基于支持向量机理论的植物根系图像边缘检测方法

由于传统边缘检测方法中存在噪声大、粗糙边缘和不准确边缘等缺点,因此在植物根系的研究中,采用传统的图像边缘检测方法检测出来的边缘信息都无法达到令人满意的效果.为此,基于支持向量机方法给出了一种改善的边缘检测算法.同时,提出了边缘检测算法流程,然后使用支持向量机分类方法对图像进行边缘检测;用所得到的边缘检测算法与Canny算法和Prewitt算法的性能进行了比较.仿真结果表明,给出的算法与Canny算法和Prewitt算相比,不仅边缘检测性能得到提高,而且可以一定程度地克服噪声干扰.     

枣棉间作系统枣树根系空间分布特征研究

[目的]对环塔里木盆地中心地带——阿克苏市的枣-棉花间作系统枣树吸收根根系空间分布特征进行研究,以期为枣-棉花间作系统枣树根系吸水运移模型的建立、枣树保护带宽度的确定及田间灌水、施肥技术的改进提供基础资料.[方法]采用根系分层挖掘法,挑拣每一个土层样方内的活根,清洁、阴干、分类、扫描,并用专业软件对根系长度等指标进行测定分析.[结果](1)垂直方向上,枣树吸收根根量主要集中在0～ 120 cm土层内,约占总量87.09;;(2)水平方向上,主要分布在距枣树树干0～150 cm范围内,占总量的83.67;;(3)根据棉花根系的分布,得到枣树与棉花根系分布密集区在距枣树100～150 cm、土层深度0～80cm的范围内.[结论]保护带的设置对于枣树根系的生长、缓解枣树与棉花间水分、养分的竞争有极其重要的作用,而保护带宽度的设定值得探讨,需要根据枣树的年龄、冠幅等进行综合判断.就此试验地的情况来看,在不改变该试验地枣树保护带宽度的条件下,枣树的施肥区域应在距枣树树干100～ 150 cm.     

人参不定根生物反应器培养及其动态学研究

利用5 L气球型气升式生物反应器研究蔗糖和氧化锗浓度对不定根生长和人参皂苷合成的影响,结果表明,当MS+IBA 5 mg/L培养基中加入蔗糖50 g/L时,每个反应器可收获不定根34.5 g(干重),皂苷生产量达到61.1 mg/L,显著好于蔗糖30和70 g/L处理;培养基中加入氧化锗30或60μmol时,促进不定根...     

稻水象甲幼虫危害根系对水稻生长及其产量的影响

稻水象甲对水稻的危害主要表现为成虫啃食稻叶、幼虫蛀食稻根,特别是幼虫破坏根系,直接影响水稻的生长发育和产量,对水稻生产危害极大。初步研究探讨了稻水象甲幼虫危害根系后对水稻的生长发育、经济性状和产量的影响。     

喀斯特地区植物根系对土壤元素迁移的影响

采用土柱淋滤试验,研究了乔木、灌木和草本的根系对土壤中钾、氮、钙元素迁移强度的影响.结果表明,不同植物根系对钾、氮、钙元素的迁移都有一定的活化效力,灌木与乔木的根系对钾、氮、钙元素迁移的活化效力比较接近,而草本的活化效力较弱;不同植被根系在土层(H)0≤H<10 cm中活化效力较弱,在土层10 cm≤H＜30 cm中活...     

玉米根系吸水细胞水平的杂种优势

在人工气候室水培条件下,以玉米(Zea mays L.)杂交种F₁代户单4号及其母本天四和父本478为材料,用细胞压力探针技术研究了正常供水和PEG-6000模拟–0.2 MPa水分胁迫条件下,玉米根皮层细胞水分关系参数的基因型差异。结果表明,根皮层细胞的直径、长度和体积均为F₁代>母本>父本;正常供水条件下3个玉米品种的根皮层细胞膨压均在0.6 MPa左右且品种间差异不显著,水分胁迫抑制了细胞的延伸生长且F₁代和母本的细胞膨压显著高于父本;根皮层细胞壁体积弹性模量均为父本>母本> F₁代,水分胁迫条件下的品种间差异显著;与正常供水条件相比,水分胁迫条件下细胞膨压显著降低,而弹性模量则大幅度提高;在两种水分条件下,水分跨细胞膜运转的半时间均为父本>母本>F₁代,且半时间在水分胁迫条件下均显著高于正常供水条件下;HgCl₂处理引起了半时间的延长,2-巯基乙醇则部分逆转了HgCl₂的效应;在两种水分条件下,根皮层细胞水导均为F₁代>母本>父本且品种间差异显著,水分胁迫则显著降低了细胞水导。试验证明杂交种F₁代的细胞水平根系吸水能力优于亲本,体现了杂种优势。     

