Ethylene Questions in English

(D) The correct answer is $D$. Apples are climacteric fruits that produce large amounts of the gaseous plant hormone ethylene $(C_2H_4)$. Ethylene is a natural plant growth regulator that promotes the ripening process in fruits. When an apple is placed in a bag with an unripe banana,the ethylene gas released by the apple accumulates in the bag and triggers the ripening process in the banana,causing it to turn yellow.

(A) In many plants,there is a sharp increase in the respiration rate near the end of fruit development. This sudden rise in respiration is known as the 'climacteric rise' or 'climacteric'. This process triggers the biochemical changes involved in fruit ripening.

(A) Ethylene and its precursors like $NAA$ (Naphthalene Acetic Acid) are widely used in agriculture to induce flowering in pineapple plants.
While ethylene generally inhibits flowering in most plants,it acts as a potent promoter of flowering in pineapple,allowing for off-season production.

(D) Ethylene $(C_2H_4)$ is a simple gaseous plant hormone.
It is an unsaturated hydrocarbon.
Its primary physiological effect is the promotion of fruit ripening.
It accelerates the maturation of fruits and induces early ripening in many fruits like apples,bananas,and tomatoes.

(B) Ethylene is a simple gaseous plant growth regulator. It was recognized as a natural plant hormone by $Crocker$ in $1934$. He demonstrated that ethylene is produced by ripening fruits and can induce fruit ripening in other fruits.

(A) Ethylene is a gaseous plant hormone.
It plays a crucial role in various physiological processes such as fruit ripening,senescence,and abscission.
It is known to stimulate transverse or isodiametric growth while retarding longitudinal growth.

(A) Ethylene is a gaseous plant hormone that promotes fruit ripening.
Among the given options,a ripening banana produces a significantly higher amount of ethylene compared to green fruits or tubers,as it acts as an autocatalytic agent to accelerate the ripening process.

(C) The ripening of fruits,including bananas,is primarily regulated by the plant hormone ethylene.
During the ripening process,there is a significant and sudden increase in the production of ethylene,which acts as a gaseous plant growth regulator to trigger the physiological changes associated with ripening,such as softening,color change,and sugar accumulation.

(D) $Ethylene$ is a gaseous plant hormone that plays a crucial role in the ripening of fruits.
It promotes the breakdown of cell walls and the conversion of starches into sugars,thereby accelerating the ripening process.
Therefore,treatment with $Ethylene$ gas is commonly used in agriculture to hasten fruit ripening.

(A) The term 'phytogerontological' refers to the study of aging in plants.
Ethylene is a plant hormone that promotes senescence (aging) and abscission of plant organs such as leaves and flowers.
Because it accelerates the aging process in plants,it is commonly referred to as the phytogerontological hormone.

(C) Ethylene is a gaseous plant hormone known for its role in various physiological processes.
$1$. It promotes the ripening of fruits by accelerating the respiratory rate (climacteric respiration).
$2$. It increases the number of female flowers in plants like cucumber.
$3$. It promotes the abscission of leaves,flowers,and fruits.
$4$. It inhibits cell elongation in stems and roots.
Therefore,the correct response is the increase in the ripening of fruits.

(D) Artificial ripening is a process used to accelerate the maturation of climacteric fruits,which continue to ripen after being harvested. Fruits like $Mango$,$Banana$,and $Grapes$ are climacteric and respond to ethylene treatment. However,$Pomegranate$ and $Coconut$ are non-climacteric fruits. Non-climacteric fruits do not produce significant amounts of ethylene and do not ripen further once harvested; therefore,artificial ripening treatments are ineffective and useless for them.

(B) $Ethylene$ is a gaseous plant hormone that plays a crucial role in fruit ripening.
In most plants,there is a sharp increase in the rate of respiration during the process of fruit ripening.
This sudden rise in the respiration rate is known as the $climacteric$ rise or $climacteric$ respiration.
Therefore,ethylene is responsible for inducing this climacteric respiration.

(A) Ethylene $(C_2H_4)$ is a gaseous plant hormone that promotes fruit ripening.
In commercial applications,a mixture containing $80\% \ C_2H_4$ and $20\% \ CO_2$ is often used to accelerate the ripening process of fruits.
Therefore,the correct combination is $80\% \ C_2H_4$ and $20\% \ CO_2$.

