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External Factors and Plant Growth - Botany - Lecture Slides, Slides of Botany and Agronomy

These are the important key points of lecture slides of Botany are:External Factors and Plant Growth, Nastic Movement, External Factors, Plant Growth, Direction of Growth, Phototropic Response, Bur Cucumber, Common Response, Diurnal Movements, Wood Sorrel

Typology: Slides

2012/2013

Uploaded on 01/09/2013

prakash
prakash 🇮🇳

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External factors and Plant growth
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External factors and Plant growth

Nastic Movement

  • Nastic Movements- plants movement that occur in response to a stimulus independent of position of stimulus ( leaves light and dark cycle)
  • Phototropism- response to light- caused by elongation- under the influence of Auxin
  • Gravitropism- response to gravity
  • Thigmotropism- response to touch

Went’s experiment- chemical produced by growing tips influences direction of growth

What role does the light play in the

phototropic response?

  • Light decreases the auxin sensitivity of the cells on the lighted side
  • Light destroys auxin
  • Light drives auxin to the shaded side

‘Light eliminates auxin activity’

Tropism video

Auxin and root gravitropism

Gravitism video Docsity.com

Thigmotorpism- tendrils of bur cucumber, twisting Caused by different growth Rates on the inside and Outside of tendril

Phototropism

  • Common response to light

Diurnal movement- biological clock is the organism

keeping itself in time with some external stimulus?

Other types of Movement

  • Thigmonastic (seismonastic) Movement are results of mechanical stimulation
  • Most night closure (nyctinastic movement) are results from changes in the size of perenchyma cells in the jointlike thickening (pulvinus) structure at the base of each leaf.

Mimosa pudica