When etiolated radish (Raphanus sativus var. hortensis f. gigantissimus Makino) hypocotyls were subjected to a continuous unilateral illumination with white fluorescent light (0.1 watt per square meter), the growth rate at the lighted side was strongly inhibited for the first 2 hours, while that at the shaded side showed no change. After 2.5 hours growth on the lighted side recovered gradually,...

Ferrochelatase catalyzes the insertion of Fe2+ into protoporphyrin IX to generate protoheme. A putative mature region of a cucumber ferrochelatase cDNA (hemH) was overexpressed in Escherichia coli and purified to homogeneity (40 kDa). The optimum pH was 7.7, and the apparent K(m) values for deuteroporphyrin IX and Fe2+ were 14.4 microM and 4.7 microM, respectively. The activity of the ferrochel...

The DREB (dehydration-responsive element binding)-type transcription factors are classified into six subgroups, named A-1 to A-6. The members of DREB A-1 and A-2 subgroups have been reported to be involved in response to various abiotic stresses. However, there were only a few genes belonging to A-3 to A-6 subgroups to be reported. In this study, we cloned a DREB A-4 subgroup gene from maize (Z...

Microgreens growing under electric (artificial) lighting in controlled environments often have short hypocotyls, which can be difficult for machine harvest. To investigate whether early-stage dark treatment promote hypocotyl elongation without compromising microgreen yield and quality, two different seed-size species, sunflower (Helianthus annuus ‘Black oil’) arugula (Eruca sativa ‘Rocket’), we...

It has been proposed that spacing between cellulose microfibrils within plant cell walls may be an important determinant of their mechanical properties. A consequence of this hypothesis is that the water content of cell walls may alter their extensibility and that low water potentials may directly reduce growth rates by reducing cell wall spacing. This paper describes a number of experiments in...

The effect of auxin application on auxin metabolism was investigated in excised hypocotyl cultures of carrot (Daucus carota). Concentrations of both free and conjugated indole-3-acetic acid (IAA), [2H4]IAA, 2,4-dichlorophenoxyacetic acid, and naphthaleneacetic acid (NAA) were measured by mass spectroscopy using stable-isotope-labeled internal standards. [13C1]NAA was synthesized for this purpos...

Gravitropic asymmetry of auxin was observed in hypocotyls of tomato (Lycopersicon esculentum Mill.) soon after horizontal placement: the ratio of apically supplied [3H]IAA collected from the lower sides to that from the upper sides was about 1.4 between 5 and 10 minutes. This was adequately early to account for the beginning of curvature. The auxin asymmetry ratio rose to about 2.5 between 2...

Cellulase activity was measured in soybean (Glycine max) leaf abscission zones, flower abscission zones, pod abscission zones, apical buds, and adventitious rooting hypocotyls. Immunoprecipitation data showed that a cellulase immunologically similar to the bean abscission cellulase (isoelectric point 9.5) is present in soybean leaf, flower, and pod abscission zones, but is not present in soybea...

Hypocotyls from etiolated cucumber (Cucumis sativa L.) seedlings were gently abraded at their surface to allow permeation of elicitors. Segments from freshly abraded hypocotyls were only barely competent for H(2)O(2) elicitation with fungal elicitor or hydroxy fatty acids (classical cutin monomers). However, elicitation competence developed subsequent to abrasion, reaching an optimum after abou...