(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 to sugars,and the degradation of chlorophyll,which leads to the softening,sweetening,and color change associated with fruit ripening. Therefore,the correct answer is $Ethylene$.

(D) The correct answer is $D$.
Ethylene is a gaseous plant hormone that plays a significant role in plant growth and development.
In many plants,including pea seedlings,ethylene inhibits longitudinal (vertical) growth while simultaneously stimulating transverse (horizontal) growth.
This effect leads to a characteristic 'stunted' or thickened appearance of the stem,which is part of the 'triple response' to ethylene.

(D) The correct answer is $D$. Ethylene is a gaseous plant hormone that plays a crucial role in the ripening of fruits. It is widely used in agriculture to accelerate the ripening process of climacteric fruits such as bananas,mangoes,and tomatoes. By artificially adding ethylene gas to the storage environment,the rate of fruit ripening is significantly increased.

(A) Ethylene is a gaseous plant hormone known for its role in promoting the ripening of fruits. It accelerates the ripening process by stimulating the breakdown of cell walls and the conversion of starches into sugars. Therefore,it is widely used in agriculture to induce uniform ripening of climacteric fruits like bananas,mangoes,and tomatoes.

(C) Ethylene is a gaseous plant hormone that plays a crucial role in the ripening of fruits.
It is widely used in agriculture to induce artificial ripening in climacteric fruits like bananas,mangoes,and tomatoes by accelerating the physiological processes involved in fruit maturation.

(D) Ethylene $(C_2H_4)$ is a gaseous plant hormone that promotes fruit ripening. In industrial or artificial fruit ripening processes,a mixture containing ethylene gas is often used to accelerate the process. Option $D$ represents a mixture containing ethylene $(C_2H_4)$ and carbon dioxide $(CO_2)$,which is commonly associated with controlled atmosphere storage or ripening conditions.

(C) Ethylene is a gaseous plant hormone that plays a crucial role in various physiological processes. One of its primary functions is to break the dormancy of seeds and buds, including potato tubers. It promotes sprouting by overcoming the inhibitory effects of other hormones like $ABA$ (Abscisic Acid). Therefore, Ethylene is used to break the dormancy of potato tubers.

(C) Ethylene is a simple gaseous plant hormone. It is widely used in agriculture to promote the ripening of fruits such as bananas,mangoes,and tomatoes. It accelerates the ripening process by stimulating the breakdown of starch into sugars,which increases the sweetness and juiciness of the fruit. Therefore,$Ethylene$ $gas$ is the correct answer.

(D) The correct answer is $D$.
Ethylene is a gaseous plant hormone that plays a crucial role in root development.
It promotes root growth and the formation of root hairs,which increases the surface area for water and mineral absorption.
In low concentrations,ethylene is specifically used for the initiation of roots and the development of lateral roots.

(D) Ethylene is a simple gaseous plant growth regulator $(PGR)$.
It is classified as a plant hormone because it is synthesized in various parts of the plant and regulates physiological processes such as fruit ripening,senescence,and abscission.
Therefore,the correct option is $D$.

(C) Ethylene is a gaseous plant hormone that plays a crucial role in the ripening of climacteric fruits such as tomatoes and apples. It promotes the breakdown of cell walls,the conversion of starch to sugars,and the degradation of chlorophyll,which accelerates the ripening process.

(D) Plant hormones are classified 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 Abscisic acid and Ethylene.
$3$. Ethylene is primarily known as a growth inhibitor because it promotes senescence and abscission of plant organs,although it also plays a role in fruit ripening.
Therefore,among the given options,Ethylene is the growth inhibitor.

(C) Ethylene is a simple gaseous plant hormone.
It is synthesized in large amounts by tissues undergoing senescence and ripening fruits.
It influences horizontal growth of seedlings,axis swelling,and apical hook formation in dicot seedlings.
It is widely used in agriculture for the ripening of fruits like tomatoes and apples.

