Plant Development and Morphology

Question 1

What are the steps from seed to germinations ?

Answer 1

1- Seeds result from pollination, formation of a zygote and embryo development inside the flower.
2. A highly controlled series of cell divsions from the initial zygote results in an embryo plant.
3. The seed contains an embryo plant and storage molecules that help drive germination

Question 2

Draw what the embryo development in Arabidopsis looks like ?

Answer 2

1- Egg
2. Two cell
3. Octant
4.Globular
5.Triangular
6.Heart
7. Torpedo
8. Mature embryo

Question 3

What occurs to the seed to produce a seedling ?

Answer 3

At seed germination, the radicle ( young root ) emerges from the seed.
2. This is now a seedling

Question 4

What are meristems ?

Answer 4

All new cells for expanding structures are generated at two specialised regions called MERISTEMS - one in the shoot and one in the root.

Question 5

What causes young seedlings to be polar ?

Answer 5

The root is at the bottom beneath the HYPOCOTYL ( stem of a seedling ) and the COTYLEDONS ( seed leaves )

Question 6

What is the upper part and lower part of the stem related to ?

Answer 6

1. The upper part is related to light capture in the air ( and is green )
2. The lower part is related to water and nutrient and uptake and stability in the soil

Question 7

What is the shoot apical meristem of an Arabidopsis seedling ?

Answer 7

Thin section cut in fixed embedded seedling and stained with DAPI, a white - blue fluorescent marker that stains DNA

Question 8

What produces a shoot in a seedling ?

Answer 8

Only the hypocotyl and cotyledons are present in the embryo. The shoot apical meristem generates all the other above-ground organs

Question 9

What is phyllotaxy ?

Answer 9

This precise patterning of leaf primordia around the meristem dectates the pattern of leaves in the mature plant

Question 10

What are the 5 types of phyllotaxis ?

Answer 10

1- alternate
2- distichous
3- opposite
4- decussate
5- whorled

Question 11

How come monocot leaves have only one typr of mesophyll cell ?

Answer 11

Since their leaves are positioned more vertically and there is little distinction between the upper and lower leaf surface

Question 12

Whats the 6 type of leaves of monocot crop species ?

Answer 12

1- Maize
2- Barley
3-Sorghum
4- Sugarcane
5- Wheat
6- Rice

Question 13

Whats inflorescenes ?

Answer 13

1. Inflorescences are the structures on which flowers, the reproductive organs of angiosperms, are borne.

Question 14

Whats the sexuality of flowers ?

Answer 14

Most flowers are bisexual, with the female sex organs including the ovules within the carpel and the male sex organs within the stamens

Question 15

What are Mesophytes ?

Answer 15

includes most temperate and tropical plants
Growing conditions with reasnoable temperatures and good supply of water
Include almost all of the worlds crop plants

Question 16

What are Xerophytes ?

Answer 16

1. Plants adapted to harsh, dry environments
2. Thick cuticles, reduced surface/volume ratios and shallow roots
3. Often store water in their leaves or stems and open their stomata only at night
4. Several plant families are xerophytic ( succulents ), the cacti exclusively so

Question 17

What are Hydrophytes ?

Answer 17

1. Land plants that have evolved to reinvade the water
2. Some float on the surface, some are semi-submerged, some are fully aquatic
3. Freshwater and marine