Скачать или смотреть Skotomorphogenesis And Photomorphogenesis | Plant Physiology

Skotomorphogenesis and photomorphogenesis are two distinct developmental processes in plants that are regulated by light conditions. They reflect how plants adapt their growth depending on whether they are in the dark or exposed to light.

Skotomorphogenesis (Growth in Darkness):

This is the developmental pattern plants undergo when they are grown in the absence of light.

Key features include:

Elongated hypocotyl (stem): The seedling elongates rapidly, searching for light.

Closed and yellowish cotyledons (seed leaves): Cotyledons remain closed to conserve energy.

Apical hook formation: The stem curves at the top, protecting the shoot meristem from damage as it pushes through the soil.

Etiolation: This overall growth pattern is aimed at helping the plant emerge from the soil and find light.



Photomorphogenesis (Growth in Light):

This refers to the developmental process that plants undergo in the presence of light.

Key features include:

Shortened hypocotyl: The stem stops elongating once exposed to light.

Opening and greening of cotyledons: Chlorophyll is produced, and the plant begins photosynthesis.

Leaf development and stem growth: The plant shifts resources towards producing leaves and photosynthetic organs rather than elongating to search for light.



Significance:

Skotomorphogenesis ensures the plant conserves energy while growing in darkness, focusing on reaching the surface as quickly as possible.

Photomorphogenesis allows the plant to optimize growth by absorbing light and transitioning into full photosynthetic activity once exposed to sunlight.


These processes are regulated by various light-sensitive proteins, such as phytochromes and cryptochromes, which detect light and trigger the respective developmental responses.

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