麦类作物化感作用种质资源筛选与评价

以来自国内外的289份大麦品种和90份小麦品种为材料,进行室内化感潜力评价和田间试验考察其抗草性能,结果表明,供试大麦材料中有36个品种（占总数12.5%）显示出较强的化感作用潜力;22个品种（占总数的7.9%）显示较弱或无化感作用潜力.54个田间抗草性能较好的大麦品种中37个品种在室内化感潜力评价中对莴苣根长的抑制率（inhibitoryrate,IR）〉50%.从供试小麦材料中筛选出5个特强化感潜力品种,分别为81-214、115/青海麦、百泉3199、92L89和92H31,对莴苣根长的IR依次为69.1%、68.5%、68.7%、69.1%和65.2%;13个品种（占总数的14.4%）显示出较弱或无化感作用潜力.抗草性能较强的36个小麦品种中,有13个品种室内对莴苣IR≥50%.大麦、小麦品种间都存在化感作用潜力的基因型差异,且其化感作用特性会受环境因素的影响.     

空心莲子草浸提液对3种蔬菜种子萌发的化感效应

空心莲子草Alteranthera philoxeroides Griseb又名喜旱莲子草、水花生,是苋科莲子草属的多年生宿根草本植物.空心莲子草是入侵破坏性很强的植物种,生长速度和对环境的适应性均超过一般作物.其以根茎进行营养繁殖,匍匐茎发达,并于节处生根,茎的节段亦可萌生成株,借以蔓延及扩散[1-3].有些外来植物可分泌对其他植物有抑制作用的化感物质等来排斥其他物种[4].空心莲子草进入一个新的领域后,往往具有很强的竞争能力,这种竞争能力是否与该植物对周围杂草、农作物也产生化感效应有关,目前仅有少量报道[5-8].对空心莲子草的研究目前主要集中在其生物学特征、防除和对环境中重金属的处理[9-15]等方面,而对其化感作用的研究较少见.     

植物化感作用研究进展

对植物化感作用物质及其作用机制,以及化感与可持续农林生产、生态系统的关系进行了综述,并提出了化感作用研究的发展前景。     

银合欢落叶层对苗圃生长的森林一农田作物的他感作用(英文)

利用随机区组试验评估了孟加拉国吉大港大学苗圃内的银合欢落叶对森林作物种白格、黄金檀和农田作物种长豇豆、鹰嘴豆和木豆的他感作用。结果表明,凋落叶诱导抑制作物的萌发和生长,该抑制作用依赖于萃取物浓度、凋落物及受体物种类型。萃取物浓度越高则他感作用越强。受体植物的生长响应随应用的凋落叶而变化。低浓度(10g·m-2)凋落叶对农田作物嫩芽生长有促进作用,而其他浓度的凋落叶则呈现明显的抑制作用,施用的凋落叶浓度越大抑制作用也越大。但是不同处理所表现出的抑制趋势并不均一,根系生长受到的影响大于嫩芽。图3表4参34。     

辣椒根系分泌物的化感作用及其化感物质分析

 利用生物测定和GC-MS分析的方法，研究了辣椒根系分泌物各组分的化感作用及其优势组分的化感物质。结果表明：辣椒根系分泌物各组分对莴苣的化感作用不同，以乙醚洗脱组分的化感作用最强；对乙醚洗脱组分进行再分离，最后得出80%乙醚＋20％乙酸乙酯洗脱组分的化感作用最强；对80%乙醚＋20％乙酸乙酯洗脱组分进行GC-MS分析鉴定，确定辣椒根系分泌的主要化感物质为邻苯二甲酸二丁酯、邻苯二甲酸-丁基-环己烷基酯、邻苯二甲酸-丁基-异丁酯、邻苯二甲酸二叔丁酯、二苯胺、4,4’-叔丁基二苯酚、苯萘胺、邻苯二甲酸，其中，邻苯二甲酸二丁酯的含量最高。     

Root exudation of diclofop-methyl and triasulfuron from foliar-treated durum wheat and ryegrass

