Abstract
In wheat plants at the vegetative growth stage, the shoot apical meristem (SAM) produces leaf primordia. When reproductive growth is initiated, the SAM forms an inflorescence meristem (IM) that differentiates a series of spikelet meristem (SM) as the branch. The SM then produces a series of floret meristem (FM) as the branch. To identify the mechanisms that regulate formation of the reproductive meristems in wheat, we have investigated a leaf initiation mutant, fushi-darake (fdk) which was developed by ion beam mutagenesis. The morphological traits were compared in wild type (WT) and fdk mutant plants grown in the experimental field. WT plants initiated leaves from SAM at regular intervals in spiral phyllotaxy, while fdk plants had 1/2 alternate phyllotaxy with rapid leaf emergence. The fdk plants have increased numbers of nodes and leaves compared with WT plants. The time interval between successive leaf initiation events (plastochron) was measured in plants grown in a growth chamber. The fdk plants clearly show the rapid leaf emergence, indicating a shortened plastochron. Each tiller in fdk plants branches at the upper part of the culm. The fine structure of organ formation in meristems of fdk plants was examined by scanning electron microscopy (SEM). The SEM analysis indicated that fdk plants show transformation of spikelet meristems into vegetative shoot meristems. In conclusion, the fdk mutant has a heterochronic nature, i.e., both reproductive and vegetative programs were simultaneously in operation during the reproductive phase, resulting in a shortened plastochron and transformation of reproductive spikelets into vegetative shoots.
Highlights
Grasses such as wheat (Triticum aestivum) are the major source of carbohydrates for humans, and the yield of grain from these crops is largely dependent on inflorescence architecture
The fushi-darake mutant plant has been identified during the development of a large-scale mutant panel developed using heavy-ion beam mutagenesis [17]
The fdk showed drastic changes to their structural organization compared to wild type (WT) plants in the field (Figure 2A)
Summary
Grasses such as wheat (Triticum aestivum) are the major source of carbohydrates for humans, and the yield of grain from these crops is largely dependent on inflorescence architecture. A detailed understanding of development in wheat plants is of value to wheat breeding and for basic scientific research. In its vegetative growth phase, a wheat plant is composed of roots, stems, and leaves. Leaf initiation occurs at the base of the shoot apical meristem (SAM), a dome of cells, located at the tip of the shoot. One to three leaf primordia are initiated during embryogenesis. The SAM produces five to seven leaf primordia; the ac-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
