Plant - Growth & Development Test 3

Cytokinin because its help in morphological grow kn plant tissue.

Geocarpy refers to the ripening of fruits underground, In the case of ground nut, the young fruits are pushed into the soil as a result of post-fertilisation curvature of the stalk.

Ethylene is a gaseous hormone. It aids in ripening of climacteric fruits and dehiscence of dry fruits. Climacteric fruits are the fleshy fruits which show a sudden sharp rise of respiration rate at the time of ripening (respiratory climacteric). They are usually transported in green or unripe stage. Ethylene is used to induce artificial ripening of these fruits e.g., Apple, Mango, Banana, etc.

Cytokinins are a group of hormones that promote cell division in plant roots and shoots and the growth of buds. Coconut milk is at times used in some tissue culture medium as it is rich in cytokinins.

Stomata open in response to light. In response to drought stress, plants synthesize the hormone abscisic acid (ABA), which triggers closing of stomatal pores. Therefore it is a correct match.
Gibberellic acid promotes growth and does not have any effect on leaf fall. Therefore it is not a correct match.
Cytokinins (CK) are a class of plant growth substances (phytohormones) that promotecell division or cytokinesis, in plant roots and shoots. Therefore it is a correct match.
Auxin induces rapid elongation growth of higher plants. The mechanism of auxinaction in the elongation growth acts on the cell walls. Therefore it is a correct match.

Ratio of cytokinins to auxins controls differentiation. If both of these are present in equal quantities, the cells divide but fail to differentiate. If there is more cytokinin than auxin, shoot buds develop. If there is more auxin than cytokinin, roots develop.

In botany, the cholodny-went model, proposed in 1927, is an early model describing tropism in emerging shoots of monocotelydons, including the tendencies for the shoot to grow towards light (phototropism) and the roots to grow downward (gravitropism). In both cases the directional growth is considered to be due to asymmetrical distribution of auxin, a plant growth hormone.
The Cholodny-Went theory states that plant tropisms in roots and shoots are due to the unequal distribution of the growth regulator auxin in reponse to light or gravity.

Movements in nyctinasty plants are not related to auxin levels. 

Nyctinasty is a type of tactic movement of a plant where the movement of plants organs like leaves occur in response to day and light and thus known as sleep movements. (Circardian rhythm) Eg in case of Acasia torcuosa, the movement of leaves occur horizontal during the day and vertical during the night. 

It is the movement of the plants' organs like roots towards the soil, sunflower tracking towards the sun which are regulated by the Auxin levels. So, the correct option is'Nyctinasty leave movements'. 

Scarification involves weakening, opening otherwise altering the coat of a seed to germination. Scarificationis often done mechanically, thermally, and chemically. The seeds of many plant species are often impervious to water and gases, thus preventing or delaying germination.

The hormones that delay senescence must decrease while the ones that speed up the aging process must increase. Cytokinins are one group of senescence delayers. These hormones are involved in cell growth, and high levels can help prevent senescence.

Phytohormones are growth regulators synthesized by plants and influencing physiological processes.
They are produced by plants and control or regulate germination, growth, metabolism, or other physiological activities. For example, Auxins, gibberellins, cytokinins, ethylene, and abscisic acid.
Hence Phytohormones are growth regulators synthesized by plants and influencing physiological processes.
So, the correct answer is 'Regulators synthesized by plants and influencing physiological processes'.

Gibberelin was 1st discovered in japan by kurusowa.He observed from his field that some of rice seedlings had grown much taller than others. on further observations he found that such taller rice plants had shown unusual internodal elongation.The internal elongation is known as bakane or foolish seedling disease of rice.Later it was discovered that elongation was due to a action of substance produced by fungusGibberella fujikuroi.The substance was successfully isolated from the fungus and it was named as gibberelic acid.

‘Foolish seedling’ of rice led to the discovery of GA.

Foolish seedling disease or Bakanae disease is a disease of rice seedlings, which was caused by a fungal pathogen . Kurosawa reported the appearance of symptoms of the disease in uninfected rice seedlings when they were treated with sterile filtrates of the fungus. The active substances were later identified as Gibberellic acid.