DROUGHT STRESS: Soil Water Availability Alters the Inter‐ and Intra‐Cultivar Competition of Three Spring Wheat Cultivars Bred in Different Eras     

L. Song  D.‐W. Zhang  F.‐M. Li  X.‐W. Fan  Q. Ma  N. C. Turner 《Journal of Agronomy and Crop Science》2010,196(5):323-335

Competition for water generates a classic aspect of the tragedy of the commons, the ‘race for fish’, where crops must allocate more resource to acquisition of the limiting resource than is optimal for crop yield allocation. A pot experiment using a simple additive (target–neighbour) design was conducted to examine the above‐ground and below‐ground growth of three spring wheat (Triticum aestivum L.) cultivars when grown alone and in mixtures at three levels of water availability. The effects of competition and water availability were compared by observing patterns of growth, biomass allocation and below‐ground outcomes. Competitive interactions were investigated among cultivars ‘HST’, ‘GY602’ and ‘LC8275’, target plant of each cultivar grown without neighbouring plants are referred to herein as control plant and one target plant of each cultivar sown surrounded either by same or another cultivar as intra‐ or inter‐cultivar competition. Competitive ability was assessed as the response ratio (lnRR) between the target plant surrounded by six other plants and the target plant in isolation. Our results showed that the cultivar ‘HST’, released over a century ago, produced a higher biomass and grain yield than the more recently released cultivars ‘LC8275’ and ‘GY602’ when grown as isolated plants with sufficient water supply. However, competition for resources from neighbours led to target plant biomass and grain yield being significantly reduced relative to controls in all three cultivars, particularly in ‘HST’. When subjected to intra‐cultivar competition, the two recently released cultivars ‘LC8275’ and ‘GY602’ had higher grain yields and water use efficiency for grain than ‘HST’ in all three water regimes. The landrace ‘HST’ had better and significantly linear relationships between biomass and biomass allocation, root length and specific root length, whereas the recent and modern cultivars had much more water‐related species‐specific changes in root morphology and allocation patterns. These results suggest that crop traits that influence competitive ability, such as biomass allocation to roots and root plasticity in response to drought have changed in modern wheat cultivars because of breeding and selection.  相似文献   

Classification of Tomicus Species     

Li Xia  Zhang Zhen  Cao Peng  Wang Hongbin  Han Pingding 《中国林业科技(英文版)》2012,(3):45-45

Both morphological characters and a portion of of 28S rDNA sequences were used to identifying Tomicus species.The specimens were classed into groups with the following characters: 1) granules or punctures on interstria 2 on the declivity of the elytra;2) length of the elytral interstrial hairs and hairs arising from punctures;3) arrangement of pronotal punctures and hairs.These characters could be clearly examined under a binocular microscope at 30×magnification and they were applicable and valuable for the forest entomologists to identify Tomicus species.The phylogenetic tree established with difference in 28S rDNA sequence of D2 region revealed that the specimens of each group identified by morphological characters were also grouped together.The genetic distances of intra-species, inter-species and inter-genus were not overlapped. Genetic divergence of 28S rDNA was also useful for identifying Tomicus species.  相似文献   

A new and unusual species of Parachiton (Mollusca: Polyplacophora) from South Africa     

《African Zoology》2013,48(1):93-98

A new species of the genus Parachiton, P. hodgsoni n.sp., which inhabits shallow water off the South African coast, is described. The radula is unusual for the genus Parachiton. It consists of about 160 transverse rows of very small mature teeth of which the major lateral teeth have very narrow tridentate cusps. The intermediate valves are granulose with the granules arranged in widely spaced, longitudinal rows on the central area of the valves. There are 20–31 longitudinal rows on the central areas of the intermediate valves. Variability in the morphology of the tail valve is shown.  相似文献   

Phenotypes Including Immunocompetence in Scavenging Local Chicken Ecotypes in Tanzania     

Msoffe PL  Minga UM  Olsen JE  Yongolo MG  Juul-Madsen HR  Gwakisa PS  Mtambo MM 《Tropical animal health and production》2001,33(4):341-354

