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Time course imaging of two maize inbreds and their F1 hybrid (middle) exhibiting heterosis.. Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring.
The word hybridity was in use in English since the early 17th century and gained popular currency in the 19th century. Charles Darwin used the term in 1837 in reference to his experiments in cross-fertilization in plants. The concept of hybridity has been fraught with negative connotations from its incipience.
Growth due to gravitropism is mediated by changes in concentration of the plant hormone auxin within plant cells. In the process of plant shoots growing opposite the direction of gravity by gravitropism, high concentration of auxin moves towards the bottom side of the shoot to initiate cell growth of the bottom cells, while suppressing cell ...
In physics, gravity (from Latin gravitas ' weight ' [1]) is a fundamental interaction primarily observed as a mutual attraction between all things that have mass.Gravity is, by far, the weakest of the four fundamental interactions, approximately 10 38 times weaker than the strong interaction, 10 36 times weaker than the electromagnetic force, and 10 29 times weaker than the weak interaction.
The rate at which the velocity of a body changes with time, also the rate of change of the rate at which the position of a body changes with time. acceleration due to gravity The acceleration on an object caused by the force of gravitation. accelerometer An instrument used to measure the proper acceleration of a body irrespective of other ...
In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter: solid, liquid, and gas, and in rare cases, plasma.
A contour plot of the effective potential due to gravity and the centrifugal force of a two-body system in a rotating frame of reference. (In the context of this article the two bodies are the Sun—the yellow body—and Earth—the dark body between L1 and L2. The Counter-Earth would exist at L3.)
The actual rate at which atmospheric temperature changes with altitude, as measured by a radiosonde; this is in contrast to the rate predicted by the theoretical process lapse rate. On average, the temperature of the troposphere decreases with height at a rate of 6.5 °C (11.7 °F) per kilometre, but this rate is influenced by many factors.