杂草学第二章02.pdf

姜临建姜临建2013.10.232013.10.23Knowing WeedsKnowing WeedsWhat is lifehttp:/ Categorization According to habitat1.Terrestrial (陆生)2.Aquatic(水生)According to life cycleAnnuals(一年生杂草)Biennials（两年生杂草）Perennials（多年生杂草）Annuals(一年生杂草)：Summer annualsWinter annualspigweed 苋菜Lambsquarters藜purslane 马齿苋Crabgrass 马唐狗尾草foxtail What crops will suffer summer annual weed problems?winter annuals:播娘蒿 Flixweed荠菜 Shepherds Pursewild oat 野燕麦雀麦 brome grass节节麦 goatgrassBiennials（两年生杂草）野胡萝卜 Wild CarrotPerennials（多年生杂草）Quackgrass 匍匐冰草Dandelion 蒲公英 耕作制度是否会影响杂草？According to morphologyMonocots（单子叶杂草）:seedlings bear only one cotyledon(seed leaf)Grasses(禾本科)Sedges（莎草）Dicots（双子叶杂草）阔叶杂草Discribe a weed 一年生单子叶杂草 多年生禾本科杂草 一年生双子叶杂草 多年生双子叶杂草 莎草 Invasive(入侵)vs Native（本地）Parasitic vs non-parasitic紫茎泽兰 http:/ of Weed Propagation(reproduction)有性生殖（Sexual reproduction）无性生殖（Asexual reproduction）有性生殖（Sexual reproduction）Cross Pollination野油菜 Self Pollination无性生殖（Asexual reproduction）1.Rhizome（根茎）:A horizontal,underground stemwhich can produce adventitious roots and shoots(i.e.,new plants)at the nodes.2.Stolon（匍匐茎）:An above-groundstem that grows flat on the ground and can produce adventitious roots and shoots(i.e.,new plants)at the nodes.狗牙根Bermudagrass 3.Tuber（块茎）:Enlarged terminal portions of rhizomes.莎草Sedges 4.Bulb（鳞茎）:Specialized underground storage organ consisting of fleshy leaves with a short stem at the base.Wild garlic 蓟5.Creeping roots（匍匐根）:Horizontal rootsmodified for food storage and vegetative reproduction(can give rise to shoots).Often deep in the soil.许多杂草，尤其是恶性杂草1.通常具有有性和无性两种方式2.种子和无性繁殖体对除草剂的敏感性不同莎草III.Methods of Weed Dissemination(spread):Natural dispersal Artificial dispersalNatural dispersal a.Wind(蒲公英)b.Water c.Animals(苍耳)d.Forceful dehiscence（酢浆草Oxalis）Artificial dispersal Contaminated seeds Machinery ManureCertified SeedsSeed Germination and DormancySeed Germination requirement1.water2.temperature3.oxygen4.light5.germination stimulate(striga)Seed DormancyViable Seeds that do not germinate under favorable environmental conditions.Why?Impermeable seed coat(velvetleaf 苘麻)Hard seed coat（pigweed 苋菜）Immature embryo（smartweed 蓼科）Hormonal imbalance Results of Dormancy120-year seed bury experiment When:1879 Who:Dr.William James Beal,Where:Michigan Agricultural College in East Lansing,Michigan,USA What:buried seeds in soil How:seeds in a bottle,filled with sand and upside down2002 年 Frank W.Telewski and Jan ZeevaartSoil seed bank本节要点 了解杂草的一般分类 了解杂草的繁殖及传播方式 了解杂草种子休眠的意义