排序方式： 共有20条查询结果，搜索用时 15 毫秒
1.
为了提高肇实种植产量和质量，推动传统特色产业持续健康发展，结合肇实生产实际，在多年实践探索的基础上，从肇实生产栽培的地域环境、耕地条件和用种的选择到种子处理、催芽、播种及各生育期的田间管理、收获方法和病、虫、螺害防治等方面总结了肇实栽培技术。 相似文献
2.
3.
4.
5.
利用DNA标记(AFLP标记和SRAP标记)研究了11份芡、4份鸡王莲和1份克鲁兹王莲之间的亲缘关系,13对AFLP引物共产生490条条带,多态性条带447条(91.22%);9对SRAP引物共产生162条条带,多态性条带151条(93.21%);用UPGMA法建立的分子标记聚类树显示,克鲁兹王莲与其他材料(包括鸡王莲)差异很大,而鸡王莲与芡也有一定的差异。此外,对5份芡杂交材料的品质性状进行了检测,利用品质性状的数据进行聚类分析的结果表明,材料间的遗传距离很近,难以分辨相同种属不同材料的遗传关系和分类地位。 相似文献
6.
7.
为探究芡实种仁支链淀粉特性及淀粉分支酶基因（SBE）在支链淀粉合成过程中的作用,以芡实品种‘紫花苏芡’、‘紫花刺芡’为试材,分析种仁发育过程中支链淀粉含量、淀粉粒形成、淀粉糊化特性,并克隆‘紫花苏芡’淀粉分支酶基因（GeSBE1）cDNA全长。结果表明：‘紫花苏芡’种仁的支链淀粉含量及支链淀粉与直链淀粉含量的比值均高于‘紫花刺芡’;‘紫花苏芡’种仁的淀粉粒为不规则多面体、棱角明显、大小较均匀,‘紫花刺芡’种仁淀粉粒多数偏圆、棱角少、大小差异较大;‘紫花苏芡’种仁淀粉较‘紫花刺芡’糊化温度低。GeSBE1 cDNA全长2782 bp,开放阅读框为2466 bp,编码821个氨基酸;该基因的cDNA序列与莲藕SBEI基因的同源性高达78%;种仁发育过程中‘紫花苏芡’GeSBE1的表达量均高于‘紫花刺芡’,表明芡实GeSBE1可能与两品种支链淀粉含量的差异有关。 相似文献
8.
9.
A model of crop:weed competition, based on parameters from the logistic biomass growth of both crop and weeds in monocultures, was validated under several sets of conditions. Model inputs were (i) dry matter per unit area at 50% of seedling emergence ( Bi ) for each species; (ii) maximum total biomass of each species in monocultures ( K ); (iii) intrinsic growth rate of each species in monocultures ( r ); (iv) the accumulated thermal time required for each species to reach 50% emergence; and (v) the total accumulated thermal time during the growing season considered in the simulation. The model adequately described the dynamics of the competition between species when the relative yield total of the mixture was close to one, i.e. the slope and intercept of the regression between observed and simulated values was not significantly different from one and zero respectively. Sensitivity analysis indicated that final crop biomass was particularly affected by changes in the relative growth rate of the species. The occurrence of a critical period for weed control was explored using the model. The simplicity of the model validated here would allow its use as a tool to predict the outcome of competition and species relative importance, particularly when parameters needed to run more complex models are not available. 相似文献
10.
Martin R. Hughes Oliver E. Hooker Travis E. Van Leeuwen Alan Kettle‐White Alastair Thorne Paulo Prodhl Colin E. Adams 《Ecology of Freshwater Fish》2019,28(1):4-10
Large and long‐lived piscivorous brown trout, Salmo trutta, colloquially known as ferox trout, have been described from a number of oligotrophic lakes in Britain and Ireland. The “ferox” life history strategy is associated with accelerated growth following an ontogenetic switch to piscivory and extended longevity (up to 23 years in the UK). Thus, ferox trout often reach much larger sizes and older ages than sympatric lacustrine invertebrate‐feeding trout. Conventional models suggest that S. trutta adopting this life history strategy grow slowly before a size threshold is reached, after which, this gape‐limited predator undergoes a diet switch to a highly nutritional prey source (fish) resulting in a measurable growth acceleration. This conventional model of ferox trout growth was tested by comparing growth trajectories and age structures of ferox trout and sympatric invertebrate‐feeding trout in multiple lake systems in Scotland. In two of the three lakes examined, fish displaying alternative life history strategies, but living in sympatry, exhibited distinctly different growth trajectories. In the third lake, a similar pattern of growth was observed between trophic groups. Piscivorous trout were significantly older than sympatric invertebrate‐feeding trout at all sites, but ultimate body size was greater in only two of three sites. This study demonstrates that there are multiple ontogenetic growth pathways to achieving piscivory in S. trutta and that the adoption of a piscivorous diet may be a factor contributing to the extension of lifespan. 相似文献