In this study, we evaluated the release of diclofop-methyl and triasulfuron from the roots of foliar-treated ryegrass and wheat. The study with ¹⁴C-diclofop-methyl indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass. No root exudation from ¹⁴C-diclofop-methyl-treated wheat plants was observed, while 20 days after treatment (DAT) 0.2–0.9% of radioactivity absorbed by ryegrass was found exuded in the growing medium. Root exudation was stimulated three to six times by the presence of untreated wheat or ryegrass sharing the growing medium with diclofop-methyl-treated ryegrass. No subsequent uptake of exuded radiolabel by untreated plants (ryegrass or wheat) in the same pot with ¹⁴C-diclofop-methyl-treated ryegrass was observed. The study with ¹⁴C-triasulfuron indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass and also into the growing medium. By 20 DAT, 0.5–4.2% of radioactivity absorbed by wheat or ryegrass was found exuded in the growing medium. The presence of untreated plants (wheat or ryegrass) in the same pot as triasulfuron-treated ryegrass or wheat induced exudation seven to 32 times more. The study also revealed a subsequent uptake of exuded compounds by untreated wheat or ryegrass sharing the medium of ¹⁴C-triasulfuron-treated plants. This study has demonstrated for the first time that the root exudation of exogenous compounds can be related to plant arrangement in pots. The implication is that herbicide root exudation and transfer, a form of allelopathy, could be significant in the field. A precise estimation of environmental fate, unexpected ecological side effects and residual activity of herbicides may require quantification of such exudation.     

The Exploitation of Crop Allelopathy in Sustainable Agricultural Production

Crop allelopathy may be useful to minimize serious problems in the present agricultural production such as environmental pollution, unsafe products, human health concerns, depletion of crop diversity, soil sickness and reduction of crop productivity. Several crops including alfalfa, buckwheat, maize, rice, rye, sorghum, sunflower, wheat, etc. are affected either by their own toxicity or phytotoxin exudates when their residues decompose in the soil, that show strong suppression on weed emergences. Allelopathic crops when used as cover crop, mulch, smother crops, green manures, or grown in rotational sequences are helpful in reducing noxious weeds and plant pathogen, improve soil quality and crop yield. Those crop plants, particularly the legumes, incorporated at 1–2 tons ha⁻¹ (alfalfa, buckwheat, rice by-products), which can give weed reduction and increase of rice yield by 70 and 20 %, respectively, are suggested for use as natural herbicides. Allelochemicals from allelopathic crops may aid in the development of biological herbicides and pesticides. Cultivating a system with allelopathic crops plays an important role in the establishment of sustainable agriculture. The introduction of allelopathic traits from accessions with strong allelopathic potential to the target crops will enhance the efficacy of crop allelopathy in future agricultural production.     

几种观赏型沉水植物对富营养化蓝绿藻类的抑制作用

一些大型沉水植物种类的存在对“水华”藻类的生长具有抑制作用,其主要机制是水生高等植物不仅与藻类竞争营养、光照和生长空间等生态资源,而且还可以向水中分泌具有抑制藻类生长的化感物质。通过连续滴加种植水的方式研究了3种观赏型沉水植物矮慈菇（Sagittaria pygmaea Miq）、杉叶藻（Hippuris vulgaris.）、石龙尾（Limnophila heterophylla）对5种富营养化淡水藻,蓝藻：铜绿微囊藻（Microcystis aerugnasa）、纤维席藻（Phormidium tenue）;绿藻：衣藻（Chlamy domonas sajao）、四尾栅藻（Scenedesmus quaclricauda）、小球藻（Chlorella pyrenoidosa）的抑制作用。研究结果表明：（1）矮慈菇种植水对铜绿微囊藻、四尾栅藻、纤维席藻的生长没有影响,对小球藻的生长具有促进作用,对衣藻的生长具有明显的抑制作用;（2）杉叶藻种植水小球藻、衣藻和纤维席藻的生长没有影响,对四尾栅藻的生长具有促进作用,对铜绿微囊藻生长具有明显的抑制作用;（3）石龙尾种植水对小球藻、四尾栅藻、纤维席藻都具有明显的抑制作用,对铜绿微囊藻的生长没有影响,对衣藻的生长具有促进作用。3种沉水植物中,石龙尾的抑藻能力最强,矮慈菇和杉叶藻次之,石龙尾的化感抑藻效应更具有广谱性,在富营养化水体中与蓝绿藻类的竞争更具有优势,比较适用于改善城市景观水体水环境质量。