马唐和反枝苋对草甘膦的抗药性

旨在明确贵州农田优势杂草马唐和反枝苋对草甘膦的抗药性水平,为杂草的抗性治理提供理论依据.以32个马唐和30个反枝苋的不同种群为研究试材,采用整株盆栽法,施药2周后测定草甘膦对杂草地上部分的鲜重抑制率.结果表明:毕节七星关区六合村马唐种群敏感性最低,ED50值为16.23 g a.i/hm2,其他种群相对抗性倍数在1.0...     

玉米田杂草反枝苋对莠去津的敏感性试验研究

用不同剂量的莠去津对采自东北地区的反枝苋(Amaranthus retroflexus L.)进行田间喷雾处理。试验结果表明:采自不同地区玉米田的反枝苋对莠去津表现了不同的敏感性,采自熊岳、沈阳、铁岭、昌图、丹东、鞍山等地区的相对抗药性倍数低于2,而采自兴城、大连两地的反枝苋与采自其他地区的比较相对抗性水平较高,相对抗药性倍数分别为3.49、2.56。     

角茴香根和地上部水浸液对杂草反枝苋的化感作用

以常见杂草反枝苋为受体植物,采用培养皿滤纸法,通过测定角茴香根水浸液和地上部水浸液对杂草反枝苋的种子萌发和幼苗生长的影响。结果表明:不同浓度的角茴香根和地上部水浸液均对反枝苋种子的萌发和幼苗的根长产生了明显的抑制作用,且随着浓度的增加抑制作用增强,当各水浸液的浓度大于0.030 g.mL-1时,即可对反枝苋种子72 h萌发的抑制率达到50%以上;当各水浸液处理浓度大于0.010 g.mL-1时,反枝苋幼苗的根长便低于对照的50%。角茴香根水浸液对反枝苋幼苗的下胚轴产生低促高抑的浓度双重效应,当根水浸液浓度小于0.030 g.mL-1时,促进反枝苋下胚轴的生长;当根水浸液浓度大于0.030 g.mL-1时,抑制反枝苋下胚轴的生长。研究发现,角茴香根和地上部水浸液均对反枝苋表现出明显的化感作用。     

叉枝鸦不同溶剂萃取物对反枝苋种子萌发及幼苗生长的影响

为了确定沙漠野生植物叉枝鸦葱拟化感物质的有效部位,为分离纯化拟化感先导化合物奠定基础,试验研究了叉枝鸦葱醇提物的四种不同极性溶剂萃取物对反枝苋种子萌发、幼苗生长发育的影响.采用培养皿法,在人工气候箱模拟条件下,测定各萃取物对反枝苋种子萌发、幼苗生长发育的影响.结果表明各萃取物对反枝苋种子萌发、幼苗生长发育均有不同程度的...     

反枝苋水提液对不同杂草化感作用研究

以反枝苋水提液为化感研究对象,分别以狗尾草、藜、马齿苋、龙葵为受体植物。通过试验可以得出,当反枝苋水提液浓度在0.001~0.1克/毫升时,对狗尾草的萌发及幼苗均无明显抑制作用;当反枝苋水提液浓度在0.001~0.1克/毫升时,对藜、马齿苋、龙葵萌发及幼苗有抑制作用,抑制效果随着水提液浓度的增加而增加,各处理间差异显著。     

大花金鸡菊不同器官除草活性的研究

为了明确大花金鸡菊不同器官的除草活性,给进一步开展活性化合物的研究提供依据,以生菜、反枝苋、苘麻、小麦和稗草为受体植物,采用琼脂混粉法进行了室内除草活性的测定.结果表明,大花金鸡菊的不同器官粉末在10 g·L-1的添加浓度下对各受体植物幼苗的生长均具有明显的抑制作用.对生菜、反枝苋和苘麻3种双子叶植物所表现出的抑制效果要高于对小麦和稗草2种单子叶植物的抑制效果.各器官之间除了对小麦幼苗和反枝苋胚轴的生长表现出明显的抑制差异外,对其余受体植物胚根和胚轴的抑制效果之间多数差异不大.     

