Assessment of allelopathic potential of barnyard grass (Echinochloa crus-galli) on rice (Oryza sativa L.) cultivars

Laboratory, greenhouse and field studies were conducted to assess the allelopathic potential of 44 rice cultivars (Oryza sativa L.) on barnyard grass (Echinochloa crus-galli P. Beauv. var. oryzicola Ohwi). Rice cultivars exhibited marked differences in the inhibition of barnyard grass growth and development. In the laboratory, Gin shun rice cultivar extracts exhibited the greatest activity on the weed seedling growth, reducing dry weight by 61%, while Kasarwala mundara cultivar extracts exhibited the greatest activity on seed germination, reducing germination by 23% and germination speed by 46%. In a greenhouse study of a residue mixture, the Philippine 2 cultivar showed the greatest inhibition percentage on seedling emergence (57%), total seedling length (74%) and dry weight (73%). In the field study, the Juma 10 cultivar demonstrated the most inhibitory effect by reducing barnyard grass tiller number (80%), leaf area (49%) and leaf (61%) and stem (74%) dry weight (68%). These results suggest that there are differences among the varieties for allelopathic inhibition of barnyard grass, and that the development of barnyard grass suppressive rice cultivars that have greater allelopathic potential may be possible.     

耐黄腐酸水稻品种筛选及其生理响应

前期研究发现,在淹水条件下黄腐酸能显著抑制稗草生长,具有防控水田稗草的潜力,而评估黄腐酸对水稻的安全性是利用其进行稻田稗草防治的重要前提,因此,对水稻安全性进行系统测评具有重要意义.本研究在模拟田间淹水条件下加入0.8 g/L黄腐酸溶液处理24个水稻品种幼苗,测定其株高、根长和株鲜重的抑制率,筛选出耐黄腐酸水稻品种并对...     

嘧草醚不同剂型对水稻移栽田稗草的防效及安全性试验

嘧草醚是防除水稻移栽田稗草的除草剂,为了验证不同剂型对其防效及安全性的影响,特进行田间药效试验。结果表明,嘧草醚不同剂型对水稻均安全,且对稗草的防效没有明显差异。     

寒地水稻移栽田防治稗草分期施药技术研究

针对常规寒地水稻移栽田前期除稗剂多采用一次性施药,药效和安全性差的问题,通过对寒地水稻移栽田稗草的防治采取插前5～7 d、插后15～20 d分期施药试验研究,结果表明:分期施药对稗草防治效果好,提高了对水稻的安全性。     

Effects of alfalfa leaf extracts and phenolic allelochemicals on early seedling growth and root morphology of alfalfa and barnyard grass

Alfalfa (Medicago sativa L.) plants contain water-soluble substances that are autotoxic as well as allelopathic to other plants. Laboratory experimentation through a petri dish assay with imbibed seeds was conducted to evaluate the phytotoxic effects of alfalfa cv. “Vernal” leaf extracts, coumarin, trans-cinnamic acid, o-coumaric acid, and hydro-cinnamic acid on the seedling growth and anatomical responses of 6 day-old alfalfa and barnyard grass. With increasing concentration, the alfalfa leaf extracts significantly reduced root lengths of alfalfa and barnyard grass (Echinochloa crus-galli, Beauv. var. oryzicola Ohwi). Coumarin, trans-cinnamic acid, o-coumaric acid, and hydro-cinnamic acid at 10⁻⁴ M significantly reduced root lengths of alfalfa and barnyard grass. The root systems, especially root tips of alfalfa, were stunted and swollen by the aqueous alfalfa leaf extracts at 30 g l⁻¹ and coumarin at 10⁻³ M. This research suggests that alfalfa plant extracts significantly affected root growth and morphological differentiation of susceptible plants, resulting in reduction of their biomass in the presence of either autotoxic or allelopathic compounds. The results may have value in enabling weed control based on natural plant extracts.     

