基于边缘检测和区域定位的玉米根茎导航线提取方法

基于玉米根茎图像信息，提出一种基于边缘检测和区域定位的玉米根茎导航线提取方法。首先，利用最大类间方差法自动分割2G-R-B灰度图像，得到二值化图像，结合形态学处理、位置/面积去噪方法提高二值化图像质量，对去噪图像按列累加得到列像素累加曲线；针对传统方法得到的特征点中伪特征点较多的问题，引入高斯滤波器平滑累加曲线，并运用极值法减少玉米根茎伪特征点的干扰，在提取玉米茎秆边缘直线时，提出基于最远茎秆成像宽度的双侧边缘判别思路，通过扫描每条边缘直线的四边形封闭邻域有效剔除伪边缘直线；最后，根据边缘直线二次定位玉米的根茎区域范围，并剔除伪特征点，采用最小二乘线性拟合方法准确提取导航线。试验表明，本文算法处理一幅1280像素×720像素图像耗时约236ms，特征点拟合准确率为92%。与传统方法相比，本文算法精度高、实时性好，在缺苗、杂草较多和株距不标准的情况下仍具有较强的鲁棒性。     

湖南野生兰花的调查研究 Ⅱ.野生春兰茎的生物学特性

在对野生兰花形态特征观测的基础上，进一步探讨了不同根茎和假鳞茎的产生和生长发育的特点，根茎与假鳞茎的关系及有关的规律。     

角竹埋鞭苗造林的研究

角竹埋鞭苗造林与通常的母竹移植造林比较,其造林成活率无显著差异,但造林后二、三年内竹笋株数增加11％,竹笋产量增加8％,鞭梢年生长量增加15％,新竹的胸径无显著差异,埋鞭苗造林优于母竹造林。     

Effect of method of Imperata cylindrica management on maize grain yield in the derived savanna of south-western Nigeria

Field studies were conducted in 1991 and 1992 on a sandy loam soil in the derived savanna zone of south-western Nigeria to assess the effect of the underground organs of Imperata cylindrica (L.) Raeuschel on maize grain yield. Total dry matter of I. cylindrica in abandoned arable land averaged 16 t ha⁻¹ and rhizomes contributed 56% of this. Rhizome removal from soil before planting maize significantly increased maize yield relative to hoe tillage or slashing of I. cylindrica shoots before planting maize. Digging up rhizomes before planting maize and weeding the crop twice gave a yield reduction of only 23% compared with weed-free crops with rhizomes removed. Grain yield reduction was 51% in plots where rhizomes were only fragmented by hoe tillage and the crop was weeded twice. Grain yield was 62% less when maize was grown in slashed plots with intact rhizomes that were weeded four times (farmers' practice). Slashing without additional weeding resulted in crop failure in maize.     

Vegetative propagation of Solidago canadensis – do fragment size and burial depth matter?

Clonal species may benefit from human disturbance because their vegetative fragments may be distributed via soil. Solidago canadensis is an invasive rhizomatous perennial frequently found in ruderal environments. When creating new infrastructure, digging and cutting are two main factors that may influence the spread of S. canadensis into new areas. To have a better understanding of the invasive potential of S. canadensis, we investigated whether S. canadensis was able to survive and grow from stem cuttings as well as from rhizomes. Rhizomes and cuttings were collected from three populations in Eastern Norway. The rhizomes and cuttings were planted in a pot experiment to assess their vegetative ability to propagate. Rhizome fragments (5 and 10 cm long) were buried at 0.5, 10 and 30 cm depths. The cuttings were planted as 15 cm stems, with the bottom 5 cm pushed into the soil. The results showed that rhizome length did not have an effect on survival. Although some sprouting occurred at all burial depths, increasing depth had a negative effect on rhizome survival. In general, development of the cuttings was good, but there were differences between population performance and survival. These results imply that care must be taken when (i) constructing new sites, because digging and transport of soil masses may spread S. canadensis into new areas by rhizomes or cuttings, and (ii) mowing road verges and other ruderal areas to prevent the spread of stem cuttings from one area to another.     

