Chapter 15

Assertion: Plant retains the capacity for unlimited growth throughout their life. Reason: This ability of the plants is due to the presence of meristem at certain location of body.

Assertion: A sigmoid curve is a characterstic of living organism growing in a natural environment. Reason: Sigmoid curve is an S shaped curve.

Assertion: GA increase the yield in sugarcane. Reason: GA causes increase in length of sugarcane stem.

Assertion: Cytokinin delays the leaf senescence. Reason: Cytokinin promotes nutrient mobilization.

Assertion: ABA increases the tolerance of plant to various kinds of stresses. Reason: ABA stimulates the closure of stomata in the epidermis.

Assertion: Ethylene increases the yield in cucumber. Reason: Ethylene promotes female flower in cucumber.

Assertion: Ethylene increases the yield in cucumber. Reason: Ethylene promotes female flower in cucumber.

Assertion: Vernalization refers specially to the promotion of flowering by a period of low temprature. Reason: Vernalization also seen in biennial plants.

Assertion: Auxins have been used extensively in agriculture and horticulture. Reason: They help to initiate rooting in stem cuttings.

Assertion: A plant hormone is a growth regulator. Reason: Growth regulators promote or inhibit the growth.

Assertion: Expansion of a leaf is growth. Reason: It is irreversible process

Assertion: Plant posses open form of growth Reason: Plant has meristmetic tissues

Assertion: Growth in plant is measurable Reason: We can measure growth of pollen tube in terms of its length

Assertion: Secondary xylem is example of redifferentiated cells. Reason: Secondary xylem develops from dedifferentiated cells.

Assertion: In tea plantation hedge making is occur by decapitation. Reason: Removal of apical bud usually results in the growth of lateral buds.

Assertion: \(\mathrm{GA}_{3}\) is used to speed up the melting process in brewing industries Reason: \(\mathrm{GA}_{3}\) leads to synthesis of \(\alpha\) -amylase hydrolysing enzyme which is responsible for partial hydrolysis of starch.

Assertion: Generally plant without leaf is unable to produce flower Reason: Leaves are site of perception of light for flowering

Assertion: ABA is known as stress hormone Reason: ABA increases the tolerance of plants to several kinds of stresses.

Assertion: \(2,4 \mathrm{D}\) is selective weedicide Reason: \(2,4 \mathrm{D}\) is widely used to kill dicotyledonous weeds and doesn't affect mature monocotyledonous plant.

Assertion: GAs leads to early seed production in conifers Reason: GAs hastens maturity period in juvenile conifers.

Assertion: Ethylene helps the plants to increase their surface area for absorption. Reason: Ethylene promotes root growth and root hair formation.