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Seedling growth is also affected by mechanical stimulation, such as by wind or other forms of physical contact, through a process called thigmomorphogenesis. Temperature and light intensity interact as they affect seedling growth; at low light levels about 40 lumens/m 2 a day/night temperature regime of 28 °C/13 °C is effective (Brix 1972). [ 2 ]
It is a measure of germination time course and is usually expressed as a percentage, e.g., an 85% germination rate indicates that about 85 out of 100 seeds will probably germinate under proper conditions over the germination period given. Seed germination rate is determined by the seed genetic composition, morphological features and ...
Pinus albicaulis is the only type of tree on the summit of Pywiack Dome in Yosemite National Park. Pinus albicaulis, known by the common names whitebark pine, white bark pine, white pine, pitch pine, scrub pine, and creeping pine, [4] is a conifer tree native to the mountains of the western United States and Canada, specifically subalpine areas of the Sierra Nevada, Cascade Range, Pacific ...
Seed germination is a process by which a seed embryo develops into a seedling. It involves the reactivation of the metabolic pathways that lead to growth and the emergence of the radicle or seed root and plumule or shoot. The emergence of the seedling above the soil surface is the next phase of the plant's growth and is called seedling ...
Viable seeds produced by a mature tree undergo Stratification. [2] This process imitates the period of dormancy that occurs during the winter. [2] In the commercial Christmas Tree nurseries of the northern United States, seeds are sown directly into seed beds in the late fall to allow the seeds to stratify naturally over the winter.
Eastern white pine is self-fertile, but seeds produced this way tend to result in weak, stunted, and malformed seedlings. Mature trees are often 200–250 years old, and some live over 400 years. A tree growing near Syracuse, New York , was dated to 458 years old in the late 1980s and trees in Michigan and Wisconsin were dated to roughly 500 ...
In the Chippewa National Forest (Lake States), seed-spot sowing of 10 seeds each of white spruce and white pine under 40-year aspen after different degrees of cutting on gave second-season results clearly indicating the need to remove or disturb the forest floor to obtain germination of seeded white spruce and white pine. [133]
Longleaf pine (Pinus palustris) is a pyrophile, depending on fire to clear the ground for seed germination. [4] The passage of fire, by increasing temperature and releasing smoke, is necessary to raise seeds dormancy of pyrophile plants such as Cistus and Byblis an Australian passive carnivorous plant. Imperata cylindrica is a plant of Papua ...