Arabidopsis Biological Resource Center

Ploidy: 2

Phenotype: Plants exhibit developmental defects in leaves, flowers and siliques. Seeds harvested from heterozygous plants produce seedlings with a range of rosette phenotypes, including: a) normal rosettes, b) relatively small rosettes with serrated leaves (32% smaller than wild-type seedlings, are able to produce viable seeds, are dominant and heterozygous), and c) extremely small rosettes with narrow leaves and lethal (cease to grow in the juvenile stage and die); the serrated- and narrow-leaf mutant phenotypes are associated with the transgene insert, whereas the normal plants lacks a transgene. Plants display yellowish cauline leaves and sepals. Flowers have contorted and elongated petals and produce twisted siliques. The silique wall is wavy, such that the shape of individual seeds is apparent from the outside of the silique. During sensu stricto germination and post-germination, seeds and plants are hypersensitive to ABA in a dose-dependent manner. Mutants exhibit impaired seedling establishment (bent cotyledons, three cotyledons and three true leaves emerging at one time); although cotyledon development is altered in the mutant seedlings, the percentage seedling establishment on agar medium did not differ between wild-type and mARF10 plants during the early stages of development. The developmental defects in seedlings are more drastic when they are directly grown on soil, the smaller seedlings that eventually exhibit serrated leaves grow slowly, while most of the extremely small seedlings do not survive. Slower growth of the young mARF10 seedlings explains the reduction in size observed in plants at later stages in development.