Effect of Defoliation on Growth and Physiological Developments in Tubers of Purple Nutsedge (Cyperus rotundus L.)

The starch metabolism and hydrolytic enzyme activities in growing tubers of purple nutsedge (Cyperus rotundus L.) in response to defoliation were examined to elucidate the regrowth physiology of the plant. Effects of complete or partial defoliation imposed at 2 or 4 weeks (single defoliation), or 2 and 4 weeks (repeated defoliation) after emergence (WAE) on plant growth were studied.
Leaf area and leaf dry weight per plant in the control plots increased with time. In the mother tuber, dry weight and starch content were reduced by 16 % and 18 %, respectively, during the first 2 WAE, and then increased with time. Endoamylase (EC 3.2.1.1) activity of tubers (3.8 units g⁻¹ dry tuber) increased by 42 % during the first 4 WAE, but decreased rapidly up to 8 WAE.
Repeated defoliation significantly reduced the regrowth ability of nutsedge tubers when compared to single defoliation and the control. Repeated complete defoliation reduced the leaf area and leaf dry weight by 56 % and 69 %, respectively. The dry weights of mother tuber and total tubers 100 cm ⁻² were reduced by 41 % and 63 %, respectively, when compared to the control at 8 WAE. Endoamylase activity and starch content in the mother tuber in this treatment were reduced by 72 % and 56 %, respectively. Defoliation did not have any significant effect on the exoamylase activity.
Endoamylase is the major starch hydrolysing enzyme in tubers and the activity of this enzyme could be a limiting factor in regrowth of nutsedge tubers. Repeated complete defoliation effectively suppressed the regrowth of purple nutsedge.     

除草剂混用苗期茎叶喷雾防除胡麻田杂草与大面积应用示范

为达到一次使用除草剂兼防胡麻田阔叶杂草与禾本科杂草,笔者开展了2甲·辛酰溴等3种新型阔叶杂草除草剂与高效氟吡甲禾灵等7种禾本科杂草除草剂混用苗期茎叶喷雾防除胡麻田杂草试验。结果表明:40%2甲·辛酰溴EC 1500 mL/hm2或30%辛酰溴苯腈EC 1500 mL/hm2与108 g/L高效氟吡甲禾灵EC 1500 mL/hm2等7种禾本科杂草除草剂混用对胡麻田阔叶杂草均具优良防效,株防效和鲜重防效在94.17%~98.71%之间。40%2甲·辛酰溴EC 1500 mL/hm2或30%辛酰溴苯腈EC 1500 mL/hm2、80%溴苯腈SP 600 g/hm2与108g/L高效氟吡甲禾灵EC 1500 mL/hm2或10%精喹禾灵EC 900 mL/hm2、50 g/L唑啉草酯EC 1350 mL/hm2、15%炔草酯WP 750 g/hm2混用对胡麻田禾本科杂草均具优良防效,株防效和鲜重防效在97.22%~100%之间。从安全性、兼防效果、用药成本和增产效果综合评价,40%2甲·辛酰溴EC 1500 mL/hm2或30%辛酰溴苯腈EC 1500 mL/hm2+108 g/L高效氟吡甲禾灵EC 1500 mL/hm2或10%精喹禾灵EC 900 mL/hm2是苗期茎叶喷雾一次用药兼防胡麻田阔叶杂草与禾本科杂草的最佳组合,宜在胡麻生产中大面积推广应用。     

Impact of Different Weed Types on Growth and Yield of Mungbean (Vigna radiata L. Wilczek)

The influence of different weed types (grass, broadleaved and sedge species) on growth and yield parameters of mungbean ( Vigna radiata L. Wilczek) was evaluated under field conditions. The presence of all types of weeks had the most significant effect on growth and yields of mungbean. Broadleaved species alone had a greater adverse effect than grasses, and the influence of sedges was the lowest. The adverse effect of weeds was most prominent on vegetative growth. The influence on yield components reduced with time. However, the adverse impact of weeds on yields was similar to that on vegetative growth. A significant correlation between weed biomass and yield loss was observed. The study indicated the critical competitive period to be in the vegetative phase. Some possible implications for selective weeding are presented.     

