title: Cytochalasin D does not inhibit gravitropism in roots.
abstract: It is generally thought that sedimenting plastids are responsible for gravity sensing in higher plants. We directly tested the model generated by the current statolith hypothesis that the gravity sensing that leads to gravitropism results from an interaction between the plastids and actin microfilaments. We find that the primary roots of rice, corn, and cress undergo normal gravitropism and growth even when exposed to cytochalasin D, a disruptor of actin microfilaments. These results indicate that an interaction between amyloplasts and the actin cytoskeleton is not critical for gravity sensing in higher plants and weaken the current statolith hypothesis.
authors.affiliation: Section of Plant Biology, Cornell University, Ithaca, New York 14853, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Staves
authors.forename: R
authors.initials: R
authors.lastname: Wayne
authors.forename: A C
authors.initials: AC
authors.lastname: Leopold
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects* / Q000502:physiology; D000199:Actins / Q000037:antagonists & inhibitors* / Q000502:physiology; D019607:Brassicaceae / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D016764:Cell Polarity; D015638:Cytochalasin D / Q000494:pharmacology*; D003595:Cytoplasmic Streaming; D003599:Cytoskeleton / Q000187:drug effects / Q000502:physiology; D018522:Gravitropism / Q000187:drug effects* / Q000502:physiology; D018466:Gravity Sensing / Q000187:drug effects / Q000502:physiology*; D012275:Oryza / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D018518:Plant Root Cap / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D018087:Plastids / Q000502:physiology*; D013997:Time Factors; D003313:Zea mays / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure
chemical_list: D000199:Actins; D015638:Cytochalasin D