渭河阶地不同生境反枝苋种子萌发的热量需求研究

为研究反枝苋对气候变暖的响应，预测其萌发时间，为适时防控提供科学依据，以陕西杨凌渭河三道塬的反枝苋种子为材料，利用积温模型定量估计种子萌发的热量需求，计算其萌发的基础温度（T_b）、调整累积萌发率达到50%所需积温［θ_T(50)］及积温标准差（σ_θT）等参数。结果表明，不同生境条件的反枝苋种子质量及上述积温模型参数存在显著差异。头道塬、二道塬和河滩地的反枝苋种子千粒质量为0.322 5、0.311 7和0.348 5 g ，头道塬、二道塬反枝苋种子萌发的T_b为13.98和23.14 ℃，θ_T(50)为398.74和326.79 ℃·h，σ_θT为64.70和149.03 ℃·h。表明相对于低海拔地点，高海拔处的反枝苋具有萌发基础温度低，萌发热量需求高、变幅小的特点。这种差异反映出反枝苋对环境的强适应性。在全球气候变暖的条件，反枝苋的防控难度将增加。根据陕西杨凌地区多年的气象数据预测2020年渭河头道塬、二道塬反枝苋的萌发日期分别为4月18日和6月6日前后，萌发后1周为防控反枝苋的适宜期。     

反枝苋对棉花的密度竞争作用

【目的】反枝苋是世界性恶性杂草之一,为安徽省沿江棉区主要杂草,而棉花对杂草竞争十分敏感。论文旨在明确反枝苋对棉花的密度竞争影响,为棉田杂草反枝苋的综合防治提供理论依据。【方法】2013—2015年在安徽省安庆市试验地,采用添加系列试验方法,棉花密度保持不变,设置8个反枝苋密度(0、0.125、0.25、0.5、1、2、4、8株/m)与棉花全生育期竞争,研究不同反枝苋密度竞争对棉花生长、子棉产量及其构成因素、纤维品质的影响。【结果】随着反枝苋密度增加,反枝苋株高、茎直径逐渐减小;相对于0.125株/m的反枝苋,反枝苋茎直径分别于1株/m(2013年和2014年)、0.5株/m(2015年)显著降低12.0%—18.6%;反枝苋株高则在2015年于0.5株/m显著减少24.2%。3年数据平均,单位面积反枝苋生物量由1 156.9 kg·hm-2(0.125株/m)逐渐增加到7 524.0 kg·hm-2(8株/m),较高密度反枝苋种内竞争明显。随着反枝苋与棉花竞争时间的延长,反枝苋株高于52—83 DAE(出苗后天数,days after emergence)逐渐超过棉花的,茎直径于18—70 DAE逐渐大于棉花的。在棉花成熟期,反枝苋株高比棉花高35.6—128.2 cm,反枝苋茎直径比棉花粗9.9—24.8 mm。反枝苋在株高和生物量上对棉花具明显优势。随着反枝苋密度增加,棉花株高变化不明显,茎直径明显减小;棉花单株铃数、果枝数和单铃重显著减少,衣分也有一定程度减小。1株/m的杂草密度导致棉花单株果枝数减少4.63%—69.18%,铃数减少20.81%—84.98%,单铃重减少3.04%—20.36%,衣分减少1.54%左右。引起子棉产量显著减产的反枝苋密度分别是0.125株/m(2013年)和0.25株/m(2014年和2015年),导致子棉减产14.0%—33.7%;子棉产量损失率与反枝苋密度符合双曲线模型,据此可预测子棉减产50%的反枝苋密度为0.2—2.8株/m。在反枝苋与棉花竞争91 DAE,0.125—0.5株/m反枝苋可显著减少棉花单株果枝数和铃数。在部分年份,棉纤维的上半部平均长度、马克隆值及断裂比强度随反枝苋密度增加有减小的趋势,且差异显著。【结论】在安徽省沿江棉区,当反枝苋与棉花全生育期竞争时,对反枝苋及棉花的株高影响不明显,对两者的茎直径产生显著影响;随着竞争时间的延长,反枝苋的株高和茎直径逐渐大于棉花的;因而反枝苋在株高和生物量上对棉花具有竞争优势。反枝苋苗期是其防治关键期。当反枝苋密度逐渐增加时,其种内竞争逐渐增强。反枝苋生物量易受环境条件影响,随着反枝苋密度增加,单位面积反枝苋生物量增加,对棉花生长和产量的抑制作用明显增强。反枝苋竞争主要通过影响棉花单株铃数和单铃重而减少棉花产量。推测本地区导致子棉减产5%的反枝苋密度为0.011—0.090株/m。     