膜间喷施芽前除草剂对谷子安全性及对杂草防效的影响

筛选对谷子安全且杀草效果较好的谷田芽前除草剂品种及施用剂量。以张杂谷10号为材料,针对覆膜穴播谷子膜间杂草危害问题,在前期试验的基础上选择乙草胺和异丙甲草胺两种芽前除草剂,设置不同剂量（乙草胺：2.25、4.50、6.75、9.00L/hm ²;异丙甲草胺：3.00、6.00、9.00、12.00L/hm ²）,于谷子播后苗前进行土壤处理,从出苗率、形态指标、产量考察除草剂对谷子的安全性,从杂草株数、鲜重考察除草剂的防效。结果表明：2.25L/hm ²剂量的乙草胺和3.00、6.00L/hm ²剂量的异丙甲草胺处理对谷子较安全,出苗率、株高、叶面积等形态指标与对照均无显著差异,可使谷子不同程度地增产;4.50~9.00L/hm ²剂量的乙草胺和9.00~12.00L/hm ²剂量的异丙甲草胺对禾本科杂草防效较好,最高可达99%以上,对阔叶杂草防效最高可达90%以上,但显著抑制谷子出苗、株高和叶面积,对产量也有一定影响。因此,覆膜穴播谷田应用乙草胺推荐2.25L/hm ²,异丙甲草胺推荐6.00L/hm ²,对谷子安全且能有效控制谷田杂草。     

90%盖萨林防除春玉米田杂草效果评价

1999~2000年进行了90%盖萨林水分散颗粒剂（WG）防除春玉米田杂草的效果及对春玉米的安全性田间小区试验。结果表明,90%盖萨林WG对春玉米田的藜、本氏蓼、反枝苋、龙葵等阔叶杂草有良好的防除效果,而对苍耳、苘麻及禾本科杂草防效较差。春玉米播后苗前土壤处理,适宜的用药量为90%盖萨林1620~1890(g·ai)/hm2(有效成份用量),对阔叶杂草总的株数和鲜重防效均在90%以上,在上述推荐剂量范围内对春玉米安全。     

贵州紫苏资源收集以及叶色多样性分析

为了调查贵州地区紫苏资源的多样性,研究紫苏叶色性状的差异及成因,收集并种植贵州地方栽培及野生紫苏资源53份,调查苗期叶片颜色性状,并测定其花青素及叶绿素含量。结果表明,贵州地方紫苏资源叶色有面绿背紫、全绿、全红（紫）等多种性状。全红（紫）紫苏花青素含量较高,叶绿素含量较低;绿色紫苏则相反。不同紫苏材料间,花青素含量差异最高可达到60倍,叶绿素含量差异最高在3倍左右。但是,其中有2个材料同时具有较高的叶绿素及花青素含量。叶片中花青素与叶绿素含量差异,导致贵州地方紫苏资源叶色存在着较大的多样性,该工作为紫苏资源研究打下基础。     

The Effect of Air Temperature on Growth and Alkaloidal Yield of Hyoscyamus muticus L.

The effect of natural air temperature on the vegetative growth and alkaloidal yield of H. muticus L. was studied. The highest number of branches, diameter, fresh and dry weights of stem and roots occurred in September sowing at full-flowering and fruiting stages. Relatively higher temperature in Sept. sowing favoured leaf growth (number, area and dry weight). Hyoscyamine yield in different organs of the plants sown in Sept., excessively exceeded all other sowings during flower budding and full-flowering stages. Hyoscine yield was quantitatively very small as compared with that of hyoscyamine and even could not be detected in the leaves of winter sowings during full-flowering stage.     

Allelopathic Effects in the Maize-Quelites-Agroecosystem of the Tarahumara Indians

The Tarahumara Indians of the north-west Mexican Highland practice a method of using several weeds for food which are called "quelites". These weeds play an important role in the Tarahumara diet and seem to be connected with maize-cultivation in a special way.
In bio-assays with two quelites species, Bidens pilosa sens. lat. (Cobblers' pegs) and Lepidium virginicum (Pepper grass) and different cultivars of maize ( Zea mays L.) it could be demonstrated that water extracts of leaves of B. pilosa and L. virginicum cause a significant stimulation of seedling growth of maize. Different cultivars of maize showed no differences in being stimulated by extracts of B. pilosa. This indicates an allelopathic potential of the two tested quelites species.
Extracts of leaves of older plants of B. pilosa (shortly before flowering) do not show this effect. Different water extracts of maize snowed an indifferent influence on germination and seedling growth of B. pilosa and L. virginicum.
Considering these results the practice of the Tarahumara Indians — leaving the quelites a certain amount of time among their maize and harvesting them after that — appears to be a stimulatory method for growing maize. The maize-quelites double-crop system seems to be highly tuned and may be understood as a result of a process of cultural learning among the Tarahumara Indians.     

