if dermal tissue covers the entire plant,then what about the gaseous exchange for inner tissues of plants
Answers
AS FOR ALL ANIMALS, YOUR BODY IS MADE OF FOUR TYPES OF TISSUE: EPIDERMAL, MUSCLE, NERVE, AND CONNECTIVE TISSUES. PLANTS, TOO, ARE BUILT OF TISSUES, BUT NOT SURPRISINGLY, THEIR VERY DIFFERENT LIFESTYLES DERIVE FROM DIFFERENT KINDS OF TISSUES. ALL THREE TYPES OF PLANT CELLS ARE FOUND IN MOST PLANT TISSUES. THREE MAJOR TYPES OF PLANT TISSUES ARE DERMAL, GROUND, AND VASCULAR TISSUES.
DERMAL TISSUE
DERMAL TISSUE COVERS THE OUTSIDE OF A PLANT IN A SINGLE LAYER OF CELLS CALLED THE EPIDERMIS . YOU CAN THINK OF THE EPIDERMIS AS THE PLANT’S SKIN. IT MEDIATES MOST OF THE INTERACTIONS BETWEEN A PLANT AND ITS ENVIRONMENT. EPIDERMAL CELLS SECRETE A WAXY SUBSTANCE CALLED CUTICLE , WHICH COATS, WATERPROOFS, AND PROTECTS THE ABOVE-GROUND PARTS OF PLANTS. CUTICLE HELPS PREVENT WATER LOSS, ABRASIONS, INFECTIONS, AND DAMAGE FROM TOXINS.
THIS TISSUE INCLUDES SEVERAL TYPES OF SPECIALIZED CELLS. PAVEMENT CELLS, LARGE, IRREGULARLY SHAPED PARENCHYMAL CELLS WHICH LACK CHLOROPLASTS, MAKE UP THE MAJORITY OF THE EPIDERMIS. WITHIN THE EPIDERMIS, THOUSANDS OF PAIRS OF BEAN-SHAPED SCHLERENCHYMAL GUARD CELLS SWELL AND SHRINK BY OSMOSIS TO OPEN AND CLOSE STOMATA, TINY PORES WHICH CONTROL THE EXCHANGE OF OXYGEN AND CARBON DIOXIDE GASES AND THE RELEASE OF WATER VAPOR. THE LOWER SURFACES OF SOME LEAVES CONTAIN AS MANY AS 100,000 STOMATA PER SQUARE CENTIMETER.