dispersal strategy of the mistletoe Amyema preissii by mistletoe birds (Dicaeum hirundinaceum). The landscape was modelled as a map of host trees for the mistletoes, characterised by the total density and clumpiness of trees. A landscape was considered as a set of equal sized bird territories, with the majority of seeds produced in such a territory dispersed within that area. Age-specific birth and death rates of mistletoes were measured in the field. Seed dispersal was characterised by four parameters: the fraction of within-tree seed dispersal, the ratio of attractiveness to birds of tree canopy volume over attractiveness of mistletoe fruit number, seed survival, and the fraction of seeds leaving their original territory.A sensitivity analysis was carried out using a factorial design on landscape type and dispersal parameters. General linear modelling of mistletoe population size after 100 years showed that, in a given landscape, seed survival was the strongest determinant. Total mistletoe population also increased exponentially with tree density, but the number of mistletoes per tree decreased. Population size depended on tree clumping as well, with larger mistletoe populations sustained by woodlands with clumped trees.For a given level of seed survival, population size increased when birds were more attracted by canopy volume than by fruit crop. The strongest increase in population size occured for a combination of low tree density with high relative attractiveness. The relative effects of the fraction of within-tree dispersal and tree density depended on seed survival. For lower survival, fraction of within- tree dispersal determined population size more strongly while for higher survival, tree density became the dominant factor. Population size was negatively correlated with the fraction of within-tree dispersal. Finally, population size strongly increased only if dispersal out of a bird's territory represented 10% of the seed crop, a high value which seems unlikely in the field.The results support the hypothesis that woodland fragmentation promotes invasion by mistletoes. Although simulated mistletoe populations deviated from our natural population in having an excess of young individuals, sensitivity analysis produced several non- intuitive results and is thus valuable in focussing further efforts on field data collection. This study also illustrates how a simulation model of population dynamics can help in determining control strategies for an invasive organism. A reduction in seed survival and disinfection of larger trees would appear to be the most efficient strategy. 相似文献
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土壤有效硅对黄瓜种子萌发和幼苗生长代谢的影响 总被引：18，自引：0，他引：18
利用盆栽试验研究土壤有效硅对黄瓜种子萌发和幼苗生长代谢的影响。结果表明: 土壤有效硅含量在55. 1 ～202. 8 mg·kg-1范围内, 随含量的增高, 种子萌发过程中蛋白酶和脂肪酶活性升高, 呼吸速率加快, 种子活力升高, 萌发速度加快; 幼苗生长过程中光合强度增强, 根系活力、硝酸还原酶活力升高, 蒸腾强度减弱, 蒸腾比率和叶片含水量升高, 说明土壤中的硅被黄瓜有效利用; 土壤有效硅含量超过202. 8 mg·kg-1时, 其对黄瓜种子萌发和幼苗生长的促进作用不再显著增加。 相似文献
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In landscapes dominated by late-successional plant communities, early-successional species may lead a tenuous existence, persisting only as fugitives or relying on refuges in marginal habitats to provide a persistent seed source. The objective of this study was to relate fine-scale distributions of early-successional tree species in hemlock-hardwood forests of northern Wisconsin, USA to potential landscape persistence strategies. A special emphasis was placed on eastern white pine (Pinus strobus), a restoration priority in the region. Witness tree data from nineteenth century US Public Land Survey records (encompassing 40,610?km2 and 106,790 trees) were used with modern environmental data to relate species distributions to habitat characteristics. Early-successional tree species had strong positive associations with marginal habitats such as inclusions of sandy soil and margins of lakes, wetlands, and rivers. Marginal habitats occupied ~44 % of the landscape, which may help account for the abundance of early-successional species in our study area relative to other hemlock-hardwood forests. Populations of early-successional species in marginal habitats could also have provided important seed sources for the upland mesic landscape matrix, as >70 % of the landscape was within 200?m of these habitats. The degree to which early-successional species were limited to marginal habitats largely followed predictions based on species life-history characteristics, except that white pine was more common than expected in upland mesic habitats. These findings illustrate the potential importance of landscape heterogeneity for persistence of early-successional species in late-successional forest landscapes and provide baseline information on habitat associations and landscape dynamics that will be useful in restoration efforts. 相似文献
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Ecological phenomena vary over space and time and interpretation of these processes also varies depending on the measurement
scale. As the spatial scale of observation increases and decreases, changes in population abundance will likely exhibit alternating