3种杂草种子对紫花苜蓿种子化感作用的研究

为研究杂草种子对紫花苜蓿种子萌发的影响,用藜、反枝苋、骆驼蓬3种杂草种子与紫花苜蓿种子按比例进行混合发芽试验,分析紫花苜蓿的发芽率、根长和芽长,研究藜、反枝苋、骆驼蓬对苜蓿种子萌发和幼苗生长中的影响.结果表明,藜种子和紫花苜蓿种子混播使紫花苜蓿种子发芽率提高,藜与苜蓿种子10∶50混播处理与对照组有显著差异(P＜0.05).根长与对照组均有显著差异(P＜0.05),藜种子对苜蓿根长和芽长总体呈现抑制趋势;反枝苋与紫花苜蓿种子混播后紫花苜蓿的发芽率与对照均有显著差异(P＜0.05),随着反枝苋种子密度的增加,紫花苜蓿种子发芽率除反枝苋与苜蓿10∶50混播处理外均有升高的趋势.根长与对照相比均表现出增长的趋势,反枝苋与苜蓿种子混播比例为40∶50、50∶50时与其他处理差异显著(P＜0.05).对芽长的影响总体上呈现抑制趋势;骆驼蓬与紫花苜蓿种子混播后紫花苜蓿种子发芽率均低于对照,骆驼蓬与紫花苜蓿混播比例为30∶50、40∶50时与其他处理和对照差异显著(P＜0.05),根长、芽长均比对照有所减小.骆驼蓬与紫花苜蓿种子混播比例为50∶50时,发生死亡.     

葎草不同器官化感活性的研究

以生菜、反枝苋、苘麻、小麦和稗草为指示植物,采用琼脂混粉法对葎草不同器官的化感活性进行了测定。研究表明,葎草的不同器官粉末在10 g/L的添加浓度下对各指示植物幼苗的生长均具有不同程度的抑制作用,且对生菜、反枝苋和苘麻3种双子叶植物的抑制效果高于对小麦和稗草2种单子叶植物的抑制效果,其中以叶器官的抑制活性最高。     

Effects of Methylated Soybean Oil Adjuvant on Fomesafen Efficacy to Weeds

Tank-mix adjuvant has the potential to improve the weed control efficacy of post-emergence herbicides. In order to study the synergistic effect of adjuvant, the effects of different rates of fomesafen alone or applied methylated soybean oil adjuvant（MSO） were sprayed on redroot pigweed, abutilon and black nightshade under greenhouse condition. The results showed that fomesafen had different performance on the three weeds, and MSO adjuvant could effectively increase the control. The nightshade control was lower than other two weeds with all the fomesafen doses from 131.25 to 506.25 ga.i. · hm-2 with or without adjuvant. The control of abutilon was between the black nightshade and the redroot pigweed, and had better control at 375 ga.i. · hm-2 with adjuvant or 506.25 ga.i. · hm-2 alone or with adjuvant respectively. The results indicated that mixing adjuvant with fomesafen improved the control on weeds, especially at the low rate. Black nightshade was more difficult to control. The redroot pigweed had the most susceptibility to fomesafen alone or with adjuvant.     

Plant species identification using Elliptic Fourier leaf shape analysis

Elliptic Fourier (EF) and discriminant analyses were used to identify young soybean (Glycine max (L.) merrill), sunflower (Helianthus pumilus), redroot pigweed (Amaranthus retroflexus) and velvetleaf (Abutilon theophrasti Medicus) plants, based on leaf shape. Chain encoded, Elliptic Fourier harmonic functions were generated based on leaf boundary. A complexity index of the leaf shape was computed using the variation between consecutive EF functions. Principle component analysis was used to select the Fourier coefficients with the best discriminatory power. Canonical discriminant analysis was used to develop species identification models based on leaf shapes extracted from plant color images during the second and third weeks after germination. The classification results showed that plant species during the third week were successfully identified with an average of correct classification rate of 89.4%. The discriminant model correctly classified on average: 77.9% of redroot pigweed, 93.8% of sunflower, 89.4% of velvetleaf and 96.5% of soybean. Using all of the leaves extracted from the second and the third weeks, the overall classification accuracy was 89.2%. The discriminant model correctly classified 76.4% of redroot pigweed, 93.6% of sunflower, 81.6% of velvetleaf, 91.5% of soybean leaf extracted from trifoliolate and 90.9% of soybean unifoliolate leaves. The Elliptic Fourier shape feature analysis could be an important and accurate tool for weed species identification and mapping.     

