module 4

Question 1

In an oil palm crop:

(A) higher than normal plant density would reduce annual fruit yield/hectare;

(B) lower than normal plant density would cause the trees to gain height faster, and therefore shorten the plantation’s economic life;

(C) the fruit are similar to dates;

(D) the crop is unresponsive to plant density variation;

(E) all of the above are false.

Answer 1

(E) all of the above are false.

Question 2

Self-thinning rule

Answer 2

If a population of plants is allowed to grow bigger with time there is eventually a critical point where further size increase is necessarily accompanied by the death of some members of the population

Question 3

The self-thinning rule:

(A) has been referred to as ecology’s law in search of a theory;

(B) indicates that on a logarithmic scale increase in plant weight in a forest or crop is typically associated with an increase in plant density;

(C) can be intuitively understood from considerations of soil nutrient status;

(D) is only applicable to newly sown stands of plants before canopy closure, and not to mature stands;

(E) is only applicable in situations where plants are crowded.

Answer 3

(E) is only applicable in situations where plants are crowded.

or

(A) has been referred to as ecology’s law in search of a theory;

Question 4

Cross sowing:

(A) utilises double the amount of seeds compared to a single seeding line;

(B) is cheaper than a single seeding line system;

(C) utilises the same amount of seed as a single seeding line;

(D) requires better seedbed preparation than a single seeding line;

(E) utilises a minor amount of seed compared to a single seeding line.

Answer 4

(C) utilises the same amount of seed as a single seeding line;

Question 5

Tillering allows:

(A) compensatory growth when a low percentage of plantlets establish;

(B) competition only with other plant species nearby but not with plants of the same species;

(C) a better rhizobia-plant interaction;

(D) the growth of a deeper rooting system;

(E) a larger seed production all the time.

Answer 5

(A) compensatory growth when a low percentage of plantlets establish;

Question 6

Consequences of the self-thinning rule are:

(A) a reduction of the total pasture yield;

(B) increasing plant size causes no decrease in plant density;

(C) with increasing density in trees there is an increase in the number of branches per metre of trunk;

(D) grasses will grow closer to the ground;

(E) as individual plant size increases, plant numbers decrease

Answer 6

(E) as individual plant size increases, plant numbers decrease

Question 7

“Umbrella effect”:

Answer 7

: longer leaves than other grass speciesThus, in absence of grazing: neighbours killed by shading from cocksfoot leaves.

Question 8

A plant competitor is a plant:

(A) that dominates a site due to its tolerance to environmental stress

(B) that occupies areas because it can avoid grazing;

(C) species that grows very slowly;

(D) specialised at capturing resources;

(E) species that requires a high level of environmental resources.

Answer 8

(D) specialised at capturing resources;

Question 9

The function of a white clover stolon is to:

(A) increase the survival probability of an individual plant;

(B) allow an increase in the area explored by an individual plant;

(C) keep the growing points under defoliation height;

(D) all the above are true;

(E) only A and C are true.

Answer 9

(D) all the above are true;

Question 10

In newly sown grass swards facing a similar intensity of root or shoot competition, which type of competition (root or shoot) would be expected to result in the greatest reduction in plant size? ……………..

Answer 10

root

Question 11

The Netherlands’ scientist credited with developing the concept of replacement series diagrams to help describe plant competition interactions between crop species was named ……

Answer 11

de wit

Question 12

In the resource ratio hypothesis of plant competition developed by Grime and attributing C, S, R strategies what do c and r and s stand for

Answer 12

s: stress tolorators
c: copetitors
r: rudelars

Question 13

What is endophyte?

Answer 13

A fungus, living within some grass plants • Symbiotic, not parasitic

Question 14

Wild-type ryegrass endophyte fungi can produce the alkaloid, .………………, that causes ryegrass staggers in grazing animals.

Answer 14

Lolitrem

Question 15

Name one (1) alkaloid toxic to Argentine stem weevil produced by perennial ryegrass endophyte: .……………….

Answer 15

Peramine (an alkaloid)