title: The physiological mechanism of a drooping leaf2 mutation in rice.
abstract: Here we characterized a classic rice (Oryza sativa) drooping leaf2 mutant (named dl2). The dl2 allele affects both the midrib development and the total leaf venation pattern. Leaf anatomy results revealed the central vein lacks both clear cells and the adaxial small vascular bundle in dl2 mutant, which seemed to cause the drooping leaf phenotype. The dl2 leaves contain more small veins, and the size of the vascular cylinder in dl2 leaf is also altered. Furthermore, similar anatomy alteration was found in the dl2 roots. A reduction in the number of xylem and phloem poles in the central vascular cylinder in dl2 roots was observed and the diameter of cortical cell is also reduced. In addition, the alterations of the vegetative development such as the longer leaf blade and fewer adventitious and lateral roots were also observed in dl2. The physiological mechanism underlying the morphological and vascular alterations of dl2 was further studied. The result demonstrated that the dl2 vascular patterning distortions are strictly associated with a defective PAT (polar auxin transport) activity and sensitivity to different classes of polar auxin transport inhibitors. Finally, the drooping leaf phenotype of dl2 is coupled to a defective response to auxin.
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, Chongqing 400044, China. huangjunli@cqu.edu.cn
authors.forename: Junli
authors.initials: J
authors.lastname: Huang
authors.forename: Shugang
authors.initials: S
authors.lastname: Che
authors.forename: Liang
authors.initials: L
authors.lastname: Jin
authors.forename: Feng
authors.initials: F
authors.lastname: Qin
authors.forename: Guixue
authors.initials: G
authors.lastname: Wang
authors.forename: Nana
authors.initials: N
authors.lastname: Ma
mesh_terms: D001692:Biological Transport; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D009154:Mutation; D012275:Oryza / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000502:physiology; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins