Activity No. 2.

Origin of the Plant Body

1. What is the first organ to be differentiated in mongo and castor oil seeds? Briefly explain the
reason for its emergence.
 The first organ to differentiate is the radicle. It ruptures the tesla after the softening of the
seed coat due to water absorbed and serves as an embryonic root.
2. Compare the mature embryos of the mongo and castor oil observed with corresponding seedlings.
 They both exhibited epigeal germination and in the castor oil beans, its cotyledons first
function as absorbing organs that facilitates the transfer food from the endosperm to the
rest of the seedling. The radicle of mongo was longer compared to the relative size of the
castor oil beans.
3. Give the precursor of the parts of the seedlings as observed in mongo and castor oil seeds.
 Radicle, epicotyl, hypocotyl, endosperm, foliage leaf, cotyledons
4. What is the first organ to be differentiated in rice and corn?
 Coleorhiza
5. How do the cotyledons originate from rice and corn seedlings?
 It originates from the precursor of SAM.
6. State the relation of the embryo to the mature plant from the point of view of developmental
morpho-anatomy, based on the following aspects
a. embryo and germination
 The germination starts when the radicle raptures the testa. It emerges and serves
as the embryonic root.
b. seedling phases
 As the seedlings germinates, parts are being developed. These parts include
radicle (embryonic root), hypocotyl (embryonic shoot), and cotyledons (seed
leaves). After the early stages of germination, the initial parts will later develop
and will serve as the shoot and root system of the plants.
c. adult vegetative phase and reproductive phase
 The adult vegetative phase of the plant has the capability of reproducing and in
the reproductive phase, there is a realization of reproductive structures.
7. What do you call the structure at the tip of the plant? What is the function of this structure?
 It is called the terminal bud and it is the primary growing point at the top of the stem.
8. Do you see the leaf axil, bud primordial and leaf primordial in the cabbage head? Explain.
 As observed in the pictures, the longitudinally halved cabbage head has the resemblance of
leaf axil, bud primordial and leaf primordial. I can’t completely state that I can see it since I
haven’t seen the specimen under the microscope.
9. Do you consider a cabbage head a twig? Justify your answer
 No, cabbage head is not a twig because a twig is recent-growth branches of trees or shrubs
10. Compare cabbage head with that of other monocot and dicot twigs.
 Monocot and dicot twigs have leaves in the side while in the cabbage head, it surrounds and
cover the stem.
11. What do you think is the function of the promeristem and the primary meristems?
 This refers to the young and imperfectly developed meristem which forms the first
foundation or beginning of an organ or a tissue.
12. In what region of the onion root tip do you see most of the mitotic stages? What is the function of
the quiescent center? Of the root cap?
  The region where most of the mitotic stages occur is in the meristematic region. The
quiescent center acts as a stem cell reservoir for the regeneration of the root apical meristem.
The root cap protects the root apical meristem.
13. What anatomical structures present in the shoot tip are absent from the root tip?
 Bud primordia and leaf primordia are only present in the shoot tip while in the root tip, it has
quiescent center.
14. What do the following terms mean?
a. Median section – cross-section that runs through the median plane
b. Periclinal cell wall – cell wall that arranged parallel to the surface of the plant
c. Plumule – primitive shoot of an embryo plant
d. Hypocotyl – below the cotyledon and develops into the first part of the stem where roots
will develop
e. Epicotyl – above the cotyledon and develops into the second part of the stem which bears
leaves, flowers, and roots
f. Mesocotyl – part of an embryo axis of a seedling above the scutellum and below the
coleoptile
g. Scutellum – the single cotyledon in the monocots that serves as an absorptive structure,
and their food reserves are stored elsewhere, in the endosperm
h. Suspensor – it transports nutrients to the growing embryo and pushes it into the lumen of
the endosperm.
i. Basal cell – it forms closest to the micropyle and gives rise to the suspensor
j. Apical cell – it is a cell that is found at the apex which is typically the origin of a
meristem
k. Hypocotyl-root axis – region from which the root will develop
l. Coleoptile – a leafy sheath which encloses the epicotyl of the embryo
m. Coleorhiza – a sheath that encloses the radicle of the embryo
n. Root primordial – site where lateral root may arise
o. Calyptrogen – meristematic cells of the root tip that give rise to the root cap.
p. Intercalary growth – a lengthwise growth in plants 
15. At what stage of embryo development do tissues become differentiated in the plant embryo?
 In the third week of fertilization
16. What is the precursor of the protoderm, procambium and ground meristem?
 Protoderm comes from tunica while procambium and ground meristem were from the corpus.
17. What is primary growth? Secondary growth?
 Primary growth refers to the plant growth derived from the tissues of apical meristems while
the secondary growth is the growth that originated from the vascular cambium and
responsible for the increase in girth.
18. How will you define a lateral meristem?
 It is responsible for the lateral growth of plants.
19. How do you explain growth, morphogenesis, and differentiation?
 Growth is the increase in size, morphogenesis refers to the development of the forms in living
organisms, and differentiation is the process by which cells become specialized into different
types.