Flowering of Arabidopsis is promoted by long days and delayed by short days. Mutations in the GIGANTEA (GI) gene delay flowering under long days but have little or no effect under short days. We have now isolated the GI gene and show that it encodes a novel, putative membrane protein. By comparing the sequence of the Arabidopsis gene with that of a likely rice orthologue and by sequencing mutan...

Photoperiod controls several responses throughout the plant life cycle, like germination, flowering, tuber formation, onset of bud dormancy, leaf abscission, and cambium activity. From these processes, flowering has been most extensively studied, especially in Arabidopsis thaliana. Photoperiod sensing by the function of photoreceptors and the circadian clock appears to regulate flowering time v...

Phytochromes are dimeric proteins that function as red and far-red light sensors influencing nearly every phase of the plant life cycle. Of the three major phytochrome families found in flowering plants, phytochrome C (PHYC) is the least understood. In Arabidopsis and rice, PHYC is unstable and functionally inactive unless it heterodimerizes with another phytochrome. However, when expressed in ...

To investigate the genetic basis of maize adaptation to temperate climate, collections of 375 inbred lines and 275 landraces, representative of American and European diversity, were evaluated for flowering time under short- and long-day conditions. The inbred line collection was genotyped for 55 genomewide simple sequence repeat (SSR) markers. Comparison of inbred line population structure with...

Ascorbic acid (AA) protects plants against abiotic stress. Previous studies suggested that this antioxidant is also involved in the control of flowering. To decipher how AA influences flowering time, we studied the four AA-deficient Arabidopsis (Arabidopsis thaliana) mutants vtc1-1, vtc2-1, vtc3-1, and vtc4-1 when grown under short and long days. These mutants flowered and senesced before the w...

Background & Aim: German chamomile is one of the most important medicinal plants. So, assessment of genetic diversity and relationship among the traits are very essential in chamomile breeding programs. Determination of the best indirect selection criteria for genetic improvement of essence percent and dry flower yield of German chamomile (Matricaria chamomilla L.) populations...

Arabidopsis flowers early under long days (LD) and late under short days (SD). The repressor of photomorphogenesis DE-ETIOLATED1 (DET1) delays flowering; det1-1 mutants flower early, especially under SD, but the molecular mechanism of DET1 regulation remains unknown. Here we examine the regulatory function of DET1 in repression of flowering. Under SD, the det1-1 mutation causes daytime expressi...

One of the most important environmental factors affecting flowering time is the daily duration of light, the photoperiod, which was first discovered by Garner and Allard in the 1920s (Thomas and Vince-Prue, 1997, and refs. therein). Plants in which flowering occurs or is accelerated in short days (SD) or long days (LD) are known as SD plants or LD plants, respectively. LD plants often flower in...

in order to determine of the proper sowing date of steckling (rootlet) and harvesting date of seed, an experiment was conducted in ardabil agricultural research station (alarough) in 2004- 05 growing season in split-plot in randomized complete block design arrangement with four replications. four different planting dates viz. 5th march, 20th march, 4th april and 19th april– were allocated to th...

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