Mechanism Of Stomatal Movement

-

 

MECHANISM OF STOMATAL MOVEMENTS

 

1) STARCH- SUGAR HYPOTHESIS:

It is proposed by sayer in 1923

IN LIGHT:

IN DARK:

Photosynthesis occurs

Respiration occurs

pH increases↑

pH decreases ↓

Carbon dioxide Co₂↓

Carbon dioxide Co₂ ↑

Enzyme: phosphorylase is used

Enzyme: phosphorylase is used

Sugar increases ↑ so endosmosis take place

Starch increases ↑ so exosmosis take place

Turgor pressure increases ↑

Turgor pressure decreases ↓

Diffusion pressure deficit (DPD) increases ↑

Diffusion pressure deficit (DPD) decreases ↓

Stomata = opens

Stomata = closes

Starch is converted in to glucose -1- phosphate

glucose -1- phosphate is converted in to Starch

 

 

 


2) STEWARD HYPOTHESIS:

It is proposed by steward in 1964

IN LIGHT:

IN DARK:

Photosynthesis occurs

Respiration occurs

pH increases↑

pH decreases ↓

Carbon dioxide Co₂↓

Carbon dioxide Co₂ ↑

Enzyme: phosphorylase is used

Enzyme: Heterokinase is used

Turgor pressure increases ↑

Turgor pressure decreases ↓

Diffusion pressure deficit (DPD) increases ↑

Diffusion pressure deficit (DPD) decreases ↓

Stomata = opens

Stomata = closes

Starch is converted in to glucose + phosphate

glucose - 6 - phosphate is converted in to Starch

 

 

 


3) THEORY OF K^ + TRANSPORT:

It is proposed by Levit in 1974

IN LIGHT:

IN DARK:

K^+ started entering into guard cell

K^+ stops entering into guard cell

pH increases↑

pH decreases ↓

Guard cell becomes turgid

Guard cell becomes flaccid

Turgor pressure increases ↑

Turgor pressure decreases ↓

Diffusion pressure deficit (DPD) increases ↑

Diffusion pressure deficit (DPD) decreases ↓

  1. Increases in accessory cells↑
  2. Decreases in guard cells↓

Stomata = opens

Stomata = closes

Starch is converted in to potassium malate

potassium malate is converted in to malic acid


Comments

Post a Comment

Popular posts from this blog

Krebs cycle or Citric acid cycle or TCA cycle

-
Image
 Krebs cycle or Citric acid cycle or TCA cycle   Two molecules of acetyl CoA formed from link reaction now enter into Krebs cycle. It is named after its discoverer, German Biochemist Sir Hans Adolf Krebs (1937). The enzymes necessary for TCA cycle are found in mitochondrial matrix except succinate dehydrogenase enzyme which is found in mitochondrial inner membrane. TCA cycle starts with condensation of acetyl CoA with oxaloacetate in the presence of water to yield citrate or citric acid. Therefore, it is also known as Citric Acid Cycle (CAC) or Tri Carboxylic Acid (TCA) cycle. It is followed by the action of different enzymes in cyclic manner. During the conversion of succinyl CoA to succinate by the enzyme succinyl CoA synthetase or succinate thiokinase, a molecule of ATP synthesis from substrate without entering the electron transport chain is called substrate level phosphorylation. In animals a molecule of GTP is synthesized from GDP+Pi. In a coupled reaction GTP is conve...
Read more

GARDEN IMPLEMENTS

-
Image
                                                                 GARDEN IMPLEMENTS   Pick axe: pickle axe is a ‘T’ shaped hand tool used for prying. Its head is typically metal, attached perpendicular to a longer handle. It is used for breaking up rocks or ground, in construction and mining, prying the axe of hoeing, skimming and chopping through roots.   Axe: axe is an implement that has been used for shape, split and cut wood. It has two primary components: the head and the haft. It is used for chopping, splitting, chipping, piercing, to harvest timber, weapon, ceremonial or heraldic symbol. Shovel: shovel is a hand tool consist of a broad blade fixed to a ...
Read more

Heterosis- discovery, definition, types & mutation, polyploid breeding

-
Image
                                                                                     Heterosis Discovery: Heterosis (hetero- different; sis - condition) G.H. Shull was the first scientist to use the term heterosis in 1912.  Definition: The superiority of the F1 hybrid in performance over its parents is called heterosis or hybrid vigour. Vigour refers to increase in growth, yield, greater adaptability of resistance to diseases, pest and drought. Vegetative propagation is the best suited measure for maintaining hybrid vigour, since the desired characters are not lost and can persist over a period of time. Many breeders believe that the magnitude of heterosis is directly related to the degree of genetic diversity between the two par...
Read more