Lecture 28: Monocots: Poaceae Flashcards

Question

Grass inflorescence

Answer 1

simple subunits called **spikelets** at base, there are **2 nodes with bracts** that are sterile (flowers not produced at these nodes) stem that forms the axis is called **rachilla** a **fertile bract attached to the node** of the rachilla is called a l**emma (**husk) bract at base of pedicel is **palea** (chaff)

Answer 2

highly condensed **branch of inflorescence with sterile bracts at base** called the 1st and 2nd **glume** stem that forms the axis is called **rachilla** a fertile bract attached to the node of the rachilla is called a **lemma (husk)**

Answer 3

a fertile bract attached to the node of the rachilla ## Footnote **lemma encloses palea;** **palea encloses flower**

Answer 4

bract at the base of the pedicel lemma encloses palea; palea encloses flower

Answer 5

each spikelet has 2 glumes at the base and 2 ranks of lemmas along the rachilla with each lemma enclosing a palea, which encloses a single flower

Answer 6

**perfect, hypogenous, actinomorphic** **Protoandrous** Perianth reduced (2-3 scale tepals called lodicules) 3 differentiated stamens compound pistil, superior ovary 2-3 styles (usually 2, with 2 carpels)

Answer 7

scale like tepals in grasses

Answer 8

lemma+palea+flower unit (kind of a misnomer) lemma and palea are derived from bracts, not the 4 floral series. functionally, lemma and palea are part of the floral unit

Answer 9

grain (caryopsis) 1-seeded, dry, indehiscent fruit **pericarp fused to seedcoat**

Answer 10

embryonic sporophyte develops towards the side of the **seed closest the lemma** **embryo is the germ of wheat,** corn and grains **fusion of matured ovary wall (pericarp) to the coat** makes a **bran** \ Dobule fertilization produces endosperm

Answer 11

structure formed when pericarp fuses to seed coat as in grains, the fruit of grasses aleurone layer of cells just inside the bran

Answer 12

nutritive tissue used by the developing embryo during germination and seedling establishment contains starch, proteins, fat, vitamins

Answer 13

cells just inside the bran rich in proteins and fats at germination, the layer secretes the enzymes that break down the endosperm starch into sugars that are absorbed by the germinating embryonic sporophyte

Answer 14

What 1 cotyledon in grass is called after it is modified by absorbing sugars released from the endosperm and transporting them to the sporophyte via phloem called scutellum in grasses

Answer 15

Industrial removal of aleurone layer of cells inside the bran (which are cells that break down endosperm) this leaves only the starchy endosperm makes white flower and rice, which has a long shelf life grains with germ have oils in embryo that become oxydized, esp. if they are crushed or ground up, tend to go rancid. but provide more balanced nutrition

Answer 16

When flower is almost mature, **lodicules swell,** **separating the lemma and palea filaments** elongate 1st so anthers emerge and release pollen styles then elongate, placing feathery stigmas into the **wind** to catch pollen as it passess **Protoandrous** flowers promote cross pollination

Answer 17

**Rush** stems are **round** in cross section with s**olid internods** **Sedge** stems are **triangular** with solid internodes **Grass** stems are round with **hollow internodes and flexible nodes that serve as joints** _Rushes are round, sedges have edges, and grass comes in joints_

Answer 18

cereals: wheat, barley, oats (near eastern cultures) rice (far east staple) sorghum and pearl millett (African) corn/maize (new world cultures) 70% of our farms are crop grasses, 50% of our calories come from grasses make breakfast cereals, breads, tacos, rice I**mportant derivatives**: corn starch, corn sweeteners, corn oil (margarine), livestock feed off grains **Grown for sap:** sugar cane (white sugar) molasses from stem of sorghum

Answer 19

grasses grown for their edible seeds

Answer 20

makes beer malt--germinated grain in which enzymes released from the aleurone layer have converted starch into sugars these are fermented using a fungus

Answer 21

rice wine, but really more like rice beer starts with polished rice (lacks aleurone layer) starch converted to sugars using 2 fungi! (so higher alc %) Aspergillus and cerevisiae fungi

Answer 22

whiskey made from barley rye (secale cereale) makes rye whiskey corn used to produce bourbon gin/vodka highly distilled from barley, grains, and potatoes (solanaceae) Gin is flavored with Cupressaceae juniper ovulate cones Rum is distilled from fermented sugar can/molasses

Answer 23

Tussock Grasses as ornamentals in lawn/garden bamboo used for houses, building and for matting for beds bamboo also used for eating (youmg shoots only), fiber for paper, and pulp for rayon

Answer 24

Height achieved by primary plant body due to structural organization of stem: strong fibers at perimeter, hollow internodes, enlarged, flexible nodes, that serve as joints to positiion the stem segments Segmented, hollow tube is strong, lightweight, and flexible This organization is similar (but altered) for many grasses bamboo used for houses, building and for matting for beds bamboo also used for eating (youmg shoots only), fiber for paper, and pulp for rayon