The role of abscisic acid (ABA) during early development was investigated in tomato seedlings. The endogenous content of ABA in particular organs was analyzed in seedlings grown in the dark and under blue light. Our results showed that in dark-grown seedlings, the ABA accumulation was maximal in the cotyledons and elongation zone of hypocotyl, whereas under blue-light, the ABA content was disti...

Introduction Trhe titration curve for the expressed juice of etiolated wheat seedlings has a pronounced inflection above pH 8.0 (fig. 4), which does not occur in the curve for fully green seedlings (fig. 5). An intermediate type of curve, linear between p1I 8.5 and 11.0, is characteristic of very young seedlings just after their emergence from the ground. when, from the standpoint of chemical c...

BACKGROUND PhyC levels have been observed to be markedly lower in phyB mutants than in Arabidopsis or rice wild type etiolated seedlings, but the mechanism of this phenomenon has not been fully elucidated. RESULTS In the present study, we investigated the mechanism by which phyB affects the protein concentration and photo-sensing abilities of phyC and demonstrated that rice phyC exists predom...

It has been reported that Arabidopsis phytochrome (phy) A and phyB are crucial photoreceptors that display synergistic and antagonistic action during seedling de-etiolation in multiple light signaling pathways. However, the functional relationship between phyA and phyB is not fully understood under different kinds of light and in response to different intensities of such light. In this work, we...

Numerous investigators have worked on the problem of determining the effect of small quantities of visible radiant energy on seedlings and other plants with stored foods. The literature is extensive and goes back over one hundred years. MAcDOUTGAL (6) has thoroughly reviewed the work before 1900 while TRUMPF (9) and BURKHOLDER (1) have reviewed this and much of the later work. The work before 1...

In etiolated seedlings, phytochrome A (phyA) mediates very-low-fluence responses (VLFRs), which initiate de-etiolation at the interphase between the soil and above-ground environments, and high-irradiance responses (HIR), which complete de-etiolation under dense canopies and require more sustained activation with far-red light. Light-activated phyA is transported to the nucleus by FAR-RED ELONG...

BACKGROUND Etiolated seedlings initiate grana stacking and chlorophyll biosynthesis in parallel with the first exposure to light, during which phytochromes play an important role. Functional phytochromes are biosynthesized separately for two components. One phytochrome is biosynthesized for apoprotein and the other is biosynthesized for the chromophore that includes heme oxygenase (HO). METHO...

Phytochrome A (phyA) is the primary photoreceptor mediating deetiolation under far-red (FR) light, whereas phyB predominantly regulates light responses in red light. SUPPRESSOR OF PHYA-105 (SPA1) forms an E3 ubiquitin ligase complex with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1), which is responsible for the degradation of various photomorphogenesis-promoting factors, resulting in desensitization t...