两种除草剂对云南秋播苦荞田除草效应及其产量的影响

为了探讨除草剂对云南秋播苦荞田的防除效果、苦荞的安全性和产量的影响,以‘云荞1号’为材料,对云南秋播苦荞田进行不除草、人工除草、化学除草(金都尔、乙草胺)苗前土壤喷雾4个处理。试验结果表明,金都尔和乙草胺除草剂对秋播荞麦田的杂草有较好的防除效果,并且金都尔除草剂对阔叶杂草的防除效果大于禾本科杂草的防除效果,而乙草胺除草剂对禾本科杂草的防除效果大于阔叶杂草的防除效果；但两种除草剂对苦荞的出苗和幼苗生长都有一定的抑制作用,并且严重影响苦荞产量。因此在生产中,以阔叶杂草为主的苦荞田建议使用金都尔除草剂、以禾本科杂草为主的苦荞田建议使用乙草胺除草剂,但尚需进一步研究防除效果好又不影响产量的适合苦荞田除草剂浓度的筛选。     

鳢肠水提液对棉花和棉田常见杂草的化感作用

采用培养皿滤纸法研究鳢肠水提液对棉花和棉田常见杂草种子萌发和幼苗生长的化感作用。结果表明:当鳢肠水提液质量浓度为0.01~0.08 g·m L-1时,对中棉所49和中棉所79种子萌发影响不大,而对杂草种子的萌发表现为抑制作用;其中,对禾本科杂草种子萌发的抑制强度表现为牛筋草马唐稗草,对阔叶杂草种子萌发的抑制强度表现为反枝苋马齿苋苘麻。鳢肠水提液对棉花和杂草幼苗生长的影响表现为,低浓度促进,高浓度抑制,并随着质量浓度增加抑制作用提高,其中0.04~0.08 g·m L-1的鳢肠水提液对反枝苋胚根和胚芽长的抑制率均达到100%。     

香蕉茎叶青贮饲料对肉牛育肥效能研究

饲喂效果是评价一种草料应用推广的重要指标。香蕉茎叶作为一种新型非常规饲草料资源，通过与常规饲草料的饲喂比较，明确其饲喂效能为生产应用提供科学依据。连续2 年在不同肉牛养殖场选取18~24 月龄的育肥肉牛，分别进行香蕉茎叶青贮饲料对育肥肉牛增重效果、香蕉茎叶青贮饲料与甘蔗稍叶青贮饲料、玉米秸秆鲜草料、玉米秸秆青贮料、皇竹草鲜草料、带苞全株玉米青贮饲料等不同饲草料对育肥肉牛增重效能的比较试验。于饲喂前和饲喂后的30、60、90、120 天分别对供试牛只进行称重，通过牛只的日增质量评价香蕉茎叶青贮饲料对肉牛的育肥效能。结果表明：香蕉茎叶青贮饲料对西杂牛育肥增重效果明显高于本地黄牛，饲喂西杂牛日增重可达0.92~1.26 kg/头，饲喂本地黄牛日增重为0.41~0.59 kg/头；与其他饲草料饲喂效果相比，香蕉茎叶青贮饲料仅在饲喂30 天的日增质量低于全株玉米青贮饲料0.106 kg/头(P＞0.05)，与玉米秸秆青贮饲料、甘蔗稍叶青贮饲料效果相当(P＞0.05)，略高于玉米秸秆鲜料、皇竹草鲜料饲喂效果(P＞0.05)。香蕉茎叶青贮饲料对育肥肉牛饲喂效果可替代玉米植株、甘蔗稍叶、皇竹草等常规饲草料在肉牛养殖生产中推广应用。     

Modellversuch zur Beschreibung von Konkurrenzvorgängen zwischen Sommerweizen und einer aus Capsella bursa-pastoris L., Stellaria media L. und Alopecurus myosuroides Huds. bestehenden Mischverunkrautung

Investigation to Describe the Competition between Spring Wheat and a Weed Population Consisting of Capsella bursa-pastoris L., Stellaria media L. and Alopecurus myosuroides Huds.
When controlling weeds in cereals using economic threshold as criteria, weed populations must be evaluated for their potential to cause damage at a very early stage. As well as information of actual weed density or weed ground cover, further knowledge about the species specific growth and competition between weed populations is important.
For this purpose the growth and competition between the weeds Capsella bursa-pastoris L., Stellaria media L., Alopecurus myosuroides Huds. and spring wheat ( Triticum aestivum L.) as a model of a typical weed mixture in cereals were studied in a container experiment. The growth with time of individual species was documented using true colour image processing. In that these measurements are non-invasive, the system lends itself specially to time-dependent analyses. The increasing amount of ground covered by leaves between two observation times served as a parameter to evaluate the increase in biomass over this time period and could be used as a evaluation of the competitiveness of the weed species studied.
The results can be summarized as follows: 1) Stellaria media L. proved to be the most competitive of the studied species. 2) The competition to spring wheat from each weed species was similar. 3) A multi species weed population had a tendenci to a lower competitiveness to spring wheat, than a weed population of only-one species.
The importance of this and other similar studies for the improvement for the prediction of economic weed thresholds to estimate weed populations in early stages will be indicated.     