(C) Ethylene is a gaseous plant hormone that plays a crucial role in various physiological processes.
It is primarily known for its role in promoting the ripening of climacteric fruits such as bananas,mangoes,and tomatoes.
It accelerates the respiration rate during the ripening process,leading to changes in color,texture,and flavor.
Therefore,it is widely used in agriculture to induce uniform ripening of fruits.

(B) The $PGR$ discovered by $R. Gane$ (confirmed by $Cousins$) is $Ethylene$.
$Cousins$ discovered that the release of a volatile substance from ripened oranges hastened the ripening of stored unripened bananas.
This volatile substance was later identified as $Ethylene$.
$Ethylene$ is a simple gaseous $PGR$.

(C) The respiratory climacteric refers to the sudden increase in the rate of respiration during the ripening process of certain fruits.
Ethylene is the plant hormone responsible for regulating this process.
It promotes fruit ripening and triggers the climacteric rise in respiration,which is essential for the metabolic changes that occur during ripening.
Therefore,the correct option is $C$.

(B) Ethylene is a gaseous plant hormone that plays a crucial role in various physiological processes.
In pineapples,ethylene is widely used to initiate flowering and to synchronize fruit-set,which helps in harvesting the crop at the same time.
$ABA$ (Abscisic acid) is primarily a growth inhibitor.
Kinetin is a type of cytokinin that promotes cell division.
Gibberellins are primarily involved in stem elongation and seed germination.
Therefore,the correct option is $B$.

(B) The ripening of fruits like bananas is a metabolic process that is temperature-dependent.
Refrigeration slows down the enzymatic activities and the production of ethylene,which is the primary hormone responsible for fruit ripening.
By lowering the temperature,the rate of respiration and the ripening process are significantly reduced,thereby delaying the over-ripening of bananas.

(C) Ethylene is a gaseous plant hormone that plays a crucial role in the ripening of fruits.
It promotes the breakdown of chlorophyll,the synthesis of carotenoids and anthocyanins,and the conversion of starch into sugars,which makes the fruit soft and sweet.
In commercial agriculture,ethylene is widely used to artificially ripen climacteric fruits like bananas,mangoes,and tomatoes to ensure uniform ripening before they reach the market.

(C) Ethylene is a gaseous plant hormone known primarily for its role in fruit ripening. It promotes the ripening process by stimulating the breakdown of cell walls and the conversion of starches into sugars. It also accelerates senescence and abscission of plant organs like leaves and flowers.

(D) Ethylene $(C_2H_4)$ is a gaseous plant hormone that promotes fruit ripening. In commercial applications,a mixture containing $80\% C_2H_4$ and $20\% CO_2$ is often used to accelerate the ripening process of fruits like bananas and mangoes. The presence of $CO_2$ helps in controlling the rate of respiration during the ripening process.

(N/A) Ethylene is a simple gaseous plant growth regulator.
$1$. Discovery: It was discovered by $H.H. Cousins$ from ripened oranges.
$2$. Physiological Effects:
- It promotes horizontal growth of seedlings,swelling of the axis,and apical hook formation in dicot seedlings.
- It promotes senescence and abscission of plant organs,especially leaves and flowers.
- It is highly effective in fruit ripening. It enhances the respiration rate during ripening,known as respiratory climacteric.
- It breaks seed and bud dormancy and initiates germination in peanut seeds and sprouting of potato tubers.
- It promotes rapid internode/petiole elongation in deep-water rice plants.
- It promotes root growth and root hair formation,thus helping the plants to increase their absorption surface.

(N/A) In the context of plant physiology,the term 'volatile endocrine' refers to $Ethylene$ $(C_2H_4)$.
$Ethylene$ is a simple gaseous plant hormone (phytohormone).
It is categorized as a volatile substance because it exists in a gaseous state at physiological temperatures and can diffuse through the air to affect neighboring tissues or plants.
It acts as an endocrine-like signal because it is produced in one part of the plant and transported to other parts to regulate various physiological processes,such as fruit ripening,senescence,and abscission.

(N/A) Ethephon is an aqueous solution used as a source of ethylene. Its importance includes:
$1$. It is widely used to hasten fruit ripening in tomatoes and apples.
$2$. It accelerates the abscission in flowers and fruits (thinning of cotton,cherry,and walnut).
$3$. It promotes female flowers in cucumbers,thereby increasing the yield.
$4$. It is used to induce flowering in mangoes and pineapples.