A study was conducted to determine the variations in physical characters and immunocompetence among scavenging local chicken ecotypes in Tanzania. Eighty-four adult scavenging local chickens from four eco-climatic regions of Tanzania were studied. Measurements of adult body weight, body length, shank length and egg weight and observations of plumage colour and pattern, earlobe colour, skin colour and the shape of the comb were conducted. The antibody response to sheep red blood cells, serum haemolytic complement and the cutaneous response to phytohaemagglutinin-P were assessed. Five ecotypes were identified and named Mbeya, Morogoro-medium, Ching'wekwe, Kuchi and Singamagazi. Singamagazi and Kuchi were significantly heavier, with longer shanks and heavier eggs than the other ecotypes. The average adult body weight for males ranged from 1621 g (Mbeya) to 2915 g (Singamagazi). Average female weights ranged from 1108 g (Morogoro-medium) to 2020 g (Singamagazi). Mean egg weights ranged from 37.65 g (Ching'wekwe) to 45.61 (Singamagazi). The Kuchi had mostly rose and walnut combs, while the other ecotypes were mostly single combed. In each ecotype there were chickens with a high or low antibody response to red blood cells, but there was a significant difference between the ecotypes.  相似文献   

Effects of Lactobacillus and Bacillus subtilis Mixed Fermentation Feed on Growth Performance,Slaughter Performance and Intestinal Morphology of Broilers     

CHEN Zhimin  ZHENG Aijuan  CHANG Wenhuan  CAI Huiyi  LIU Guohua 《中国畜牧兽医》2007,47(12):3909-3916

The purpose of this experiment was to study the usage and proportion of fermented feed in broiler feed.By adding 0,10% and 20% fermented complete formula feed to the broiler feed,and granulating normally,the influence of the usage mode of the fermented feed on the production performance,slaughter performance,intestinal tract and other related indexes of the broiler feed were studied,so as to provide reference for the application of the fermented feed in the broiler feed.180 1-day-old healthy AA male broilers were randomly divided into 3 groups with 6 replicates in each group and 10 chickens in each replicate.The three treatment groups were fed with 0,10% and 20% of the total fermented feed for 42 days.The results showed that:From the whole period (1-42 days old),the 10% fermentation feed substitution group significantly reduced the feed consumption and weight gain ratio (P<0.05),and the average daily weight gain increased (P=0.05).At 42 days old,there was no significant effect of fermented feed on slaughter performance (P>0.05).The ileal crypt depth of broilers in the 20% fermentation feed replacement group was significantly higher than that in the control group and the 10% replacement group (P<0.05).The length of duodenal villi and V/C in 20% and 10% fermentative feed substitution group was significantly higher than that in control group (P<0.05).The results showed that the replacement of 10% fermented feed in broiler feed could reduce the ratio of feed to weight gain,increase the average daily gain,and have a certain impact on intestinal development.  相似文献   

膨化与加酶玉米对断奶仔猪生长性能和肠黏膜形态的影响   总被引：1，自引：0，他引：1  

王潇  何瑞国  刘俊熙 《中国兽医学报》2006,26(1):94-97

通过2个饲养试验，研究了膨化及加酶处理玉米对断奶仔猪的生长性能和肠黏膜形态的影响。试验一分别用普通玉米、膨化玉米、普通玉米加酶及膨化玉米加酶为主要能量原料的饲料饲喂仔猪做4种处理，每个处理6个重复，定时记录体质量和耗料量．计算日增重、日采食量和料肉比。结果表明，膨化和加酶玉米均可提高日增重，降低料肉比。试验二分别用普通玉米、膨化玉米、普通玉米加酶及膨化玉米加酶为主要能量原料的饲料饲喂仔猪做4种处理，每个处理6个重复，分别在断奶后第14天和第28天各屠宰1头公猪。取十二指肠、空肠前、中、后段以及回肠做组织切片，观察其黏膜厚度、绒毛高度、隐窝深度和绒毛宽度。结果表明，断奶后14d，与普通玉米组相比，膨化玉米组和加酶玉米组都显著提高了十二指肠的绒毛高度，二者共同处理组使十二指肠的绒毛高度极显著提高；2种处理组都显著降低了空肠中段的隐窝深度；显著增加了十二指肠、空肠前段、后段和回肠的黏膜厚度。断奶后28d，2种处理组都显著增加了十二指肠的黏膜厚度。  相似文献   