Delayed harvest of reed canary grass translocates more nutrients in rhizomes

Abstract

Two field experiments, one in large plots and the other in small framed plots, were conducted in Umeå, northern Sweden. The objectives were (1) to examine the seasonal patterns of rhizome growth and nutrient dynamics of the energy crop reed canary grass (Phalaris arundinacea L.) in ley I and II, and (2) to evaluate the roles of soil type (mineral vs. organic), fertilisation level (0, 50, and 100 kg N ha^?1s), and season/harvest time (Oct-96, May-97, and Aug-97) on the rhizome growth and nutrient dynamics by means of a factorially designed experiment. The general pattern of rhizome growth was that biomass was low in June during initiation of shoot growth, but increased steadily during the growing season, reached a peak in late autumn, and remained high until next spring. The N and P accumulation in rhizomes followed a similar pattern. During ley years I and II, reed canary grass rhizome growth was less dependent on soil type, and more dependent on fertilisation and season, with fertilisation being the most important predictor of growth. The season/harvest time, followed by soil type, was the most important factor for both concentrations and therefore total uptake of N, P, and K in rhizomes. Soil type affected N content in rhizomes significantly, and also interacted with season and enhanced the effect on N, P, and K content in rhizomes. The seasonal dynamics of the nutrient content in rhizomes indicate a remobilisation of the nutrients from rhizomes to the regrowth of shoots and roots in spring and relocation/storage from aboveground shoots to rhizomes during late summer and autumn. The results of this study suggest that delaying the harvest to later than October would result in considerably more energy and nutrient resources being translocated from aboveground shoots to rhizomes for growth in the next season.     

南川升麻的化学成分和抗菌活性研究

[目的]研究南川升麻化学成分的抗菌活性。[方法]采用回流提取法提取升麻根茎中的化合物,然后依次用石油醚、乙酸乙酯和正丁醇萃取,乙酸乙酯部位经硅粗胶拌样后进行硅胶层析,然后用氯仿-无水甲醇(10∶0→0∶10,V/V)梯度洗脱,通过薄层层析检测合并相同的部分,并取3、4和5化合物进行抑菌试验。[结果]从南川升麻的干燥根茎中分离得到6个化合物,其中3个为环菠萝蜜烷型三萜,通过光谱和质谱分析将他们的结构分别鉴定为异阿魏酸(1)、阿魏酸(2)、25-O-乙酰升麻醇(3)、兴安升麻苷C(4)、12β-羟基升麻醇(5)和β-谷甾醇(6)。[结论]首次从该植物中分离得到1～6化合物,其中3、4和5化合物都有较好的抗菌活性。     

自然保护区内毛竹竹鞭的动态生长研究

对天目山自然保护区内的毛竹竹鞭进行了为期1年的动态生长跟踪试验研究。结果表明,毛竹竹鞭的年生长量进程表现出＂慢-快-慢＂的节律,鞭梢直径的生长进程与之基本一致;7～9月为竹鞭速生期,也是其最佳生长时期。水平方向上,竹鞭的延伸方向以＂向前＂为主,极少发生转弯现象;垂直方向上,竹鞭的延伸方向以＂向下＂为主,＂平行＂生长也较多发生。毛竹属典型的浅根竹种,竹鞭分布范围为0～50 cm土层,主要分布在0～20 cm土层。     

春兰与大花蕙兰杂交后代根状茎增殖与分化条件

为了筛选适合根状茎增殖分化的条件,以春兰Cymbidium goeringii与大花蕙兰Cymbidium hybridum杂交后代的根状茎为材料进行培养,比较了不同基本培养基、植物生长调节物质和有机添加物等对根状茎增殖与分化的影响。结果表明:1/2MS(Murashige and Skoog)培养基对杂交根状茎增殖与分化效果最适宜;2,4-二氯苯氧乙酸(2,4-D)和激动素(KT)对杂交组合春兰与大花蕙兰‘梦境’‘Wanderland’的根状茎分化作用不显著,1/2MS培养基添加1.0mg·L-16-苄基腺嘌呤(6-BA)+1.0 mg·L-1萘乙酸(NAA)对春兰与大花蕙兰‘梦境’的杂交后代增殖分化效果最佳;使用有机添加物对根状茎增殖有显著影响,其中以椰汁增殖效果最好,其次为香蕉泥、土豆汁;添加100 g·L-1香蕉泥+50 mL·L-1椰汁最利于根状茎的增殖与分化。图1表4参16