Auxins - plant growth substances, Biology

Auxins - Plant Growth Substances

Julius Sachs (1882) first suggested on the basis of his observations that there are special substances for forming roots and some special substances for forming leaves etc. in plants (quite a far sighted hypothesis on the basis of strength of his scientific foresight). A decade earlier, Charles Darwin (known to all of us for his famous 'Theory of Evolution") and his son Francis studied the effect of gravity and unilateral light on the movement of plants. They demonstrated that the effects of light and gravity on the bending of both roots and shoots are mediated by the tip and that this influence can be transmitted to other parts of the plant.

Darwin was primarily interested in the coleoptile, which is a specialized leaf in the form of a hollow cylinder that enlcoses the epicotyl and is attached to the first node. It affords protection to the delicate growing tip of a grass seedling until, eventually the more rapidly first leaf emerges above ground. Paal and Hans Soding first approached this problem through experimental methods. They decapitated the coleoptile (removed the tip) and observed that this resulted in failure of coleoptiles to respond to light.

Posted Date: 1/24/2013 1:59:22 AM | Location : United States







Related Discussions:- Auxins - plant growth substances, Assignment Help, Ask Question on Auxins - plant growth substances, Get Answer, Expert's Help, Auxins - plant growth substances Discussions

Write discussion on Auxins - plant growth substances
Your posts are moderated
Related Questions
What is the significance of proteins for living beings? Proteins play a fundamental role in nearly all biological processes. Because of their diversity they can assume many dif

pioneers of developmental biology and their contribution

Define Pipette - Nutritional Biochemistry? Pipettes are used to deliver a known volume of liquid from one container to another. They are precision instruments of measurement an

Phases of Water The state of water can be changed from gaseous to liquid and liquid to solid and vice versa by the addition or removal of heat energy. To convert one gram of li

Illustrate the aqueous phase in sol processing In a sol possessing a continuous aqueous phase, the colloidal particles have an electrically charged surface.  The ionized groups

Define Citrate Utilization Test - imvic test? Several microorganisms have the ability to make use of citrate as the sole source of carbon and energy. This ability relies on the

Factors affects oxygen dissociation curve - Carbon dioxide Carbon dioxide lowers the oxygen affinity of haemoglobin even if the pH is kept constant. This effect is due to the

What are the Results of Chronic Pulmonary Thromboembolism? Results :  The reported mortality is between 5 and 24 per cent. On follow-up, the six-year survival in the best ce

Describe DNA replication in details? Replication :  DNA replicates itself by first breaking the hydrogen bonds between the nitrogen base pairs, and "unzips" itself into two s

Calculate Micronutrient and other specific nutrient requirements? The recommended average daily per capita intake of various specific nutrients for typical population requiring