(D) $(i)$ $2,4-D$ ($2,4-$dichlorophenoxyacetic acid) is a synthetic auxin that acts as a potent weedicide,specifically used to eliminate broad-leaved dicotyledonous weeds.
$(ii)$ Ethylene is a gaseous plant hormone primarily responsible for the ripening of fruits.

(C) Ethylene is a simple gaseous hydrocarbon and is a naturally occurring plant hormone.
It is primarily responsible for the ripening of fruits.
Treatment with ethylene gas or ethylene-releasing compounds accelerates the ripening process in climacteric fruits.

(C) Ethylene is a simple,gaseous hydrocarbon and is a naturally occurring plant hormone.
It plays a crucial role in fruit development and ripening.
It also controls the abscission of leaves and flowers.

(B) Abscission is the shedding of a body part. It refers to the process by which a plant intentionally drops one or more of its parts,such as a leaf,fruit,flower,or seed,due to changes in hormonal balance (specifically a decrease in auxin and an increase in ethylene).

(D) $Ethephon$ is an aqueous solution that is readily absorbed and transported within the plant and releases ethylene slowly.
$1$. It hastens fruit ripening in tomatoes and apples.
$2$. It accelerates abscission in flowers and fruits (thinning of cotton,cherry,walnut).
$3$. It promotes female flowers in cucumbers,thereby increasing the yield.
Therefore,all the given options are correct.

(C) Ethylene is a gaseous $PGR$ that acts as a plant growth inhibitor. While it can show some growth-promoting effects in specific contexts,it is primarily classified as a growth inhibitor because it promotes senescence and abscission of plant organs.

(C) The most widely used compound as a source of ethylene is $Ethephon$.
$Ethephon$ in an aqueous solution is readily absorbed and transported within the plant and releases ethylene slowly.
It is used to hasten fruit ripening in tomatoes and apples and accelerates abscission in flowers and fruits.

(A) Ethylene $(C_{2}H_{4})$ is a gaseous plant growth regulator that initiates flowering and synchronizes fruit set in pineapples.
It also induces flowering in mango trees.
Ethylene promotes root growth and root hair formation,thereby helping in increasing the absorption surface area.
Therefore,all three functions are attributed to Ethylene $(C_{2}H_{4})$.

(B) Climacteric fruits exhibit a sharp increase in their respiration rate during the ripening process.
During this ripening phase,the production of the plant hormone ethylene increases dramatically,often reaching up to $1000$ times the basal level.
Therefore,ethylene is directly associated with the phenomenon of climacteric ripening in fruits.

(D) The physiological effects of ethylene include:
$(i)$ Horizontal growth of seedlings.
$(ii)$ Swelling of the axis.
$(iii)$ Apical hook formation in dicot seedlings.
$(iv)$ Promotion of senescence and abscission of plant organs.
$(v)$ Breaking of seed and bud dormancy.
$(vi)$ Initiation of flowering in pineapple and mango.
Apical dominance is primarily caused by the hormone auxin,not ethylene.

(A) The triple response is a classic physiological effect observed in plants,primarily in pea seedlings,when exposed to ethylene gas.
This phenomenon was first described by the Russian physiologist Dimitry $N$. Neljubow.
The three components of the triple response are:
$(a)$ Inhibition of stem elongation.
$(b)$ Increased stem thickening (swelling).
$(c)$ Horizontal growth habit (diageotropism) of the stem.
Since $C_{2}H_{4}$ (ethylene) is the hormone responsible for these effects,the correct option is $A$.

(B) Ethylene is a gaseous plant hormone that has several physiological effects:
$1$. It promotes the formation of female flowers in cucumber ($I$ is an effect of ethylene).
$2$. $\alpha$-amylase production in barley grain is induced by Gibberellins $(GA)$,not ethylene ($II$ is incorrect).
$3$. It accelerates the ripening of fruits like tomato ($III$ is an effect of ethylene).
$4$. Sprouting in potato tubers is delayed by inhibitors like Maleic Hydrazide,not ethylene ($IV$ is incorrect).
Therefore,the effects of ethylene are $I$ and $III$.