Table I.
Characteristics of root hairs and reductase activity in wild-type and mutant plants
| Gene | Mutant Phenotype | Root Ferric Reductase Activity +Fe/−Fe | Reference |
|---|---|---|---|
| Ecotypes | |||
| Col-0 | Columbia | −/++ | |
| Ler-0 | Landsberg erecta | −/++ | |
| La-0 | Landsberg | −/++ | |
| Ws-0 | Wassilewskija | −/++ | |
| Hormone-related mutants | |||
| aba1-1 (Ler) | Abscisic acid deficient | −/++ | Koorneef et al. (1982) |
| aba1-3 (Ler) | Abscisic acid deficient | −/++ | Koorneef et al. (1982) |
| aba1-4 (Ler) | Abscisic acid deficient | −/++ | Koorneef et al. (1982) |
| abi1-1 (Ler) | Abscisic acid insensitive | −/++ | Koorneef et al. (1984) |
| abi2-1 (Ler) | Abscisic acid insensitive | −/++ | Koorneef et al. (1984) |
| abi3-1 (Ler) | Abscisic acid insensitive | −/++ | Koorneef et al. (1984) |
| abi4 | Abscisic acid insensitive | −/++ | Finkelstein (1994) |
| abi5-1 (Ws) | Abscisic acid insensitive, fewer root hairs | −/++ | Finkelstein (1994) |
| amp1 | Altered meristem program, enhanced level of cyt | −/++ | Chaudhury et al. (1993) |
| aux1-7 | Auxin insensitive, display resistance to various hormones, reduced number of root hairs | −/+ | Pickett et al. (1990) |
| axr1-3 | Auxin resistant, display resistance to various hormones, decreased formation of root hairs | −/++ | Estelle and Sommerville (1987), Lincoln et al. (1990) |
| axr1-12 | Auxin resistant, display resistance to various hormones, very few root hairs | −/+ | Estelle and Sommerville (1987), Lincoln et al. (1990) |
| axr2 | Auxin resistant, display resistance to various hormones, nearly root hairless, cells with multiple root hairs | −/+ | Wilson et al. (1990), Lincoln et al. (1990), Evans et al. (1994) |
| axr4-1 | Auxin resistant, reduced number of root hairs | −/+(+) | Hobbie and Estelle (1995) |
| axr4-2 | Auxin resistant, reduced number of root hairs | −/+(+) | Hobbie and Estelle (1995) |
| aux1-7/axr4-2 | Double mutant, reduced number of root hairs | −/+(+) | Hobbie and Estelle (1995) |
| axr1-3/axr4-2 | Double mutant, reduced number of root hairs | −/+(+) | Hobbie and Estelle (1995) |
| cin1 | Cytokinin insensitive | −/+(+) | Vogel et al. (1998) |
| cin2 | Cytokinin insensitive | −/+(+) | Vogel et al. (1998) |
| ctr1-1 | Constitutive triple response, excessive root hairs, ectopic root hairs | −/++(+) | Kieber et al. (1993) |
| cri1-1 | Cristal-phenotype, cytokinin overaccumulator | −/+ | Santoni et al. (1997) |
| cyr1 | Cytokinin resistant | −/(+) | Deikman and Ulrich (1995) |
| ein2-1 | Ethylene insensitive | −/++ | Guzmán and Ecker (1990), Kieber et al. (1993) |
| ein3-1 | Ethylene insensitive | −/++ | Kieber et al. (1993), Roman et al. (1995) |
| ein4 | Ethylene insensitive | −/++ | Roman et al. (1995) |
| ein5-1 | Ethylene insensitive | −/++ | Roman et al. (1995) |
| ein6 (Ler) | Ethylene insensitive | −/++ | Roman et al. (1995) |
| ein7 | Ethylene insensitive | −/++ | Roman et al. (1995) |
| eir1-1 | Ethylene insensitive root, shoot is sensitive | −/+(+) | Roman et al. (1995) |
| ers1-1 | Ethylene response sensor, ethylene insensitive | −/++ | Hua et al. (1995) |
| eti5 | Ethylene insensitive | −/+(+) | Harpham et al. (1991) |
| eto1 | Ethylene overproducer, increased number of root hairs | −/++(+) | Guzmán and Ecker (1990) |
| eto2 | Ethylene overproducer, increased number of root hairs | −/+++ | Kieber et al. (1993) |
| eto3 | Ethylene overproducer, very much root hairs | −/+++(+) | Kieber et al. (1993) |
| etr1-1 | Ethylene resistant | −/++ | Bleecker et al. (1988), Chang et al. (1993) |
| etr1-3 | Ethylene resistant | −/++ | Bleecker et al. (1988) |
| fs1 (Ler) | Fass, auxin level enhanced | −/+ | Torres-Ruiz and Jürgens (1994)stp1 |
| stp1 | Stunted plant, low cyt response | −/+(+) | Baskin et al. (1995) |
| sur1 | Superroot, auxin overproducer | −/++ | Boerjan et al. (1995) |
| tir3-1 | (Auxin) transport inhibitor response, defect in polar auxin transport | −/++ | Ruegger et al. (1997) |
| Gene | Mutant Phenotype | Root Ferric Reductase Activity +Fe/−Fe | Reference |
|---|---|---|---|
| Root hair mutants | |||
| cpc | Caprice, few irregular root hairs | −/++ | Wada et al. (1997) |
| gl2-1 | Glabra, root hairs on almost every root epidermal cell | −/++(+) | Masucci et al. (1996) |
| rgr1 (Ws) | Reduced root gravitropism, resistant towards inhibitors of polar auxin trans | −/++ | Simmons et al. (1995) |
| gl1-1/rhd2-1 | Double mutant | −/++ | Schiefelbein and Somerville (1990) |
| ttg1 (Ler) | Transparent testa glabra, root hairs on almost every root epidermal cell | −/++(+) | Galway et al. (1994) |
The intensity of the staining by +Fe and −Fe plants is indicated by + and − symbols. Fe-sufficient wild-type roots, showing virtually no activity during the experimental period, was defined as −, the intensity of the reaction of −Fe wild-type and mutant roots was indicated by using the following scale in the order of increasing activity: + < ++ < +++ < ++++. Values in parentheses indicate intermediate levels of intensity.