寒地水稻移栽田防治稗草分期施药技术研究

针对常规寒地水稻移栽田前期除稗剂多采用一次性施药,药效和安全性差的问题,通过对寒地水稻移栽田稗草的防治采取插前5～7 d、插后15～20 d分期施药试验研究,结果表明：分期施药对稗草防治效果好,提高了对水稻的安全性。     

Induced Effects of Exogenous Phenolic Acids on Allelopathy of a Wild Rice Accession （Oryza Iongistaminata, S37）

Four exogenous phenolic acids, including salicylic acid, fumalic acid, p-coumaric acid and p-hydroxybenzonic acid, were used to investigate the regulatory effects on allelopathy of a wild rice accession of S37 (Oryza longistaminata), which is a known allelopathic rice. The four exogenous phenolic acids induced the enhancement of the allelopathic potential of wild rice S37 in target weeds though the weed-suppressive activities were low, and the inducible effects were dependent on the specific phenolic acid, concentration and treatment time. After foliar application of exogenous phenolic acids, the inhibition rates for plant height, root length and fresh weight of barnyard grass (Echinochloa crus-galli) were significantly higher than those of the control. Especially at the concentration of 100 mg/L, the inhibition rates for plant height and fresh weight of barnyard grass by fumalic acid were 38.12% and 26.31% higher than those of the control, showing that fumalic acid was more effective compared with other phenolic acids in inhibiting monocotyledon weed growth. Furthermore, the weed-suppressive activity of aqueous extract from the leaves of wild rice S37 treated with exogenous phenolic acids was increased, and it peaked at 48 h after the treatment with the aqueous extract, and then gradually declined.     

不同肥力和密度下玉米田杂草群落的研究

应用群落生态学方法,对玉米田杂草群落进行调查研究,探讨不同肥力和密度下玉米田杂草的群落组成、多样性和稳定性。结果表明,玉米田优势种杂草为稗草、红蓼、反枝苋、圆叶藜,其中稗草综合优势度最高。施肥可增加杂草数量和生物量,肥力和密度分别对群落中不同物种的综合优势度产生不同影响,并对玉米田杂草群落的组成、多样性和稳定性产生影响。     

电子记录稻飞虱取食和产卵行为及其在植物抗虫性研究中的应用

采用AC型电子记录系统(EMS)对褐飞虱在非寄主植物稗草和具有抗性基因bph4的水稻品种Babawee上的取食行为进行了比较研究.结果表明,褐飞虱口针到达稗草韧皮部以前停止取食,这揭示了在稗草非韧皮部组织中存在拒食剂.而在抗虫品种上,口针到达韧皮部以后取食行为终止.因此,可以清楚地识别两类具有不同抑制取食抗性因子的抗性植物.分析白背飞虱产卵行为的电子记录表明,在大多数情况下,就旺盛生长的水稻植株的下半部分而言,白背飞虱产卵器插入植物组织中但不产卵.这表明旺盛生长的植株能诱导白背飞虱的产卵行为,但由于某些拒避性因素使整个产卵过程不能完成.因此,这一系统可以有效地识别具有产卵抗性的植物上行为序列中受到破坏的步骤.     

吉林省中部地区玉米田杂草种类及其优势种群调查报告

掌握不同生态条件下的玉米田杂草发生种类及优势种群情况,对于制定杂草综合治理方案,科学选用化学除草剂及其配套技术具有十分重要的指导意义.本文选用倒"W"型9点取样法,对吉林省主要玉米产区的玉米田杂草发生情况进行了普查.结果表明,我省中部地区玉米田杂草种类有16个科,35种.相对多度较大的有稗草、苣荬菜等十余种。     

耒阳烟区烟草有害生物调查研究

2012年11月至2013年7月,对耒阳市烟区开展了烟田病虫草害普查。结果表明,危害耒阳市烤烟的主要病害有12种,其中病毒性病害3种：烟草普通花叶病、烟草黄瓜花叶病毒病、马铃薯Y病毒病;烟草真菌性病害5种：黑胫病、炭疽病、蛙眼病、赤星病、根腐病;烟草细菌性病害3种：青枯病、野火病、空茎病;气候型斑点病。耒阳烟田害虫有6种：烟蚜、烟青虫、斜纹夜蛾、小地老虎、野蛞蝓、蜗牛。烟田杂草主要有稗草、看麦娘、蓼草、革命草、马鞭草等。     

