Yield and morphological responses of a forage sorghum to mefluidide     

D I Bransby  A G Matches  C R Richardson 《African Journal of Range and Forage Science》2013,30(2):47-51

Abstract

Due to rapid growth, stem build‐up in forage sorghum crops often leads to considerable wastage by animals and consequent loss of production. In this study the potential of the chemical plant growth regulator, mefluidide, for modifying the morphology of forage sorghum was examined. Mefluidide was applied to two consecutive plantings of forage sorghum at 0; 0,14 and 0,28 kg/ha. Treatment with mefluidide suppressed stem elongation of sorghum plants and stimulated tillering 4–6 weeks after application. After 6 weeks the stem:leaf ratio of treated plants was significantly lower (P ≤0,05) than that of control plants. On average, total dry matter (DM) yield was marginally higher for the control, but DM yield of leaf material was significantly higher. (P ≤0,05) for treated plots from 6 weeks after mefluidide application. No significant differences were observed between levels of mefluidide but responses of different variables over time differed between plantings. This was associated with different stages of plant growth when mefluidide was applied and different environmental conditions for two plantings.  相似文献   

铁皮石斛茎段丛生芽的增殖培养研究     

姜殿强  潘梅  黄赛  云勇 《安徽农业科学》2013,41(5):1905-1906,1940

[目的]研究铁皮石斛茎段丛生芽的最适增殖培养方式。[方法]以铁皮石斛茎段为外植体,研究不同基本培养基、植物生长调节剂种类和浓度、有机添加物及培养时间对铁皮石斛丛生芽增殖的影响。[结果]MS培养基优于1/2MS、B5和N6;香蕉对丛生芽的分化有明显的促进作用;培养60 d时丛生芽的增殖倍数最高,生长势好。[结论]丛生芽的最佳增殖培养基为MS+6-BA 2.0 mg/L+NAA 0.5mg/L+香蕉100 g/L+活性炭0.5 g/L,培养时间以60 d为宜。  相似文献   

两系杂交中籼皖稻153抗倒特性分析     

彭苗苗  杨亚春  李莉  倪大虎  杨剑波 《安徽农业科学》2013,(29):11620-11621,11635

[目的]揭示皖稻153抗倒特性强的成因。[方法]对两系杂交中籼皖稻153和其双亲及部分同型主栽组合等茎秆和根系性状进行测量和分析。[结果]皖稻153较之其他参试品种,在茎秆性状上具有适中的株高和较强的抗折力;在根系性状上具有丰富的根系数量和明显的根长优势。[结论]皖稻153表现出较小的倒伏指数和较强的抗倒能力。  相似文献   

Snow damages on trees of an uneven age in mixed broadleaf forests:effects of topographical conditions and tree characteristics     

Farzam Tavankar  Angela Lo Monaco  Mehrdad Nikooy  Rachele Venanzi  Amireslam Bonyad  Rodolfo Picchio 《林业研究》2019,(4):1383-1394

Snow damage on natural stands is an important problem concerning mountainous forest management.In the present research,the frequency and intensity of heavy snow damage on natural stands and the relationship of damages with characteristics of trees,stand and topography were studied in mountainous forests of northern Iran.A systematic sampling design was applied to the study area(140 ha),with 122 circular plots.The grid dimension was100 m and each plot area was 1000 m^2.The four types of snow damage to trees include:crown damage(8.6%),stem breakage(5.4%),uprooting(3.2%),and bending(1.4%).The frequency of crown damage grew with an increase inthe diameter at breast height(DBH),while the frequency of stem breakage,uprooting and bending decreased with an increase the DBH.The frequency of crown damage,stem breakage,and total damages was related to tree species(p<0.01).Not all tree species were equally susceptible to snow damage.The amount of damage grew with increasing elevation and slope angle and decreased with increasing soil depth.Young trees(DBH<25 cm)were more susceptible to snow damage than other trees.Snow damage decreased by as the trees in the stand became more mixed in age.The susceptibility of trees to snow damage increased by height and slenderness coefficient.With adequate silvicultural operation,snow damage can be reduced to a minimum level in these natural forests.  相似文献   

Distribution of stem decay in the beech trees of the Azerbaijan and its impact on the output of commercial wood     

