Chapter 35 Plant Growth AP Biology Indeterminate growth

Chapter 35. Plant Growth AP Biology

Indeterminate growth § Unlike animals most plants grow throughout their life u annuals § life cycle within 1 year § germination flowering seed production u perennials § live many years § does not die of old age, only disease or trauma AP Biology

Meristem § Regions of growth perpetually embryonic tissue u regenerate new cells u § apical shoot meristem w growth in length w primary growth § apical root meristem w growth in length w primary growth § lateral meristem w growth in girth w secondary growth AP Biology

Apical meristems AP Biology shoot root

Root structure & growth AP Biology

Shoot growth § Apical bud & primary growth of shoot region of stem growth u axillary buds “waiting in the wings” u AP Biology

Shoot growth § Since woody plants grow from year to year, they evolved a different growth system than herbaceous plants which die back each year AP Biology woody herbaceous

Growth in woody plants § Woody plants grow in height from tip u u primary growth apical meristem § Woody plants grow in diameter from sides u u secondary growth vascular cambium § vascular meristem layer AP Biology

Growth in woody plants § Primary growth tips of roots & shoots (apical meristem) u restricted to youngest parts of plant u shoot AP Biology root

Growth in woody plants § Secondary growth u thickens & strengthens older part of tree u cork cambium makes bark § growing ring around tree u vascular cambium makes xylem & phloem § growing ring around tree AP Biology

Woody stem § Phloem produced to the outside § Xylem produced to the inside cork cambium bark phloem late vascular cambium AP Biology xylem early

cork cambium Woody stem How old is this tree? vascular cambium late early xylem AP Biology phloem bark

Tree trunk anatomy tree girdling What does girdling do to a tree? AP Biology

Where will the carving be in 50 years? AP Biology

Global effects of plant growth What trends do you observe in global CO 2? AP Biology

Any Questions? ? Any Questions? AP Biology