Following statements regarding to the embryogenesis in A. thaliana.

A. The first zygotic division is unequal, with the basal cell larger than the apical cell. The basal cell divides to give rise to the suspensor. The apical cell divides vertically to form a two-celled proembryo, which will give rise to the rest of the embryo.

B. The top most suspensor cell is recruited into the embryo, where it is known as the hypophysis, and contributes to the embryonic root meristem and root cap.

C. The next two divisions produce an eight-cell octant-stage embryo, which develops into a heart-stage embryo of around 32 cells

D. The embryo elongates and the cotyledons start to develop as wing-like structures at one end, while an embryonic root forms at the other. This stage is known as the globular stage.

Which of the following statements are correct?

#Question id: 10905

#Unit 6. System Physiology – Plant

The rate of movement of materials in the sieve elements can be expressed in two ways: as velocity, or as mass transfer rate. In early publications reporting on rates of transport in the phloem, what is the velocity and the mass transfer rate?

i) velocity-centimeters per hour (cm h^-1) and mass transfer- grams per hour per square centimeter (g h^-1 cm^-2)

ii) velocity-the linear distance traveled per unit time and mass transfer rate-the quantity of material passing through a given cross section of phloem or sieve elements per unit time.

iii) velocity- the quantity of material passing through a given cross section of phloem or sieve elements per unit time and mass transfer rate- the linear distance traveled per unit time

iv) velocity- per hour per square centimeter (h^-1 cm^-2) and mass transfer- kg centimeters per hour (cm h^-1)

#Question id: 10906

#Unit 6. System Physiology – Plant

The pressure-flow model explains phloem translocation as a flow of solution (bulk flow) driven by an osmotically generated pressure gradient between source and sink.

a) Phloem translocation, both active and passive mechanisms were considered. All theories, both active and passive, assume an energy requirement in both sources and sinks.

b) In sources, energy is necessary to move photosynthate from producing cells into the sieve elements. This movement of photosynthate is called phloem loading.

c) In sinks, energy is essential for some aspects of movement from sieve elements to sink cells, which store or metabolize the sugar. This movement of photosynthate from sieve elements to sink cells is called phloem unloading.

d) The Active mechanisms of phloem transport further assume that energy is required in the sieve elements of the path between sources and sinks simply to maintain structures.

From the given statements find out the correct for pressure-flow model.

#Question id: 10907

#Unit 6. System Physiology – Plant

The mechanism of phloem translocation in angiosperms is best explained by the pressure-flow model, this model is an example of,

#Question id: 10908

#Unit 6. System Physiology – Plant

The energy is necessary to move photosynthate from producing cells into the sieve elements. This movement of photosynthate is called

#Question id: 10909

#Unit 6. System Physiology – Plant

The energy is essential for some aspects of movement from sieve elements to sink cells, which store or metabolize the sugar. This movement of photosynthate from sieve elements to sink cells is called

#Question id: 10910

#Unit 6. System Physiology – Plant

In early research on phloem translocation, both active and passive mechanisms were considered. All theories, both active and passive, assume an energy requirement in both sources and sinks. What will be the INCORRECT explanation of active and passive mechanism?