安徽省沿江棉区两种栽培方式下棉田杂草发生与危害研究

初步研究了安徽省沿江棉区直播棉田和移栽棉田杂草发生和危害。运用杂草群落的重要值(MDK)和相对多度(RA),结合K类中心聚类法分析两种模式棉田杂草发生和危害程度。在直播棉田和移栽棉田中,杂草发生种类和杂草演替规律差异不大。一般是以禾本科杂草牛筋草、马唐为重要杂草,由铁苋菜、狗尾草、马齿苋、通泉草、反枝苋和异型莎草等主要杂草组成的杂草群落;直播棉田杂草在棉花蕾期发生密度较大,对棉花的危害程度也较大。两种栽培方式下,不除草棉田的棉花前期株高、叶片数、果枝数和果节数显著低于常规除草棉田;后期的株高、单株铃数、单铃重显著低于常规除草棉田,皮棉产量减少极显著。     

Hyperspectral species mapping for automatic weed control in tomato under thermal environmental stress

This work studied the impacts of variations in environmental temperature on hyperspectral imaging features in the visible and near infrared regions for robust species identification for weed mapping in tomato production. Six major Californian processing tomato cultivars, black nightshade (Solanum nigrum L.) and redroot pigweed (Amaranthus retroflexus L.) were grown under a variety of diurnal temperature ranges simulating conditions common in the Californian springtime planting period and one additional treatment simulating greenhouse growing conditions. The principal change in canopy reflectance with varying temperature occurred in the 480-670 and 720-810 nm regions. The overall classification rate ranged from 62.5% to 91.6% when classifiers trained under single temperatures were applied to plants grown at different temperatures. Eliminating the 480-670 nm region from the classifier’s feature set mitigated the temperature effect by stabilizing the total crop vs. weed classification rate at 86.4% over the temperature ranges. A site-specific recalibration method was also successful in alleviating the bias created by calibrating the models on the extreme temperatures and increased the classification accuracy to 90.3%. A global calibration method, incorporating all four temperature conditions in the classifier feature space, provided the best average total classification accuracy of 92.2% out of the methods studied, and was fairly robust to the varying diurnal temperature conditions.     

几种藜科杂草化感作用的初步测定

[目的]研究藜科杂草提取物的除草、抑菌功能。[方法]以反枝苋为供试杂草,以黄瓜枯萎病菌、苹果腐烂病菌和小麦纹枯病菌为供试菌种,研究藜科杂草猪毛菜、灰藜、小藜、绿藜、地肤的茎叶提取物对杂草和病菌的抑制作用。[结果]5种杂草的茎叶提取物对反枝苋种子萌发及幼苗生长都有一定的抑制作用,其中,地肤茎叶提取物的抑制活性最高,当其浸膏浓度为0.10 g/ml时,对反枝苋茎生长的抑制率达100%,对种子萌发和根生长的抑制率超过90%;用石油醚、乙酸乙酯、甲醇对地肤茎叶提取物萃取分离后发现,石油醚萃取部分的除草效果较好,而甲醇萃取部分的抑菌活性较高。[结论]藜科杂草提取物具有一定的除草和抑菌功能。     

豆磺隆对耐性甜菜生物性状的影响

利用已经筛选的耐豆磺隆甜菜品系,研究豆磺隆土壤和茎叶处理对甜菜生物性状的影响。结果表明,土壤中豆磺隆施用量为0.5 ga.i..hm-2时对耐性甜菜品系生长无明显抑制作用。当土壤中豆磺隆施用量为0.5和1.0ga.i..hm-2时,耐性甜菜品系根系活力降幅较小,叶绿素含量呈增加趋势。用7.5 ga.i..hm-2豆磺隆茎叶处理3 d后,耐性甜菜品系叶绿素含量开始增加,并且在短时间内恢复至正常水平,叶片鲜重虽然受到一定抑制,但6 d后开始恢复生长,根系则保持持续增重。     

甜菜耐氯嘧磺隆生化机理的研究

 【目的】对甜菜耐氯嘧磺隆生化机理进行研究,为甜菜耐氯嘧磺隆基因型的合理应用提供理论依据。【方法】以耐性甜菜为试验材料,采用田间框栽和水培试验相结合的方法,对甜菜在氯嘧磺隆胁迫下的生化机理进行研究。【结果】土壤中氯嘧磺隆0.5～1.5ga.i.ha-1剂量下,耐性甜菜品系叶片中GST活性明显增加,根中GSH含量较对照增加50.0～490.1 μg?g-1。敏感甜菜在氯嘧磺隆用量为0.5ga.i.ha-1时,叶片中GST活性略有增加,但较耐性甜菜低122.6U?(min?mgprotein)-1,根中GSH含量与对照相比仅增加7.4 μg?g-1。氯嘧磺隆0.5 ga.i.hm-2施用剂量下,耐性甜菜苗期和叶丛形成期ALS活力与对照相比分别增加62.5％和70.6％,而此时敏感甜菜品系ALS活力与对照相比则分别降低36.8%和64.8％。【结论】耐性甜菜GST、GSH活性及氯嘧磺隆作用靶酶ALS活力在氯嘧磺隆施用后短时间内快速升高是甜菜对氯嘧磺隆耐性增强的重要原因。     

