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971.
废橡胶颗粒浸提液物质释放及其浸种对草坪植物生长的影响 总被引:3,自引:0,他引:3
纯胶粒浸提液、胶粒与壤土混合的浸提液中重金属含量分析表明,纯胶粒浸提液中Zn含量最高,其次为Pb,而Cd与Cu最少;与纯胶粒浸提液相比,胶粒与壤土混合的浸提液中Zn含量显著降低.紫外吸收光谱图显示,胶粒粒径越小,浸提液中有机物越复杂.用4种不同粒径胶粒的浸提液对2种草坪植物种子浸种处理后进行培养,研究了草坪植物的生长效应.结果表明,胶粒浸提液浸种对2种草坪植物的种子萌发率影响不大,但对株高产生不同的影响.对黑麦草而言,以2~4 mm胶粒浸提液浸种的株高为最高,1~2和4~6 mm胶粒浸提液浸种株高与之差异较大,分别降低1.52和1.32 cm,但均与对照无显著差异.对于高羊茅,以粒径1~2 mm胶粒浸提液浸种的株高为最低,比对照降低了18.76%,其它处理间无明显差异.浸提液浸种对黑麦草地下生物量有明显的抑制作用,但对根长生长有促进作用.胶粒浸提液浸种对2种草坪植物的地上生物量无明显影响.从胶粒浸提液的物质释放及其浸种对草坪植物生长的影响来看,废胶粒可用于运动场草坪的基质组配. 相似文献
972.
973.
974.
桂西南石漠化山地土壤种子库的基本特征及植被恢复对策 总被引:3,自引:0,他引:3
采用幼苗萌发法对广西平果县龙何示范区石漠化山地的土壤种子库进行初步研究。结果表明,该地区土壤种子库共有108种植物,隶属于33科81属,其中草本81种、灌木20种、藤本7种;其土壤种子库的种子密度为64.6~339.7粒.m-2,且在不同土地利用类型区及不同季节存在较大差别。在分析土壤种子库对其植被恢复作用的基础上,认为可采取自然封育和人工造林等措施,以促进现存植被的正向演替。 相似文献
975.
目的:测定掌握莱芜灰树花野生菌株的生物学特性,为其开发利用提供科学依据。方法:采用组织分离法和菌丝尖端纯化技术分离纯化菌种;采用生长速率法测定其生长适宜条件。结果:该野生菌株的菌丝体生长的最适温度为28℃;最适pH值为5.5;在被测的11种碳源和7种氮源中,最佳碳源为甘露糖,最佳氮源为(NH4)2SO4;KH2PO4对菌丝体的生长具有明显的促进作用,促进效果达223.64%;培养料最适含水量为65%;子实体生长发育温度24~30℃,平均转化率为66.37%。结论:莱芜灰树花野生菌株为转化率中等的高温型株系。 相似文献
976.
The exact identification of individual seed sources through genetic analysis of seed tissue of maternal origin has recently brought the full analytical potential of parentage analysis to the study of seed dispersal. No specific statistical methodology has been described so far, however, for estimation of the dispersal kernel function from categorical maternity assignment. In this study, we introduce a maximum-likelihood procedure to estimate the seed dispersal kernel from exact identification of seed sources. Using numerical simulations, we show that the proposed method, unlike other approaches, is independent of seed fecundity variation, yielding accurate estimates of the shape and range of the seed dispersal kernel under varied sampling and dispersal conditions. We also demonstrate how an obvious estimator of the dispersal kernel, the maximum-likelihood fit of the observed distribution of dispersal distances to seed traps, can be strongly biased due to the spatial arrangement of seed traps relative to source plants. Finally, we illustrate the use of the proposed method with a previously published empirical example for the animal-dispersed tree species Prunus mahaleb. 相似文献
977.
978.
The molecular mechanisms underlying complex social behaviours such as dominance are largely unknown. Studying the cooperatively breeding African cichlid Neolamprologus pulcher, we show that dominant females were similar to dominant males in dominance behaviour, high testosterone levels and brain arginine vasotocin expression (a neuropeptide involved in vertebrate territorial, reproductive and social behaviours) compared to subordinate helpers, but had lower levels of 11-ketotestosterone than males. Furthermore, brain gene expression profiles of dominant females were most similar to those of the males (independent of social rank). Dominant breeder females are masculinized at the molecular and hormonal level while being at the same time reproductively competent, suggesting a modular organization of molecular and endocrine functions, allowing for sex-specific regulation. 相似文献
979.
Minimal model of self-replicating nanocells: a physically embodied information-free scenario 总被引:1,自引:0,他引:1
Fellermann H Solé RV 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2007,362(1486):1803-1811
The building of minimal self-reproducing systems with a physical embodiment (generically called protocells) is a great challenge, with implications for both theory and applied sciences. Although the classical view of a living protocell assumes that it includes information-carrying molecules as an essential ingredient, a dividing cell-like structure can be built from a metabolism-container coupled system only. An example of such a system, modelled with dissipative particle dynamics, is presented here. This article demonstrates how a simple coupling between a precursor molecule and surfactant molecules forming micelles can experience a growth-division cycle in a predictable manner, and analyses the influence of crucial parameters on this replication cycle. Implications of these results for origins of cellular life and living technology are outlined. 相似文献
980.
Rolletschek H Nguyen TH Häusler RE Rutten T Göbel C Feussner I Radchuk R Tewes A Claus B Klukas C Linemann U Weber H Wobus U Borisjuk L 《The Plant journal : for cell and molecular biology》2007,51(3):468-484
The glucose-6-phosphate/phosphate translocator (GPT) acts as an importer of carbon into the plastid. Despite the potential importance of GPT for storage in crop seeds, its regulatory role in biosynthetic pathways that are active during seed development is poorly understood. We have isolated GPT1 from Vicia narbonensis and studied its role in seed development using a transgenic approach based on the seed-specific legumin promoter LeB4. GPT1 is highly expressed in vegetative sink tissues, flowers and young seeds. In the embryo, localized upregulation of GPT1 at the onset of storage coincides with the onset of starch accumulation. Embryos of transgenic plants expressing antisense GPT1 showed a significant reduction (up to 55%) in the specific transport rate of glucose-6-phosphate as determined using proteoliposomes prepared from embryos. Furthermore, amyloplasts developed later and were smaller in size, while the expression of genes encoding plastid-specific translocators and proteins involved in starch biosynthesis was decreased. Metabolite analysis and stable isotope labelling demonstrated that starch biosynthesis was also reduced, although storage protein biosynthesis increased. This metabolic shift was characterized by upregulation of genes related to nitrogen uptake and protein storage, morphological variation of the protein-storing vacuoles, and a crude protein content of mature seeds of transgenics that was up to 30% higher than in wild-type. These findings provide evidence that (1) the prevailing level of GPT1 abundance/activity is rate-limiting for the synthesis of starch in developing seeds, (2) GPT1 exerts a controlling function on assimilate partitioning into storage protein, and (3) GPT1 is essential for the differentiation of embryonic plastids and seed maturation. 相似文献