Auxins - plant growth substances, Biology

Assignment Help:

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.


Related Discussions:- Auxins - plant growth substances

How can you get a replacement, The book that I rented is missing some pages...

The book that I rented is missing some pages. How can i get a replacement?

What is glucose intolerance and diabetes, What is Glucose Intolerance and D...

What is Glucose Intolerance and Diabetes ? Insulin resistance, by perinsulinaemia and glucose intolerance appear to promote atherosclerosis. The prevalence of CAD raises from 2

Explain the blood plasma levels of calcium, Which of the following serves a...

Which of the following serves as a controlled variable in a negative feedback system? A. Levels of hydrogen ions in the interstitial spaces of the brainstem. B. Blood plasma

Requirements of glutamine in diverticular disease, Q. Requirements of Gluta...

Q. Requirements of Glutamine in diverticular disease? Glutamine: Wile specific nutrients that may have an impact on diverticula disease have not been studied as thoroughly as t

What are genotypes and phenotypes, The agouti locus in mice has three allel...

The agouti locus in mice has three alleles: A is recessive and confers a black coat, A is dominant to a and confers an agouti coat, and AY is dominant to both and confers a yellow

Microtubule assembly, Microtubule assembly: A) generally originates in the ...

Microtubule assembly: A) generally originates in the centrosome. B) occurs only during mitosis. C) occurs randomly throughout the cell. D) is regulated by myosin. E) is inhibited d

Define about calcium and osteoporosis, Define about Calcium and Osteoporosi...

Define about Calcium and Osteoporosis? Gain in bone mass occurs throughout childhood; however, during adolescent growth spurt, the gain in bone mass, as well as, calcium retent

What are the physical properties of tear film, What are the physical proper...

What are the physical properties of Tear Film? Physical Properties of Tear Film: The tear film is a three-layered structure as given below: 1) Outermost Layer: Lipid Layer

Explain dietary fibre - thyphoid, Dietary fibre Dietary fibre: Typhoid ...

Dietary fibre Dietary fibre: Typhoid patient has an inflamed intestinal mucosa, which can be easily perforated  and  ulcerated leading  to internal  haemorrhage. Thus foods hig

Explain the factors that lead to vitamin k deficiency, Explain the factors ...

Explain the factors that lead to vitamin K deficiency? The factors that lead to vitamin K deficiency include: 1) Marginal dietary intake if one undergoes trauma and extensiv

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd