BIO120H1 Lecture Notes - Lecture 17: Sclerophyll, Evaporative Cooler, Mnemonic
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BIO120H1 Full Course Notes
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Lecture 17: physiological ecology of plants: more tradeoffs. High sa:v ratio is essential for photosynthesis however lose lots of water. Microphylly: reduced size of leaves in order to conserve water/stay cool. Keeping cool while conserving water: sonoran desert, arizona: palo verde (green stick): Photosynthetic trunk and branches can grow without incurring heat load and water loss through leaves. Small leaves (microphylly: mesquite: slightly bigger leaves than palo verde, santa rita prickly pear: no leaves (extreme microphylly, cacti: extensive but shallow roots, episodic water patterns, saguaro cactus: adapted to episodic rains. Grows to 15 m, 200 yr, 5+ tonnes. Can absorb 800 l of water from one storm, use it gradually for growth. Mnemonic digression for water storage: david grundman (d. 1982) Animals can evade stress through behaviour: what about plants: deciduous habit: dropping leaves during dry or cold seasons can reduce water stress and tissue damage, (cid:862)evergree(cid:374)(cid:863): loose sy(cid:374)o(cid:374)y(cid:373) for (cid:862)co(cid:374)ifer(cid:863)
