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GENERAL BOTANY: SEEDS
Ballon vine, seeds with a heart SEEDS MORPHOLOGY ➔ Embryo: enclosed by a hard protective seed coat ➔ Dicot seeds have hypocotyl, radicle and thick cotyledons ➔ Hypocotyl: the axis below cotyledon attachment point and above radicle ➔ Epicotyl: embryonic axis above point of embryonic attachment ➔ Radicle: embryonic root ➔ Microypyle: where the embryo with develop, entry point of water ➔ Chalaza: basal part of the seed/ovule in plants, where nucleus and integuments join
- castor beans have a similar seed structure but thin cotyledon – deadliest beans, 6000 times more poisonous than cyanide, 120000 times more poisonous than rattlesnake venom
MONOCOT SEEDS
➔ Embryo of a monocot seeds has a single cotyledon, a coleoptile, and a coleorhiza SEED GERMINATION Hypogeal or Cryptocotylar in MONOCOTS Hidden cotyledons when the plant matures Epigeal or Phanerocotylar in DICOTS Cotyledons shrivle or exposed outside when the plant matures @9013cm – do not replicate, copy, or distribute without permission
GENERAL BOTANY: SEEDS
SEEDLESS FRUITS
➔ Pollination failure: self-incompatible oranges–associated with pollen if it is delivered to a stigma too little, too much, too late, too mixed in composition or too poor in quality ➔ Chromosomal imbalance: bananas (3n), seedless watermelons from 2n x 4n parents ➔ Application of auxin–growth hormone promoting cell division in plants: tomato and cucumbers when auxin applies before the seed matures can promote parthenocarpy MEANS OF ASEXUAL REPRODUCTION ➔ Fragmentation: separation of a parent plant into parts that develop into whole plants ➔ Apomixis: asexual reproduction of seeds – a diploid cell in the ovule develops into an embryo which mature into a seed ➔ Vegetative Propagation: produces plants that are exact replicas of the mother tree ◆ Root Cuttings: rimas ◆ Stem Cuttings: gumamela, santan ◆ Leaf cuttings: black pepper, sanseviera, begonia ➔ Grafting: involves joining the stock (mother plant) with a choice of variety ◆ Union of cambium layers of stock anf scion ◆ The scion must be kept alive until the union been effected ASEXUAL REPRODUCTION AND AGRICULTURE ➔ Main Disadvantage: no genetic variation ➔ Nearly all of today’s crop plants have very little genetic variation ➔ Monocultures: large areas of land with one specie @9013cm – do not replicate, copy, or distribute without permission