8种稗草(Echinochloa）对扫茀特耐药性的比较

2001年10月采集南京地区8种稗草（Echinochloa）种子,分别用0、0.01、0.10、1.00、10.00 mg/L扫茀特浸稗草种子,萌发后测定其形态、结构及α 淀粉酶活性。结果表明,无芒稗的株高、叶片及叶鞘细胞的长度、α 淀粉酶活性受扫茀特抑制的程度最低,旱稗、稗、西来稗次之,光头稗最高。说明不同稗草的种及变种间存在耐药性的差异,其中无芒稗的耐药性最强,光头稗最弱。关键词:     

不同药剂防治水稻插秧田杂草试验总结

通过对施用不同药剂配方防治水稻插秧田杂草的对比试验研究,结果表明:3个处理药剂和对照药剂对水稻生产安全、无药害表现,对稗草、泽泻、狼巴草、慈菇防效在91.1%～100%,增产12.07%～15.17%,可在生产中推广应用。     

稻鸭共栖试验研究

通过稻鸭共栖种养结合模式和常规种稻对比试验研究,结果表明:稻鸭共栖中鸭子除了对矮慈姑和稻稗的防效很差外,对其他几种杂草的防效均和化学防治区相近;鸭子在田间活动能显著降低害虫基数并减轻危害程度;稻鸭共栖处理的水稻稻米品质好而且稻田鸭瘦肉率高,价格偏高。稻鸭共作可获得净利1 106元/667 m2,比常规稻作550元/667 m2高556元/667 m2。     

Deep Root Water Uptake Ability and Water Use Efficiency of Pearl Millet in Comparison to Other Millet Species

Abstract

Pearl millet is better adapted to hot and semi-arid conditions than most other major cereals. The objective of this study was to compare the deep water uptake ability and water use efficiency (WUE) of pearl millet among millet species. First, the WUE of six millet species was evaluated in pots under waterlogging, well-watered (control), and drought conditions. Secondly, the water uptake from deep soil layers by pearl millet and barnyard millet, which showed the highest drought and waterlogging tolerance, respectively, was compared in long tubes which consisted of three parts (two loose soil layers separated by a hardpan and a Vaseline layer). Soil moisture was adjusted to well-watered and drought conditions in the upper (topsoil) layer, while the lower (deep) layer was always kept wet. WUE was significantly reduced in all millet species by waterlogging but not by drought. The ratio of WUE to the control condition indicated that pearl millet had the highest and lowest resistances to drought and waterlogging conditions, respectively, while barnyard millet was the most stable under both conditions. The deuterium concentration in xylem sap water, relative water uptake from deep soil layers, and water uptake efficiency of deep roots were significantly increased in barnyard millet but not in pearl millet by drought in topsoil layers. In conclusion, the drought resistance of pearl millet is explained by higher WUE but not by increased water uptake efficiency in deep soil layers as compared to barnyard millet, another drought-resistant millet species.     

Characterization of starches of proso,foxtail, barnyard,kodo, and little millets

Scanning electron microscope (SEM) pictures of small millet starch granules showed more large polygonal and few small spherical or polygonal granules. The granules of small millets resembled those of rice starch granules. The size of the starch granules ranged from 0.8–10 m. The size of the granules was larger in barnyard millet and smaller in proso millet. Several granules showed deep indentation caused by protein bodies. SEM of starch isolated from 24 hour-germinated kodo millet showed pitting or pinholes at some points due to the attack of amylases (preferentially on bigger granules). Brabender viscoamylograph studies on small millet starches revealed that the gelatinization temperatures ranged from 75.8 to 84.9 ^° C. Barnyard millet possessed lower amylograph viscosity, minimum breakdown, and relative breakdown values when compared to the other small millets.     