泰山酸枣再生不定根特性的比较

[目的]为获得泰山酸枣高的不定根再生率。[方法]以泰山酸枣不定梢为外植体,以1／4MS为基本培养基,研究了生长调节剂浓度、不定梢切取的部位及培养方法等因素对不定根再生的影响。[结果]不定根诱导的最佳激素浓度为0．5mg／LIBA;切取带顶芽不定梢茎段利于进行不定根的再生;直接进行光培养比暗培养更有利于不定根的再生;在最适宜的不定根再生培养基上,不定根再生效果最好,再生率可达98．5％。[结论]该实验为酸枣组培快繁生产中高的移栽成活率奠定了基础。     

Spatial distribution characteristics of fine roots of Populus euphratica in a desert riparian forest

The soil-plant system is a very important subsystem of the soil-plant-atmosphere continuum (SPAC). The water uptake by plant roots is an important subject in the research on water transport in this SPAC and is also the most active study direction in the fields of ecology, hydrology and environment. The study of the spatial distribution pattern of fine roots of plants is the basis of constructing a water absorption model of plant roots. Our study on the spatial distribution pattern of fine roots of Populus euphratica in a desert riparian forest shows that the density distribution of its root lengths can be expressed horizontally as a parabola. The fine roots are concentrated within the range of 0–350 cm from the tree trunk and their amount accounts for 91.9% of the total root mass within the space of 0–500 cm. In the vertical direction, the density distribution of the fine root lengths shows a negative exponential relation with soil depth. The fine roots are concentrated in the 0–80 cm soil layer, accounting for 96.8% of the total root mass in the 0–140 cm soil layer. __________ Translated from Chinese Journal of Ecology, 2007, 26(1): 1–4 [译自: 生态学杂志]     

Hardware and software efficacy in assessment of fine root diameter distributions

Fine roots constitute the majority of root system surface area and thus most of the nutrient and water absorption surface. Fine roots are, however, the least understood of all plant roots. A sensitivity analysis of several software programs capable of providing root diameter distribution analyses was undertaken to determine if this software was capable of discriminating 10% changes in diameters of roots in the 0.05–0.2 mm diameter range. Digital images produced by drawing discrete lines, by scanning wires of various diameters, and by scanning roots from several legume species were analyzed and compared. None of the three packages were able to adequately analyze these images. Each introduced artifacts into the data that were severe enough to confound interpretation of the resulting diameter class length histograms at resolutions from 24 to 400 pixels (px) mm⁻¹, and root diameters from 0.06 to 0.5 mm or larger. One package was, however, clearly superior to the other two for routine digital analysis. All three packages require additional development before they are suitable for routine analysis of fine roots. Due to the 252 px mm⁻¹ resolution ceiling with currently available scanners, the smallest roots for which this level of discrimination is possible is 0.12 mm diameter. For many agricultural and forest species, up to 95% of their total root length is less than 0.1 mm in diameter. It is concluded that both hardware and software constraints currently inhibit the sensitivity of investigations into fine root diameter shifts in response to environmental conditions.     

胡杨根、茎、叶、愈伤组织总RNA提取的研究

胡杨根、茎、叶、愈伤组织等器官和组织的总RNA高质量提取是进行以胡杨RNA为基础的分子生物学研究的基础。以2 a生胡杨实生苗根系为材料,用CTAB-PVP提取缓冲液裂解细胞并变性蛋白,经氯仿/异戊醇(24∶1,v/v)抽提后,用3种不同的沉淀方法获得胡杨根系总RNA,电泳和定量测试等分析提取质量。结果表明,LiCl沉淀法结合70%乙醇洗涤沉淀两次获得的的胡杨根系总RNA,条带清晰、亮度高,且没有明显的DNA污染;actin基因片段设计引物对胡杨根系总RNA进行RT-PCR扩增,扩增片段与预期大小一致,表明该RNA可用于逆转录合成cDNA,提取物RNA中的Li 残留对逆转录酶活性的抑制作用不明显;该方法用以提取2 a生胡杨实生苗茎、叶及愈伤组织总RNA,均获得高质量总RNA。CTAB-PVP-LiCl(附70%乙醇洗涤RNA沉淀2次)的方法可用于胡杨根、茎、叶和愈伤组织总RNA的提取。