Contrasting modes of regulation of PS II light utilization with changing irradiance in normal and psbS mutant leaves of Arabidopsis thaliana.

Complementary techniques of chlorophyll a fluorescence, steady state CO(2) exchange, and O(2) release during a multiple turnover flash were applied to compare responses to irradiance for leaves of wild type and psbS mutants. The latter included variants in which the psbS gene was deleted (npq4-1) or possessed a single point mutation (npq4-9). Nonphotochemical quenching (NPQ) was reduced by up to 80 and 50%, respectively, in these lines at high irradiance.

The multiphasic nature of nonphotochemical quenching: implications for assessment of photosynthetic electron transport based on chlorophyll fluorescence.

Defining a quantitative relationship between chlorophyll a fluorescence yield and Photosystem II (PS II) function is important to photosynthesis research. Prior work [Peterson and Havir (2003) Photosynth Res 75: 57-70] indicated an apparent effect of psbS genotype on the in vivo rate constant for photochemistry in PS II (k(P0)). The nuclear psbS gene encodes a 22-kDa pigment-binding antenna protein (PS II-S) essential for photoprotective nonphotochemical quenching (NPQ) in PS II.

Photosynthetic properties of an Arabidopsis thaliana mutant possessing a defective PsbS gene.

We describe the properties of npq4-9, a new mutant of Arabidopsis thaliana (L.) Heynh. with reduced nonphotochemical quenching (NPQ) capacity that possesses a single amino acid substitution in the PsbS gene encoding PSII-S, a ubiquitous pigment-binding protein associated with photosystem II (PSII) of higher plants.

A nonphotochemical-quenching-deficient mutant of Arabidopsis thaliana possessing normal pigment composition and xanthophyll-cycle activity.

Higher-plant chloroplasts alter the distribution of absorbed radiant energy between photosynthesis and heat formation in response to changing illumination level or environmental stress. Fluorescence imaging was used to screen 62 yellow-green T-DNA insertion mutant lines of Arabidopsis thaliana (L.) Heynh.

Manipulation of catalase levels produces altered photosynthesis in transgenic tobacco plants.

Constructs containing the cDNAs encoding the primary leaf catalase in Nicotiana or subunit 1 of cottonseed (Gossypium hirsutum) catalase were introduced in the sense and antisense orientation into the Nicotiana tabacum genome. The N. tabacum leaf cDNA specifically overexpressed CAT-1, the high catalatic [corrected] form, activity.