盐胁迫对将军菊苣生长及离子吸收的影响

旨在了解盐胁迫对将军菊苣的生长及Na+、K+、Ca2+吸收和分配的影响。用Hoagland溶液配制不同浓度的NaCl (70、140、210、280 mmol/L)并处理将军菊苣幼苗15天,测定其生物量、生长速率、新生叶参数和矿物质离子。结果表明：与对照组相比,随着盐浓度升高,菊苣生长速率明显减缓(P<0.05);叶长、宽和面积以及鲜重均显著下降,而70 mmol/L组植株根系干重显著增高(P<0.05);处理组根和叶的Na+含量均明显升高而K+含量降低,其中根部显著降低(P<0.05),Ca2+含量变化不明显;根和叶的K+/Na+以及叶的Ca2+/Na+比值均显著降低。这说明盐胁迫造成菊苣植株的离子失衡,促使K+和Ca2+的选择性吸收而耗能,从而使植株生长受到抑制。     

假臭草对南方几种常见大田杂草的化感作用

以假臭草为化感物质供体,飞机草(Eupatorium odoratum L.)、巴西含羞草(Mimosa pudica L.)、稗草(Echinochloa crusgalli (L.)Beauv)、三叶鬼针草(Bidens pilosa L.)和茴麻(Abutilon theophrasti Medic)为受体做生测实验,研究入侵杂草假臭草的鲜样浸提液与干样浸提液的化感作用,为假臭草的绿肥化利用与入侵风险预测提供理论依据。研究结果表明,无论是假臭草鲜样浸提液还是干样浸提液均对供试的几种杂草有明显的抑制作用,并且对幼苗根的抑制作用大于对种子的。在5种供试杂草中,巴西含羞草对假臭草的化感作用耐性最强,飞机草次之。但几种杂草在较高浓度下根全部受到抑制,不能生长。鲜样和干样浸提液强度有一定的差异,但差异不大。因此,将假臭草作为绿肥来防治农田杂草有一定前途,但针对不同的作物系统与主要杂草种类要有广泛的化感研究基础。     

铜胁迫对油麦菜生长和土壤酶活性的影响

在室内进行土培盆栽实验,通过对油麦菜幼苗植株生长、生物量和土壤酶活测定,研究了不同浓度铜胁迫（50,300,500,800,1200,2000 mg/kg干土）对油麦菜幼苗生长和土壤酶 (脲酶、转化酶、酸性磷酸酶、过氧化氢酶) 活性的影响。结果表明：与对照相比,随着铜浓度的增加,油麦菜的叶片受伤率增加,成活率下降,油麦菜鲜重、株高、平均根长亦随 Cu 浓度升高而递减;土壤酶活性随着铜胁迫程度的增加而显著降低,其中脲酶、酸性磷酸酶活性降低最明显。相关分析结果表明,脲酶、转化酶、酸性磷酸酶、过氧化氢酶活性,油麦菜的平均根长、鲜重、株高与土壤铜含量存在着显著或极显著的负相关关系,酶活性与油麦菜的生理指标呈显著或极显著的正相关。可见土壤酶活性可作为检测土壤中重金属污染程度的参考指标之一。     

Die Blattanatomie eines schnell und eines langsam wachsenden Grases in Abhängigkeit von der Stickstoffversorgung

Leaf anatomy of a fast- and a slow-growing grass as dependent on nitrogen supply
The grass species Lolium perenne and Festuca rubra , originating from habitats with differing N-availability, differ in their relative growth rate. This is mainly caused by the higher specific leaf area of L. perenne compared to F. rubra . The leaf anatomy of both species was further investigated. The species were raised in growth chambers under high and low N-supply. The higher specific leaf area of L. perenne (27 mm² mg^–1) in relation to F. rubra (14 mm² mg^–1) was mainly caused by a lower leaf density (0.23 vs. 0.33 mg mm^–3). The level of N-supply influenced both leaf density and leaf thickness. The leaf volume of L. perenne comprised higher fractions of epidermis and lower fractions of mesophyll and intercellular space compared to F. rubra . However, the discrepancy in leaf density between the species could not be explained by anatomical differences. Under low N-supply, the leaves of both species had higher amounts of vascular bundles and fibre cells and lower amounts of intercellular space, which partly explained the higher density of the leaves. It is concluded, that thinner cell walls and higher amounts of cytoplasm cause the higher specific leaf area of L. perenne .     