patterns of asynchrony and synchrony. While the study of how and why population dynamics change with spatial scale of measurement
is intrinsically interesting, most population ecologists seek to study mechanisms of population change on a discrete study
area. Our study develops methods that population ecologists can use to determine spatially appropriate sampling designs, and
demonstrates how such spatial scales can be determined for 25 species of songbirds using long-term data from the boreal mixedwood
forest of Alberta, Canada. To determine minimum scales of synchrony in population dynamics, we calculated the average correlation
of changes in population abundance over time across different numbers of fixed-radius point-count samples. We then used a
randomization test to remove the effect of number of replicates from the determination of appropriate spatial scale. The maximum
extent of synchrony was estimated as the distance where population dynamics were no longer correlated. Estimates of the minimum
scale of synchrony differed between species, ranging from 3.1 to 18.6 ha. The maximum scale of synchrony was estimated to
be greater than or equal to 8 km for 14 of the 25 species examined, and to be greater than or equal to 70 km for Tennessee
Warbler (Vermivora peregrina). Maximum spatial extents were significantly correlated with body mass and territory size. 相似文献
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Seeds were collected from a range of citrus rootstock types in China and sent to Australia for evaluation. Before evaluation proceeded, however, the seeds and their seedlings were characterised for uniformity and trueness-to-type. The seeds were cultured in vitro and/or germinated in sand beds to assess whether or not they were mono- or polyembryonic. Seedlings were then rogued on the basis of vigour and morphology before isozyme profiles were developed from leaf extracts to assess seedling uniformity within introductions. Isozyme profiles were also compared to those of the source trees, as well as hybrids generated between some of them in China, to assess and verify trueness-to-type. The degree of variability between the seedlings propagated from the imported seeds and their source trees in China differed between accessions, which highlighted some of the issues that need to be considered when importing citrus germplasm as seeds. Regardless of whether the seedlings could be shown to be identical to their source tree in China, three uniform seedlings of polyembryonic types were established in arboreta as Australian source trees to provide propagules for evaluation and possibly commercial use. 相似文献
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‘玉山鱼榧’是从磐安县野生榧树古树中选育出的新品种,母树为实生起源古树,通过无性繁殖培育子代。该品种种实、种核比当前香榧主栽品种‘细榧’大,种核表面有2~6只榧眼,成熟期较迟。种实长倒卵状椭圆形,假种皮维管束直或扭曲,平均单个鲜质量10.8 g,纵径3.74 cm,横径2.28 cm,种形指数1.65,假种皮厚0.35 cm,鲜出核率36.39%,干出核率67.15%;种核平均单个鲜质量3.9 g,纵径3.37 cm,横径1.49 cm,核形指数2.28,壳厚0.08 cm,干核出仁率66.55%;种仁平均单个干质量1.6 g,脂肪含量48.6%,总糖含量0.83%,蛋白质含量18.02%,品质佳,商品性能优良。在浙江磐安开花期4月中旬,成熟期第二年9月中旬,种实发育期17个月,树势强,结果早,丰产,稳产,经济寿命长。幼苗和幼树喜阴湿,怕高温干旱和强日照,开始结实后又需要有充足的阳光,根系耐湿性差,怕积水。采用SSR分子标记对‘玉山鱼榧’的遗传鉴定表明,‘玉山鱼榧’与‘细榧’在DNA水平上存在明显的差别。‘玉山鱼榧’适宜在浙江省香榧产区栽培,其栽培技术要求与‘细榧’相同。 相似文献
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Monica G. Turner William H. Romme Rebecca A. Reed Gerald A. Tuskan 《Landscape Ecology》2003,18(2):127-140
Landscape patterns of quaking aspen (Populus tremuloides) seedling occurrence and abundance were studied after a rare recruitment event following the 1988 fires in Yellowstone National
Park, Wyoming, USA. Belt transects (1 to 17 km in length, 4 m width) along 18 foot trails were surveyed for aspen seedlings
on the subalpine plateau of the Park, along gradients of elevation and geologic substrate, during the summer of 1996. Aspen
seedling presence and density were characterized as a function of elevation, geologic substrate, slope, aspect, vegetation/cover
type, presence of burned forest, and distance to nearest adult aspen stand. Presence of aspen seedlings was best predicted
by the incidence of burned forest and proximity to adult aspen; aspen seedlings were only found in burned forest and were
more likely to occur closer to adult aspen clones. When tested against independent data collected in 1997, the logistic regression
model for aspen seedling presence performed well (overall accuracy = 73%, Taup = 0.41). When present, variation in aspen seedling density at local scales (≤ 200 m) was largely explained by elevation,
with higher densities observed at lower elevations. At broad scales (> 1 km), seedling density was a function of cover type,
elevation, aspect, slope, and burn severity, with greater seedling density in more severely burned forested habitats on southerly,
shallow slopes at lower elevations. Aspen seedling densities ranged from 0 to 46,000 seedlings/ha with a median density of
2,000/ha on sites where they occurred. Aspen seedlings were most abundant in the south central and southwest central regions
of the park, approximately an order of magnitude less abundant in the southeast region, and nearly absent in the north central
area. Establishment of new aspen stands on Yellowstone's subalpine plateau would represent a substantial change in the landscape.
