| A | B |
|---|
| phloem | principle food conducting tissue – carbohydrates (sucrose mainly); also amino acids, hormones |
| sieve cells | more primitive (found in all vascular plant phyla) |
| sieve-tube members | only found in angiosperms |
| Golgi complexes | produce mucous for lubrication |
| amyloplasts | plastids with starch grains) used to perceive gravity |
| zone of cell division | apical meristem, cells divide every 12-36 hours |
| zone of elongation | cells get longer |
| zone of maturation | become specific cell types |
| epidermal cells | develop root hairs, where absorption occurs |
| cortex | parenchyma below epidermis |
| forms Casparian strips | walls of endodermis impregnated with suberin (fatty substance, impervious to moisture) |
| stele | all tissues interior to endodermis |
| pericycle | parenchymal layer just inside endodermis |
| primary xylem | forms star in core in most dicots, between arms or bundles of xylem |
| primary growth | just behind root cap |
| secondary growth | after formation of lateral meristems (cambia) |
| taproot system | one main root with branches |
| fibrous root system | many roots of similar diameter); there are several modified root types |
