title: Initiation and elongation of lateral roots in Lactuca sativa.
abstract: Lactuca sativa cv. Baijianye seedlings do not normally produce lateral roots, but removal of the root tip or application of auxin, especially indole-butyric acid, triggered the formation of lateral roots. Primordia initiated within 9 h and were fully developed after 24 h by activating the pericycle cells opposite the xylem pole. The pericycle cells divided asymmetrically into short and long cells. The short cells divided further to form primordia. The effect of root tip removal and auxin application was reversed by 6-benzylaminopurine at concentrations >10(-8) M. The cytokinin oxidase inhibitor N1-(2chloro4pyridyl)-N2-phenylurea also suppressed auxin-induced lateral rooting. The elongation of primary roots was promoted by L-alpha-(2-aminoethoxyvinyl) glycine and silver ions, but only the latter enhanced elongation of lateral roots. The data indicate that the induction of lateral roots is controlled by basipetally moving cytokinin and acropetally moving auxin. Lateral roots appear to not produce ethylene.
authors.affiliation: Department of Biology, University of Southwestern Louisiana, Lafayette 70504-2451, USA.
authors.forename: N
authors.initials: N
authors.lastname: Zhang
authors.forename: K H
authors.initials: KH
authors.lastname: Hasenstein
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000613:Aminobutyrates / Q000494:pharmacology; D001593:Benzyl Compounds; D003583:Cytokinins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005030:Ethylenes / Q000378:metabolism; D005875:Gibberellins / Q000494:pharmacology; D006540:Herbicides / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology; D007701:Kinetin; D018545:Lactuca / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D010671:Phenylurea Compounds / Q000494:pharmacology; D010797:Phthalimides / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D011687:Purines; D011725:Pyridines / Q000494:pharmacology; D012835:Silver Nitrate / Q000494:pharmacology
chemical_list: D000613:Aminobutyrates; D001593:Benzyl Compounds; D003583:Cytokinins; D005030:Ethylenes; D005875:Gibberellins; D006540:Herbicides; D007210:Indoleacetic Acids; D007211:Indoles; D010671:Phenylurea Compounds; D010797:Phthalimides; D010937:Plant Growth Regulators; D011687:Purines; D011725:Pyridines; C014612:indolebutyric acid; C002687:alpha-naphthylphthalamic acid; C012175:2-amino-4-(2-aminoethoxy)butanoic acid; C030737:indoleacetic acid; C036216:ethylene; D012835:Silver Nitrate; C007842:gibberellic acid; D000225:Adenine; C116093:N-(2-chloro-4-pyridyl)-N'-phenylurea; C480551:benzylaminopurine; D007701:Kinetin