齿瓣石斛群体性状的变异及主成分分析

探索齿瓣石斛群体变异情况,为生产和育种提供参考。选择齿瓣石斛人工仿野生栽培1~3年的基地6个,每个基地随机选择3个样点,每样点面积2 m2,统计6个主要变异类型的植株数;每个变异类型统计茎长、茎粗、茎节数、单条鲜重、叶长、叶宽、长宽比、叶面积;采用SPSS软件对不同类型齿瓣石斛性状进行差异显著性分析和主成分分析。结果表明齿瓣石斛狭叶粗壮型所占比例最高,血草型最少;铁线草的茎长、茎节数最大,显著高于血草型(P<0.05)和紫鞘粗壮型(P<0.05);宽叶粗壮型的茎粗和单条鲜重均显著高于其他各组(P<0.05);在叶长、叶宽、叶面积上,宽叶粗壮型、狭叶粗壮型、紫鞘粗壮型分列前三位,属于大叶类型,与血草型相比均有显著差异（(P<0.05);齿瓣石斛主要群体性状指标存在不同程度的变异,以单条鲜重和叶面积变异程度最大;在齿瓣石斛育种工作中,可以尝试集中考察能反映齿瓣石斛综合性状的茎长和茎粗这2个植物学性状指标,以提高齿瓣石斛新品种选育的效率。     

生物源除草剂壬酸对非耕地杂草的防治作用

为了了解壬酸制剂对非耕地杂草的防除效果,研究了30%壬酸水乳剂(EW)对非耕地一年生禾本科、阔叶类以及其他类杂草的田间实际防治效果。通过划分小区施药后,调查药后3天,5天和7天的覆盖率防效及7天的鲜重防效。结果表明,供试30%壬酸EW有效成分25~40 kg/hm2（制剂用量83.4~133.3 L/hm2）对各类杂草均有良好的防治效果。施药后7天覆盖度防效及鲜重防效均超过85%,与对照药剂20%百草枯AS有效成分0.45 kg/hm2（使用剂量2.25 L/hm2）差异不明显。其中,30%壬酸EW有效成分40 kg/hm2（制剂用量133.3 L/hm2）对禾本科及阔叶类杂草的覆盖率防效高达94.87%和92.36%,鲜重防效高达95.28%和92.66%。壬酸具有速效性、触杀性和非选择性的作用特点,能够达到生产实践中防除非耕地杂草的要求,值得进一步研究开发。     

江淮地区大麦田除草剂筛选试验

为了筛选江淮地区大麦田有效除草剂,选用麦喜+唑啉草酯处理、高渗异丙隆、麦喜、唑啉草酯进行防除杂草的筛选试验。结果表明,麦喜可以有效防除大麦田阔叶杂草,唑啉草酯可以有效防除禾本科杂草;而以58 g/L麦喜悬浮剂150 mL/hm2+5%唑啉草酯乳油1200 mL/hm2防除阔叶及禾本科杂草总防效较好,60天总草株校正防效、鲜重防效分别达98.58%和98.77%,并且对大麦安全性好,可以在江淮地区大麦田推广应用。     

伴生杂草对小麦化感作用的研究初报

通过用播娘蒿、荠菜、野燕麦、婆婆纳、泽漆5种麦田杂草不同浓度梯度(0.01～0.10gDW/ml)的水提液对小麦进行室内滤纸培养试验,并对小麦的发芽率,根长,苗高,鲜重及干重五项指标进行了全面测试,初步研究了5种麦田杂草对小麦的化感作用。统计结果表明:5种麦田杂草的水提液对小麦的发芽均有明显抑制,其中当浓度为0.10gDW/ml时RI值在-0.516～-0.846之间;而对小麦幼苗的生长影响因种类有差异,其中荠菜、播娘蒿、泽漆对小麦有明显抑制作用,荠菜对小麦苗高的抑制不明显,而对根长、鲜重和干重有明显抑制,最大强度RI值在-0.168～-0.582之间,播娘蒿对小麦苗高的抑制也不明显,而对根长、鲜重和干重有明显抑制,最大强度RI值在-0.170～-0.756之间,泽漆对小麦苗高、根长、鲜重和干重有明显抑制,最大强度RI值在-0.182～-0.779之间;婆婆纳则表现出一定促进作用,尤其对小麦的鲜重和干重的促进作用较明显,最大强度RI在0.012～0.173之间,野燕麦对小麦幼苗影响在供试浓度内不明显。