However, the long-term fate of these postfire aspen seedlings is not known.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Tree size distributions are the outcome of demographic processes and disturbance events, and size distribution analysis provides a useful tool for understanding pattern and process in tree population dynamics. Demographic bottleneck mechanisms such as fire “traps” are important for driving tree cover dynamics in savanna systems, and bottlenecks might be expected to be revealed by bimodal size distributions in savanna tree communities. We tested the relative fit of monotonic and bimodal Weibull distributions to tree height distributions across 36 0.1-ha plots over 4 years in Serengeti National Park, Tanzania, using a Bayesian analysis. The plots were subjected to two fire treatments and spanned a mean annual rainfall gradient ranging from 600 to 900 mm year?1. We found that Serengeti trees are highly bimodal in their height distributions, with a pronounced gap in the 1–3 m height range, suggesting that demographic bottlenecks are a pervasive feature of this system. We also found that pre- and post-bottleneck tree densities are increasing and declining over time, respectively. Pre-bottleneck density declined with fire and increased with mean annual precipitation, and exhibited a rainfall by fire interaction, with negative fire effects becoming more important at the wet extreme of our rainfall gradient. Overall, despite the negative effect of fire on pre-bottleneck trees, the density of the latter is increasing over time, suggesting that although recruitment into larger size classes has been tightly constrained in the past, there is mixed support for a role of fire in maintaining this pattern under current burning regimes. 相似文献
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种子处理对西瓜细菌性果斑病的防治效果 总被引：1，自引：0，他引：1
利用干燥与药剂相结合、引发与药剂相结合的种子采后处理方法对西瓜种子的除菌效果进行了研究。应用PCR方法检测未经人工接种的西瓜种子,幼苗生长方法检测人工接种和自然带菌(Ac)的西瓜种子,结果表明,未经人工接种的西瓜种子中,从没有发酵经室内阴干4h后热风烘干、以及不管是否发酵室内阴干的种子上均检测到Ac菌的特异性条带。人工接种Ac菌的西瓜种子随着室内阴干时间的延长,幼苗细菌性果斑病(BFB)的发病率呈上升的趋势,由阴干3h的0.9%上升到阴干6h的20.4%。同时随着阴干时间的延长,种子的成苗率降低,由阴干3h的52.6%下降到阴干6h的23.9%。说明快速干燥能有效控制带菌种子幼苗BFB的发生,提高种子的健康质量。不同杀菌剂对自然带菌(Ac)西瓜种子杀菌效果的研究结果表明,不管是药剂处理种子还是含药的固体基质引发处理种子,其种子质量都没有显著的差别。药剂处理的种子平均每株幼苗的鲜质量均高于含药的固体基质引发处理的种子幼苗的鲜质量。通过幼苗生长鉴定,含药固体基质引发处理的相对防治效果在57.1%～78.6%之间,而药剂处理的相对防治效果在84.6%～100.0%之间。含药的固体基质引发处理对降低幼苗BFB发病率的效果要差。 相似文献
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The vegetative and reproductive performances of ‘Coscia’ pear (Pyrus communis L.) grown on nine rootstocks [OHF 69, OHF 97, OHF 217, OHF 333, OHF 513 and BP 1 (P. communis), clonal seedling (Davis AxB) of Pyrus betulifolia and quince BA 29 and EMA (Cydonia oblonga)] were compared during a 9-year period. The trial was conducted at the Experimental Station ‘Avnei Eitan’ in northern Israel (elevation 400 m above sea level, a.s.l.), on a well-drained soil with pH 7.1. Trees were planted in December 1998, spaced at 4.0 m × 2.0 m and trained with a central axis. The most vigorous trees were on P. betulifolia seedlings, followed by the four OHF rootstock (69, 97, 333, 513) and BP 1 (with no significant difference between them). All the above rootstocks demonstrated greater vigor than OHF 217 and quince BA 29 or EMA. The highest cumulative yields per tree were harvested from trees on the four OHF rootstocks (69, 97, 333, 513) and P. betulifolia followed by the BP 1. The two quince rootstocks, as well as OHF 217, had the lowest cumulative yield and the lowest yield of large fruit. A positive correlation was found between the vigor of the tree, as affected by the rootstock, and both the total yield and the fruit size. We conclude that in a warm climate, yield efficiency is not the only parameter that should be taken into account, and building a strong tree for a weak cultivar is the first requirement for establishing an orchard. 相似文献
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为了明确排种量对甘薯采苗量和薯苗质量的影响,以商薯19(S19)和烟薯25(Y25)为试验材料,采用平排的方式,设置10、15、20、25 kg/m2 4个排种量,其中25 kg/m2为常规排种量,从采苗量、薯苗质量、薯苗生长特性和薯苗群内环境条件(温湿度和光照强度)等方面进行分析。结果表明：S19和Y25的采苗量均随排种量的增加表现先升高后降低的趋势,以20 kg/m2排种量处理最高,分别为2 124株/m2和986株/m2,较10、15、25 kg/m2处理分别显著增加107.4%、19.1%、10.1%和100.4%、45.4%、8.6%;Y25叶片净光合速率、茎部剪切力和拉伸力也均以20 kg/m2排种量处理最高,分别较25 kg/m2排种量处理显著增加16.54%、25.4%、44.5%;S19和Y25薯苗壮弱比、茎部机械力、茎部木质素含量及叶片、叶柄和茎干率也都是20 kg/m2... 相似文献