Stem is one of two main structural axes of vascular plants. Divided into nodes (leaf attachment points) and internodes. Contains dermal, ground, and vascular tissues
Pollen is a powdery substance produced by seed plants for sexual reproduction. Pollen grains contain male gametes and are protected by sporopollenin coating. Pollen grains vary in size from 2.5-5 μm to 90-100 μm in diameter
Inflorescence is a cluster of flowers arranged on a stem. Main axis above peduncle is called rachis. Pedicels are stalks of individual flowers. Inflorescences can be simple (single) or complex (panicle)
Transpiration is water movement through plants and evaporation from aerial parts. Plants lose 97-99.5% of water through transpiration and guttation. Water moves through xylem by cohesion and adhesion to foliage. Stomata control water loss through opening and closing
Endosperm is a triploid tissue produced in flowering plant seeds after double fertilization. Contains starch, oils, and protein for embryo nutrition. About 70% of angiosperm species have polyploid endosperm cells
Polyploidy occurs when cells have more than two sets of chromosomes. Most eukaryotic species are diploid, having two complete chromosome sets. Monoploids have only one set of chromosomes, like male bees