Ethylene Questions in English

(D) Ethylene is a gaseous plant hormone that is primarily synthesized in large quantities by tissues undergoing senescence and ripening fruits. It acts as a plant growth regulator that promotes the ripening process of fruits.

(B) Ethylene is a simple gaseous plant growth regulator. It is synthesized from the amino acid methionine,not from carotenoids. Abscisic acid $(ABA)$ is the plant hormone derived from carotenoids. Therefore,option $B$ is incorrect.

(A) The triple response is a classic physiological effect observed in etiolated pea seedlings treated with ethylene. It consists of three distinct components: $1.$ Inhibition of stem elongation,$2.$ Promotion of lateral expansion (swelling) of the stem,and $3.$ Horizontal growth (loss of normal geotropic orientation).

(C) $CH_2 = CH_2$ is the chemical formula for ethylene. Ethylene is a gaseous plant hormone that plays a crucial role in the ripening of fruits by accelerating the process.

(N/A) Ethylene is a simple gaseous $PGR$.
It is synthesized in large amounts by tissues undergoing senescence and ripening fruits.
Influences of ethylene on plants include horizontal growth of seedlings,swelling of the axis,and apical hook formation in dicot seedlings.
Ethylene promotes senescence and abscission of plant organs,especially of leaves and flowers.
Ethylene is highly effective in fruit ripening.
It enhances the respiration rate during the ripening of fruits.
This rise in the rate of respiration is called respiratory climacteric.
Ethylene breaks seed and bud dormancy,initiates germination in peanut seeds,and sprouting of potato tubers.
Ethylene promotes rapid internode/petiole elongation in deep-water rice plants.
It helps leaves/upper parts of the shoot to remain above water.
Ethylene also promotes root growth and root hair formation,thus helping the plants to increase their absorption surface.
Ethylene is used to initiate flowering and for synchronizing fruit-set in pineapples.
It also induces flowering in mango.
Since ethylene regulates so many physiological processes,it is one of the most widely used $PGR$ in agriculture.
Ethephon in an aqueous solution is readily absorbed and transported within the plant and releases ethylene slowly.
Ethephon hastens fruit ripening in tomatoes and apples and accelerates abscission in flowers and fruits (thinning of cotton,cherry,walnut).
It promotes female flowers in cucumbers,thereby increasing the yield.

(D) The influences of ethylene on plants include the horizontal growth of seedlings,swelling of the axis,and apical hook formation in dicot seedlings.
Ethylene promotes senescence and abscission of plant organs,especially of leaves and flowers.
Ethylene is highly effective in fruit ripening.

(C) Ethylene is a gaseous plant hormone. It is primarily responsible for the ripening of fruits.
- Ethylene also plays a major role in determining the sex of monoecious flowers and is associated with the promotion of femaleness in plants.
- Therefore,the farmer must spray the ethylene hormone on his cucumber crop to produce more female flowers and increase the yield.

(A) The gaseous plant growth regulator is $Ethylene$.
$Ethylene$ is known for its role in promoting root growth and root hair formation,which helps in increasing the absorption surface area of the roots.
Option $A$ is correct because $Ethylene$ specifically stimulates root growth and root hair development.
Option $B$ is a function of $Cytokinins$.
Option $C$ is a function of $Auxins$ (e.g.,$2,4-D$).
Option $D$ is a function of $Gibberellins$.

(B) Ethylene is a gaseous plant hormone that plays a crucial role in various physiological processes. One of its most significant agricultural applications is its ability to promote the formation of female flowers in monoecious plants like cucumber. By increasing the number of female flowers,the fruit set and overall yield of the crop are significantly enhanced. Therefore,the application of ethylene is widely used in commercial cucumber cultivation to increase production.

(B) The plant growth regulator $Ethylene$ is unique because it acts as both a growth promoter and a growth inhibitor.
It promotes processes such as fruit ripening,senescence of leaves and flowers,and abscission.
However,it also inhibits longitudinal growth in stems and roots,and it is primarily known for its role in inhibiting growth in many physiological contexts,making it a versatile regulator.

(D) Ethylene is a simple gaseous plant growth regulator. It is synthesized in large amounts by tissues undergoing senescence and ripening fruits. It promotes horizontal growth of seedlings,axis swelling,and apical hook formation in dicot seedlings.

(C) Ethylene is a gaseous plant hormone that plays a crucial role in various physiological processes. One of its well-known functions is the promotion of sprouting in potato tubers. It breaks the dormancy of the buds,thereby facilitating the growth of new shoots from the tubers.

(D) Ethephon is a widely used source of ethylene.
$1$. It is supplied in an aqueous solution,which is readily absorbed and transported within the plant,and it releases ethylene slowly.
$2$. It hastens fruit ripening in tomatoes and apples and accelerates abscission in flowers and fruits.
$3$. It promotes female flowers in cucumbers,thereby increasing the yield.
Therefore,all the given statements are correct.

