Биохимические мутан ты высших растений ка к объекты для химических и физиологических исс ледований. — Обзор

Abstract

A report is given on biochemical mutants in higher plants with emphasis on metabolic mutants. Since the discovery of thiamine-defective mutants inArabidopsis thaliana andLycopersicon esculentum some other mutants in different species became available. The first higher plant with an absolute requirement for an amino acid is a proline-deficient mutant inZea mays. Inchloronerva ofLycopersicon esculentum synthesis of nicotianamine is blocked. This is the first instance where a hitherto unknown function is attributed to an already known compound by work with a mutant of higher plants. Nicotianamine is distributed throughout all vascular plants and appears to be linked with short-distance iron transport. The wilty mutantflacca inL. esculentum lacks abscisic acid with some consequences to different parts of metabolism. In the same species the mutant T 3238btl/btl, fer/fer carries two separate, independent mutations which affect the transport of boron and iron, respectively. Selection for chlorate resistance led to the discovery of mutants with impaired nitrate reductase activity and nitrate uptake inArabidopsis thaliana and in consequence added new information to our knowledge of the regulation of nitrate assimilation. Other mutants of similar kind were detected inNicotiana tabacum andHordeum vulgare. Mutants with defects in the photosynthetic system were discovered inZea mays andHordeum vulgare. Plastome mutants inOenothera revealed a lack of ribulose-1,5-biphosphate carboxylase activity and showed interference between the genetic system of the plastids and that of the nucleus.