Willmann, Matthew R. Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania.
- Juvenile and adult vegetative phases
- Relationship between vegetative phase change and reproductive onset
- Small RNAs regulate the juvenile-to-adult transition
- Related Primary Literature
- Additional Reading
The reproductively incompetent juvenile vegetative phase of seed plants, often with morphological and physiological characteristics that differ from those of an adult plant. The development of the aboveground portion of seed plants, also called the shoot, is characterized by four phases: embryonic, juvenile vegetative, adult vegetative, and reproductive. The embryonic stage includes the period between the fertilization of an egg and the formation of a mature embryo within a seed. In contrast to animal embryos, plant embryos do not contain precursors of all of the organs found in an adult plant. Instead, the embryonic phase establishes the basic axes of growth, and new organs are continually formed throughout the life of the plant from a pool of stem cells at each end of the shoot–root axis. These stores of stem cells are called the shoot apical meristem (SAM) and the root apical meristem (RAM), respectively. Thus, whereas the apical end of an angiosperm embryo includes only one or two cotyledons, one or more immature true leaves, and the SAM, the plant upon germination repeatedly initiates new organs from the SAM—first vegetative organs (leaves, stems, and branches) and then reproductive ones (flowers). See also: Apical meristem; Plant; Plant development; Plant growth; Plant organs; Plant physiology; Seed; Stem cells
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information