Growth of Roots Emerged from Excised Phytomers of Three Gramineous Species under a Low Osmotic Potential

Abstract

The growth of crown and lateral roots emerged from the excised phytomers of pearl millet (Pennisetum typhoideum Rich.), barnyard millet (Echinochloa frumentacea Link.) and maize (Zea mays L.) was studied under normal and low osmotic potential conditions. The plants were grown in two solutions with osmotic potentials of –0.02 and –0.54 MPa for 6 days. The relative growth rate of the roots in total length (RGR_L) , was not affected by osmotic stress in pearl and barnyard millets, but that in stressed maize was reduced to 64% of the control. Similarly, the relative growth rate of the roots in dry weight (RGR_W), was not affected by osmotic stress in pearl and barnyard millets, but significantly reduced in maize. Osmotic stress increased the specific root length of the lateral roots in pearl and barnyard millets, but did not affect that of maize. The photosynthetic rate (Pr) in the two millets was decreased to ca. 60% of the control by the stress, and that in maize was reduced to 21%. Under the stress, Pr in the three species was limited mainly by low stomatal conductance, but no clear relationship was found between Pr and osmotic adjustment of the leaf. The relative water content of the leaf was lower in maize than in the two millets. The resistance to water flow through the phytomer (R) was significantly increased by osmotic stress in maize, but not significantly in the two millets. The mean root length (RL) was decreased by the stress in maize, but not in the two millets. The maintenance of RGR_L in the two millets was associated with sustained R, RL and also with the maintenance of Pr and allocation of assimilates to roots.     

化感水稻内生真菌的分离鉴定及其发酵产物的生物学效应研究

以化感水稻品种‘PI312777’‘6173’和‘6180’为研究对象,从水稻根、茎和叶中分离获得70株内生真菌,采用形态学观察和rDNA-ITS区序列分析,对内生真菌进行分类鉴定。进一步以化感水稻‘PI312777’分离得到的粘红酵母和塔宾曲霉为试验菌株,通过不同稀释倍数的真菌发酵液对非化感水稻进行MS半固体培养基育苗试验,研究化感水稻内生真菌发酵产物对非化感水稻萌发率、株高等形态指标及苯丙氨酸解氨酶（PAL）、过氧化氢酶（CAT）和过氧化物酶（POD）活性的影响。结果表明,从供试化感水稻品种中共分离得到17种内生真菌,经rDNA-ITS系统发育树分析鉴定为10个属,这些内生真菌主要分布在曲霉属（Aspergillus）（29.63%）、青霉属（Penicillium）（16.67%）和镰刀菌属（Fusarium）（12.96%）。不同稀释浓度塔宾曲霉发酵液对水稻幼苗生长均有促生作用,其中50倍稀释浓度处理可显著提高水稻幼苗的株高、根长及POD酶活性。粘红酵母菌发酵液5倍稀释浓度可显著提高水稻幼苗的PAL酶活性并对水稻幼苗有促生作用。稗稻共生条件下,塔宾曲霉和粘红酵母发酵稀释液对水稻均有促生效应。本研究可为化感水稻内生真菌进一步应用于水稻生产实践提供有益指导。     

施N量对燕麦"保罗"鲜草产量和品质的影响

田间试验表明,燕麦新品种“保罗”在施氮量为90～135kg／hm^2的情况下,其植株鲜草和干草产量随着施氮量的增加而增加;干草中粗蛋白质、全磷、全钙、粗灰分含量随着施氮量的增加而提高,粗纤维含量则随着施氮量的增加而降低。施用氮肥不仅能增加燕麦植株营养体的产量,而且能改善干草的品质。在种植燕麦作为草食牲畜饲料时,为提高植株营养体产量和营养成分,应适当增施氮肥。     

A COMPARISON OF SPRING- AND AUTUMN-PRODUCED DRIED GRASS FOR MILK PRODUCTION

An experiment designed to compare the nutritive values for milk production of dried grasses harvested in spring and autumn is described. The DM digestibility of the spring- and autumn-dried grass was 67±7 and 66±0%, respectively. Both dried grasses were fed at two levels, 0±4 and 0±5 kg/ kg milk (4 and 5 Ib/10 Ib milk), to lactating cows in a randomized-block design experiment using 24 animals. Each animal was also given 2±5 kg hay/day (5±5 Ib) and in addition sufficient of the dried grass under investigation to meet maintenance requirements. Milk yield, milk energy output, live-weight gain and the solids not fat (SNF) and protein contents of the milk increased with feeding level. Season of dried grass harvesting had no effect on milk yield, milk energy output or live-weight change. The spring-harvested dried grass resulted in a significantly higher milk SNF content than the autumn-dried grass and also tended to reduce milk butterfat level.