生物肥和氯嘧磺隆对水稻土壤微生物和土壤酶活性的影响

采用盆栽试验,研究了三种不同生物肥在不同浓度氯嘧磺隆胁迫下对水稻微生物数量和土壤酶活性的影响。结果表明,在水稻拔节期,供试三种生物肥在不同浓度氯嘧磺隆胁迫下均可提高土壤细菌数量,生物肥Ⅰ可提高土壤放线菌数量,生物肥Ⅱ在低浓度氯嘧磺隆胁迫下,土壤放线菌数量与CK无差别,高浓度氯嘧磺隆（3μg.kg-1）胁迫下,可提高土壤放线菌数量。生物肥Ⅲ在施用0.3μg.kg-1氯嘧磺隆时可提高土壤放线菌数量,而氯磺隆常规浓度胁迫下,显著降低土壤放线菌数量。在水稻成熟期,生物肥Ⅰ低浓度氯嘧磺隆胁迫下对水稻细菌、放线菌和真菌数量无影响,高浓度氯嘧磺隆胁迫下土壤三种微生物数量减少。生物肥Ⅱ在低浓度氯嘧磺隆胁迫下对三种微生物数量无影响,高浓度氯嘧磺隆胁迫下可使土壤微生物数量增加。生物肥Ⅲ在不同浓度氯嘧磺隆胁迫下对细菌数量影响不明显,高浓度氯磺隆胁迫下,显著降低土壤放线菌数量。供试三种生物肥在不同浓度氯嘧磺隆胁迫下均可提高土壤脲酶活性。生物肥Ⅱ解药害能力弱其他两种生物肥较好,有待于田间试验进一步验证。     

Effect of Chlorimuron-Ethyl on Biochemical Mechanism in Tolerant Sugar Beet

Effect of chlorimuron-ethyl on biochemical mechanism in tolerant sugar beet was investigated to provide basic data on using the tolerant genotype properly. Tolerant sugar beet was used to analyze its biochemical mechanism under chlorimuron- ethyl stress with frame culture in field and water culture. Glutathione S-transferase （GST） activity of leaves in tolerant sugar beet was remarkably increased as chlorimuron-ethyl was preemergence applicated at 0.5 and 1.5 g a.i. hw1, at the same time glutathione （GSH） content increased 50.0-490.1 p.g g-~. GST activity of sensitive sugar beet decreased 122.6 U mg-~ min-1 compared with tolerant sugar beet and GSH content only increased to 7.4 p.g g-~ at chlorimuron-ethyl 0.5 g a.i. ha-~ in sensitive sugar beet. The higher GST activity and GSH content conjugated chlorimuron-ethyl absorbed in tolerant sugar beet and made it lost activity. Acetolactate synthases （ALS） activity of the tolerant sugar beet increased to 62.5 and 70.6%, respectively in seedling and leaf growth period, at the same time ALS activity of the sensitive variety was decreased to 36.8 and 64.8%, respectively. The rapidly increased GST activity, GSH content, and ALS, the target enzyme activity were the important pathways for enduring chlorimuron-ethyl in tolerant sugar beet.     

阿城地区大豆田除草剂残留空间分布研究

采用超高效液相色谱串联质谱法测定黑龙江省阿城地区典型耕地的大豆田中0~45 cm 不同土层豆乙合剂（乙草胺、氯嘧磺隆）中两种除草剂的残留量,研究其空间分布特征。样品经 乙腈提取,QUECHERS 法净化,测得三种除草剂的空间残留量,结果表明:（1）在各采集点土壤 中两种除草剂都有残留,乙草胺残留范围为9.16 ~ 96.26 ng/mL;氯嘧磺隆为2021.67 ~ 465287 ng/mL。并且,氯嘧磺隆的残留量明显大于乙草胺的残留量。（2）从检出的两种除草剂残留量的 垂直空间分布可知,乙草胺和氯嘧磺隆在土层中残留量的空间分布总体均呈先上升后下降的趋 势。