Change in flower morphology of Torenia fournieri Lind. induced by forchlorfenuron application     

Takaaki Nishijima  Koji Shima 《Scientia Horticulturae》2006

We induced various flower morphologies in torenia (Torenia fournieri Lind.) by the application of forchlorfenuron (CPPU). Those morphologies were the combination of four basic morphological changes, the development of serrate petals, incised petals, a paracorolla, and an increased number of floral organs. These morphological changes occurred systematically depending on the floral stage at the time of CPPU application. Serrate petals were induced when CPPU was applied during the stages of corolla development, whereas application at younger stages induced petal incision. The serrate petal margin resulted from preferential proliferation of cells around the vascular bundles, whereas petal incision likely resulted from the lateral outgrowths of petal. A paracorolla was induced at the adaxial petal face when CPPU was applied between the sepal development stage and early corolla development. The paracorolla appears to have arisen from the lateral outgrowths of the stamen. The numbers of stamens, petals, and sepals increased when CPPU was applied at and before the differentiation of sex organs and the corolla. Enlargement of the floral meristem probably caused this increase. Application of N⁶-benzylaminopurine and zeatin did not induce these morphological changes.  相似文献   

胭脂蚧的形态特征及蜡泌物超微结构的研究     

张艳峰  谢映平  黄健 《植物检疫》2006,20(2):65-69

采用制作玻片标本和扫描电镜技术研究了胭脂蚧Dactylopius confusus（Cockerell）在不同发育阶段的显微形态特征及蜡泌物的超微形态。结果发现：1龄若虫，它的五格腺分布全身，管腺有少量分布；背刺为柱状或截锥状，呈带状分布。雌成虫，它的管腺分布整个腹面，五格腺在腹面末端成簇，在背面单个或成群分布；背刺散布全身。蜡泌物的研究发现：若虫背腹面均分泌丝状蜡，断裂后形成C型小蜡圈；背刺实为中空管，具泌蜡功能。雄茧是由蜡丝交织构成。雄蛹表面附着白色蜡粉。而雌成虫蜡被是由粗蜡管及其周围的细长蜡丝组成。  相似文献   

微生物发酵豆粕对断奶仔猪生长、血清指标及肠道形态的影响   总被引：23，自引：0，他引：23  

冯杰  刘欣  卢亚萍  刘媛媛 《动物营养学报》2007,19(1):40-43

本文旨在研究微生物发酵豆粕对仔猪生长及血清指标的影响,并且根据肠道组织形态学的微观变化,评价了不同处理的豆粕对早期断奶仔猪肠道形态的影响.选用60头35日龄断奶体重为(8.62±0.21)kg的同窝杜×长×大仔猪,分为试验组和对照组,每组3个重复,每个重复10头,分别饲喂以普通豆粕为对照组,微生物发酵豆粕为试验组的日粮.试验结果表明:饲喂微生物发酵豆粕使仔猪料重比降低8.39%(P＜0.05),腹泻指数降低39.96%(P＜0.01),血清尿素氮含量降低39.47%(P＜0.01),血清IgG含量降低6.35%(P＜0.05).豆粕经微生物发酵后减轻饲粮中大豆蛋白对肠道的过敏损伤,使肠道维持良好的结构形态,从而促进营养物质的消化吸收.  相似文献   

秆野螟属(Ostrinia)系统进化与分类研究进展   总被引：5，自引：0，他引：5       下载免费PDF全文

杨瑞生  ;王振营;何康来 《植物保护》2007,33(2):20-26

秆野螟属(Ostrinia)昆虫全球分布20种,寄主广泛,在农业生产中具有重要的经济意义。由于该属地理分布广泛,形态特征复杂,寄主和生态区重叠严重,秆野螟属系统发育研究还存在很多问题尚未解决。本文综合中国秆野螟属分类概况,对目前应用于秆野螟属系统发育研究的各种性状,包括形态特征、性信息素(生殖隔离)以及分子水平的研究进展作了阐述,并针对秆野螟属研究内容的复杂性及其研究现状,提出了相关对策。  相似文献