A.B.Yakhyaev  V.S.Farzaliyev  E.P.Safarova 《林业研究》2019,(3):1023-1028

To determine the distribution of stem decay in the beech stands of Azerbaijan, we sought to identify the species, number, and height of attachment of fruiting bodies;the extent of decay in tree trunks growing under different conditions;and its influence on the trees’ commercial wood. The research was conducted on three farms representing the most common forest types of the Greater Caucasus within Azerbaijan. Examination of the presence of fruiting bodies in the tree trunk revealed that stem decay is the most common infection in beech (Fagus orientalis) stands, especially in fresh, moist areas, with less infection under dry growing conditions. In this work, the length, diameter, and volume of decay were studied by infecting the trunks of 93 model trees affected with mushrooms in 1–4 m cuttings. Our results showed that as the age of the stand increased, extent, diameter, and volume of decay increased significantly: the extent of decay from 1.47 to 6.43 m;the diameter of the decay from 8.15 to 32.7 cm;and the volume of decay from 2.5 to 13.2%. The relationship between age and the specified indicators is presented graphically. Using data obtained from the same sample of trees, we determined the expected and actual yield of commercial wood by age class. We determined that stem decay in beech stands leads to a decrease in the yield of commercial wood on average from 25.1% in the middle-aged to 14.8% in overmature plantations, respectively, with an estimated yield of 40.8–62.7%. Here we present mathematical models of the output of commercial wood from the infected part of the stands by age classes with the use of average data on the extent of decay in model trees.  相似文献   

不同叶面肥对紫花苜蓿生长、产草量和品质的影响及效益比较     

李丹丹  巩皓  刘国富  闫得朋  袁玉莹  肖知新  白珍建  崔国文 《草地学报》2019,27(6):1718-1724

喷施叶面肥是提高苜蓿产草量和品质的有效措施之一。为探明不同叶面肥成分对紫花苜蓿（Medicago sativa L.）生长、产草量和品质的影响,并筛选紫花苜蓿优质高产的叶面施肥方案,本试验以生长第2年的‘东农1号’紫花苜蓿（Medicago sativa L.‘Dongnong No.1’）为材料,在春季返青期一次性土壤施肥基础上,于刈割前20天分别喷施苜蓿专用叶面肥（自主研制,专利申请号：201810124670.2）、0.3%尿素、0.5%磷酸二氢钾、0.3%尿素+0.5%磷酸二氢钾、0.3%尿素+0.1%硫酸亚铁+0.05%钼酸铵、0.5%磷酸二氢钾+0.1%硫酸亚铁+0.05%钼酸铵,0.3%尿素+0.5%磷酸二氢钾+0.1%硫酸亚铁+0.05%钼酸铵这7种叶面肥（分别简称叶面肥A,B,C,D,E,F,G）,以喷施清水为对照,每年刈割3茬,观测不同叶面肥对‘东农1号’紫花苜蓿高度、茎叶比、产草量和营养品质的影响,并进行经济效益比较分析。结果表明：喷施叶面肥均可显著提高紫花苜蓿垂直高度、产草量和粗蛋白含量;其中叶面肥G处理下,全年总干草产量达14 595.81 kg·hm^-2,比对照提高17.70%;平均粗蛋白含量为25.43%,比对照提高3.12%。叶面肥A处理纯增经济效益和产投比分别达2 414.57元·hm^-2和2.63,是叶面肥G处理的2.65倍和8.77倍。经过综合比较分析,在寒地黑土农区喷施紫花苜蓿专用叶面肥（A处理）相对投入较少,产出较多,综合效益最高。  相似文献   

用于连接离合器毂与带轴齿轮的组件及方法研究     

张克青  段华荣  王林军  王治军  葛便京 《拖拉机》2014,(6):54-59

提供了一种用于连接＂离合器毂与带轴齿轮＂的压配焊合组件及使用方法,即通过对其组件及使用方法的研究,不仅可以有效地解决离合器毂与带轴齿轮在压配连接后易出现的变形问题,而且还可以有效地控制其焊合连接后的变形情况,从而达到提高压配焊合质量的目的。该压配焊合组件,结构新颖简单,使用方法独特易行,已推广应用,并收到良好的效果,且已申报了国家发明专利。  相似文献   

