Cork formation in table beet leaves (Beta vulgaris) in response to smog

Book · Sat Jan 01 04:00:00 EST 1955

OSTI ID:6410496

Bobrov, R A

Table beet (Beta vulgaris) leaves produce an abnormal corklike layer, the cicatrice, on their lower surface in response to smog. This is due to a series of cross walls which cut in parallel to the broad surface of the leaf in normally static, spongy mesophyll cells. Following exposure to smog, a limited number of cells surrounding the substomatal chambers on the lower leaf surface become dehydrated. Anthocyanin increases in the damaged areas and lower epidermal cells may collapse. The walls of the initially damaged cells, those of the collapsed epidermal cells, and intercellular spaces between become heavily suberized, sealing the lower surface of the leaf. Sudan III stains this region readily. This layer is properly designated the pseudocicatrice. All are functional, the only abnormality is in the region of accelerated suberization. The cells of the lower spongy mesophyll in the immediate vicinity of damage begin to divide by tangential walls to form a cicatrice parallel to the flat surface of the blade. These new walls are at first pure cellulose. As they grow older, they become more and more heavily suberized. By compression against one another as the mother cell continues to form new walls above, a heavily suberized protective cork layer, the cicatrice, is formed. This stimulation to unusual wall formation in cells, which under normal conditions would not enlarge or divide, is definitely in response to tissue trauma. Renewed cellular activity cannot be blamed directly on the toxicity of a smog component. Indirectly, however, by causing the death of some cells, it may induce chemical changes within the leaf, which, in turn, induce the formation of cork. 44 references, 6 figures.

• OSTI ID: 6410496
• Country of Publication: United States
• Language: English

Related Subjects

560303* -- Chemicals Metabolism & Toxicology-- Plants-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AIR POLLUTION
BEETS
BIOLOGICAL EFFECTS
BIOSYNTHESIS
CELL CONSTITUENTS
CELL WALL
CORK
FOOD
GROWTH
LEAVES
PLANT CELLS
PLANT GROWTH
PLANTS
POLLUTION
SENSITIVITY
SMOG
SYNTHESIS
TOXICITY
VEGETABLES