(D) Ethylene is a gaseous plant hormone that plays a crucial role in the ripening of fruits.
It promotes the breakdown of cell walls,the conversion of starch into sugars,and the degradation of chlorophyll,which leads to the softening and sweetening of fruits.
Therefore,it is widely used in agriculture to induce uniform ripening of climacteric fruits.

(D) Ethylene is a gaseous plant hormone that plays a crucial role in the growth and development of plants.
In deep-water rice plants,ethylene promotes rapid internode and petiole elongation.
This adaptation allows the leaves and upper parts of the plant to remain above the water surface,ensuring continued gas exchange and photosynthesis even during flooding.
Therefore,the correct option is $D$.

(D) Ethylene is a gaseous plant hormone that plays a crucial role in the growth and development of plants.
In deep water rice plants,ethylene promotes rapid internode and petiole elongation.
This adaptation allows the leaves and upper parts of the plant to remain above the water surface,ensuring continued gas exchange and survival during flooding conditions.

(A) The triple response is a classic physiological response observed in etiolated pea seedlings when exposed to ethylene.
It consists of three distinct morphological changes:
$1$. Inhibition of stem elongation.
$2$. Increased lateral expansion (swelling) of the stem.
$3$. Horizontal growth (diageotropism) of the stem instead of vertical growth.
Therefore,ethylene is the hormone responsible for the triple response.

(B) In deep water rice plants,the hormone $Ethylene$ plays a crucial role in survival during flooding.
When the plant is submerged,$Ethylene$ accumulates in the tissues.
This accumulation promotes rapid internode and petiole elongation,allowing the leaves and upper parts of the plant to remain above the water surface for gas exchange and photosynthesis.

(C) Ethylene is a gaseous plant hormone that plays a crucial role in various physiological processes.
It promotes horizontal growth of seedlings,swelling of the axis,and the formation of an apical hook in dicot seedlings.
These effects are characteristic of the 'triple response' induced by ethylene,which helps the seedling navigate through soil obstacles.
Therefore,the correct option is $C$.

(A) Ethylene is a gaseous plant hormone that plays a crucial role in various physiological processes.
In cucumber plants,ethylene is known to increase the number of female flowers.
It is widely used in agriculture to induce flowering and promote the development of female flowers,thereby increasing the yield of fruits.

(A) Ethylene is a gaseous plant hormone that plays a crucial role in various physiological processes. In cucumber plants,ethylene is known to promote the formation of female flowers,thereby increasing the yield of fruits. This is a classic example of the role of plant growth regulators in sex expression.

(D) Plant hormones are broadly categorized into growth promoters and growth inhibitors.
$1$. Growth promoters include Auxins,Gibberellins,and Cytokinins,which stimulate cell division,elongation,and growth.
$2$. Growth inhibitors include Ethylene and Abscisic Acid $(ABA)$,which inhibit growth and promote senescence or dormancy.
Therefore,Ethylene is classified as a growth inhibitor,not a growth promoter.

(A) Ethylene is a simple gaseous plant growth regulator. It is synthesized in large amounts by tissues undergoing senescence and ripening fruits. It is widely used in agriculture for the ripening of fruits like tomatoes and apples.

(D) Ethylene is the only known gaseous plant hormone.
It is primarily involved in the ripening of fruits and the senescence of plant organs.
Other hormones like $ABA$,$Gibberellins$,and $Auxin$ are not gaseous in nature.

(D) Abscission layer formation is accelerated by ethylene.
Ethylene is the only gaseous plant hormone associated with fruit ripening.
It promotes the formation of the abscission layer in leaves,flowers,and fruits,leading to their shedding.
Additionally,it breaks the dormancy of buds and seeds and helps in the formation of lateral roots.

(B) Ethylene is a gaseous plant hormone known to promote senescence and fruit ripening.
During the process of fruit ripening,there is a sudden increase in the rate of respiration,a phenomenon known as the respiratory climacteric.
Ethylene triggers this rise in respiration,which provides the energy required for the metabolic changes associated with ripening.

(D) Ethylene is a simple gaseous plant hormone. It is synthesized in large quantities by tissues undergoing senescence and ripening fruits. However,it is produced in almost all parts of a plant,including leaves,stems,roots,flowers,and fruits,to regulate various physiological processes such as fruit ripening,senescence,and abscission. Therefore,it is considered to be produced in almost all parts of the plant.

(D) $2$-chloroethylphosphonic acid,commonly known as $Ethrel$,is used to promote synchronized flowering in pineapples.
It acts as an ethylene-releasing compound,which induces flowering.