Review on the Influence of Bushwood Stem Flow and Root-induced Preferential Flow on the "Soil Fertile Island effect" of Nebkha北大核心CSCD     

Yu H.-L.  Fan J.  Niu Y.-B.  Zhu W.-W.  Huang J.-Y. 《草地学报》2019,(1):1-7

The enrichment functions of stem flow and root-induced preferential flow of bushwood are of great importance in the formation and growth and evolution of the fertile island of nebkha. It enhances the vegetation adaption to dry and infertile environment and the stability of ecosystem, thereby plays important eco-hydrological roles in plant reconstruction in desert regions. Making clear the temporal and spatial responses of shrubs to the changes of soil water content during the process of the nebkhas evolution, the maintaining mechanism of biodiversity, and the ecological adaption countermeasure of vegetation to soil water is the keys to further study the formation and evolution of nebkha. In this paper, the formation mechanism of nebkha was reviewed,soil hydrologic process and vegetation response during the nebkha evolution process and the influences of stem flow and root-induced preferential flow of shrubs on the soil fertile island were demonstrated, and the study methods of stem flow and root-induced preferential flow of shrubs were summarized as well. For better evaluating the function of stem flow to the stability of shrub communities and the development of ecosystems in desert regions, more attentions should be paid on the root distribution of shrubs and the movement and redistribution of water and nutrition along with preferential flow path caused by shrub roots in the future research. © 2019 China Agricultural University. All rights reserved.  相似文献   

From viruses to cancer stem cells: dissecting the pathways to malignancy     

Argyle DJ  Blacking T 《Veterinary journal (London, England : 1997)》2008,177(3):311-323

Cancer is a disease of all vertebrate species and has been well documented throughout history with fossil records indicating that dinosaurs of the Jurassic period suffered from the disease. The Greek physician, Galen is accredited with describing human tumours as having the shape of a crab, with leg like tendrils invading deep into surrounding tissues--hence the term cancer. Today cancer can be defined as any malignant growth or tumour caused by abnormal and uncontrolled cell division that is able to invade tissues locally and spread to other parts of the body through the lymphatic system or the blood stream. This is obviously a simplistic attempt at describing a complex disease that can utilize a myriad of biological pathways to sustain growth and proliferation. Dissecting these pathways has been the challenge of cancer researchers for decades in the search for new treatment strategies. This review attempts to condense our understanding of cancer and to offer insights into an alternative theory regarding the existence of true cancer stem cells and how this will inform the development of new therapeutics.  相似文献   

化学预处理对稻草硅化程度的影响及其对瘤胃降解率的改善效果     

王佳垄  叶丹妮  李文婷  刘建新 《动物营养学报》2008,20(2):170-175

本试验结合化学分析与电镜技术,探讨了氨化与碱化处理对稻草硅化程度的影响,分析了稻草硅化程度与降解率的相关性。化学分析显示,碱化或氨化处理稻草的总硅含量随氢氧化钠或碳酸氢铵处理剂量的增加而线性下降(P<0.01);可溶性硅含量随碳酸氢铵处理剂量的增加变化不显著(P>0.05),但随氢氧化钠处理剂量增加线性下降(P<0.01);总硅与稻草干物质降解率间存在极显著负相关(r=-0.560,P<0.01)。电镜观察发现,氢氧化钠处理的稻草茎表皮根毛皱缩、乳突和瘤状结构部分溶解,碳酸氢铵处理的稻草茎外表皮层部分脱落;氢氧化钠处理的稻草茎表皮有明显的降解优势,碳酸氢铵处理的稻草茎表皮瘤胃降解72h后仍保持完整的乳突和瘤状结构。上述结果表明,氨化和碱化处理可以在一定程度上降低稻草的硅化程度,借此提高稻草的降解率,但两者降低稻草硅化的程度与方式不同。氨化处理通过使稻草表皮层部分脱落,降低稻草总硅含量,但借此提高稻草降解率的作用较弱;碱化处理可使稻草表皮硅酸盐部分溶解,从而使稻草总硅含量、可溶性硅含量下降,加速稻草降解。  相似文献