Plant Growth and Hormones

Morphactins include several synthetic fluorine-containing compounds that tend to produce morphological changes and suppress the growth in plants.

Auxin is synthesised in apical meristems of shoots. 

 Gibberellic acid was first isolated from Giberella fujikuroii.

 The correct answer is  Impatiens.

  90 gibberellins have been isolated so far.

Ethylene is widely used in the ripening of fruits.

Impatiens balsamina is a well-documented short-day plant that responds to gibberellin treatment by flowering under non-inductive conditions. While Xanthium, Dahlia, and Biloxi soybean are all short-day plants, Impatiens balsamina is specifically mentioned in botanical literature as responding to gibberellins for flowering induction, making it the correct answer.

The Avena coleoptile curvature test is a specific bioassay developed by F.W. Went and others to detect and quantify auxins (indole-3-acetic acid and related compounds). When auxin is applied asymmetrically to a decapitated oat coleoptile, it causes cell elongation and curvature proportional to the auxin concentration. This test is not specific for gibberellins, cytokinins, or abscisic acid, which have different bioassays.

Cytokinins promote cell division and they are present in areas of fruits and seeds, which requires greater cell division.

Cytokinins are plant hormones that specifically promote cell division (cytokinesis) and are involved in promoting root formation in tissue culture. They work in conjunction with auxins - high cytokinin to auxin ratio promotes shoot formation, while low ratio (more auxin) promotes root formation. However, cytokinins themselves are directly associated with promoting root initiation in tissue culture experiments. Options A, B, and D are not the primary functions of cytokinins.

 Sprouting of dormant buds of a potato tuber can be induced by GA.

Cytokinins are concentrated in regions of active cell division: embryos (rapidly dividing), developing fruits (cell expansion and division), and root tips (apical meristems). This distribution reflects their primary role in promoting cytokinesis. While present in other tissues, the highest concentrations are found in these metabolically active regions.

Gibberellic acid (GA) is a plant hormone that stimulates the production of alpha-amylase enzyme in the aleurone layer of barley seeds during germination. This enzyme breaks down starch into sugars, providing energy for the growing embryo. Pectinase, cellulase, and protease are not induced by GA in this context.

Cytokinins are plant hormones that delay senescence (aging) by promoting cell division and preventing protein degradation. They act as anti-aging hormones in plants. Gibberellins promote elongation, auxins regulate growth, and ethylene promotes ripening and senescence.

Cytokinins (CK) are a class of plant growth substances (plant hormones) that promote cell division, or cytokinesis, in plant roots and shoots. These are primarily involved in cell growth and differentiation, but also affect apical dominance, axillary bud growth, and leaf senescence.