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Flashcards in Chapter 3 Deck (19):
1

Photosynthesis

The process by which light energy from the sun is converted to sugars

2

Transpiration

The loss/release of water vapor from the leaf by evaporation through the stomata

3

Respiration

Exchange of CO2(coming in) and Oxygen (going out)

4

Tendrils

A type of modified leaf that wrap around objects for support

Ex) Grape vines

5

Spines.

A type of modified leaf for protection

Thorns or spikes

6

Bracts

Green or colored leaves that surround flowers. Ex: Poinsettia

7

Mesophyll

(Parenchyma tissue)
'Middle' of the leaf. There are two types..

Palisade: contain most of the chloroplasts in dicot leafs

Spongy: next to the intercellular air spaces to allow for the interchange of gases.
Most monocots only have this type
Dicots have both

8

Vascular bundles

Tissues that transport materials to and from the leaf
(Xylem and phloem)

9

Epidermis

Outer layer of leaf. Upper and lower epidermis. It's translucent

Epidermal cells are clear to allow light penetration

10

Cuticle

Waxy layer usually produced by upper epidermis, also prevents moisture loss through epidermis

11

Stoma (stomata)

Opening in leaf; surrounded by two guard cells.
-stomata controls transpiration and air exchange rates

-mostly found in lower epidermis and occasionally in upper epidermis (for dicots)
-monocots have lower and upper stomata

12

Hydrathodes

Modified stoma

(Overflow holes)

-openings on leave margins at the end of veins that transpire water droplets instead of vapor

-this type of water secretion is called "guttation"

Often mistaken for dew

13

Trichomes

Hairlike projections that some leaves have.

For
•protection
•warmth in cold climates
•deflecting hot sun

Described at pubescence

14

Why are leafs green?

Chlorophyll is abundant in the leaf cells during the growing season

The chlorophylls green color dominates and masks out the colors of any pigment that may be present in the leaf

15

Why do leaves change in autumn?

• leaves lose chlorophyll as dormancy or death sets in (senescence)

• The chromoplast are always present in the leaf now show through and oranges reds purples yellows,etc.

16

Chromoplasts

Color plastid that are often found in many flower petals and fruits and dominate in some colored leaves

These are the non-green pigments

17

Leaf arrangements on the stem

•opposite-two leaves and auxiliary buds at the same node directly across from each other

•alternate-leaves and auxiliary bud's occur one per node on varying sides of the stem

•subopposite-almost opposite but a little Offset

•whorled-three or more leaves and auxiliary buds are attached at the same node

18

Petiole

The part that attaches the leaf to the stem

19

Blade of the leaf

The main part of the leaf that houses mesophyll