BIOL 1050 Lecture Notes - Lecture 2: Viviparity, Zygote, Endosperm
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Primary root replaced by adventitious roots (quickly replaced with roots that arise from the stem) Primary root can persist (tap root) primary root goes to the stem. Sexual reproduction: pla(cid:374)ts ha(cid:448)e a p(cid:396)o(cid:271)le(cid:373): they a(cid:396)e(cid:374)"t (cid:373)o(cid:271)ile, the sporophytes cannot move around to find a mate, they have adapted various strategies, to move male gametes around, to disperse seeds (fruits) Callose: beta 1,3 linkages molecule forms a helix. Cellulose: beta 1,4 linkages linear polymer. Pollen wide array of types and sizes: can identify species from pollen, species specific, range from 0. 006mm to over 0. 1mm, out coating (exine) consists of different patterns and composed of sporopollenin. Sporopollenin: co(cid:373)pou(cid:374)d o(cid:374) outside of polle(cid:374) (cid:894)u(cid:374)k(cid:374)o(cid:449)(cid:374) (cid:271)/(cid:272) (cid:272)a(cid:374)"t (cid:271)e (cid:271)(cid:396)oke(cid:374) do(cid:449)(cid:374)(cid:895, extremely resistant to degradation, physical, biological, and chemical degradation, helps protect pollen in harsh environments, among most chemically inert polymers, unknown composition, likely diverse and multicomponent.