METHODS TO STUDY THE MINERAL REQUIREMENTS OF PLANTS Questions in English

(D) Hydroponics is the technique of growing plants in a nutrient solution without soil.
This method involves the use of an aqueous solution containing all essential mineral elements in the correct proportions to support plant growth.
Therefore,it is defined as the cultivation of plants in an aqueous balanced nutrient solution.

(C) The mineral content of a plant is determined through a process called $Ash \ analysis$.
In this method,plant tissue is dried to remove water,and then it is burned at a high temperature.
The organic matter is oxidized and released as gases,leaving behind the inorganic mineral elements in the form of $Ash$.
This $Ash$ is then analyzed to identify and quantify the mineral elements present in the plant.

(C) Hydroponics is a technique of growing plants in a nutrient solution (liquid culture medium) without soil. This method allows for the precise control of nutrient availability and is used to identify essential elements required for plant growth.

(D) The correct answer is $D$.
Julius von Sachs $(1860)$ demonstrated for the first time that plants could be grown to maturity in a defined nutrient solution in complete absence of soil.
However,the specific nutrient culture solution composition commonly used in hydroponic studies was proposed by Knop $(1865)$ and later refined by Arnon and Hoagland $(1940)$.

(D) The charcoal culture experiment is considered superior to the water culture (hydroponics) experiment for several reasons:
$1$. Support: Charcoal provides a solid medium that offers physical support to the plant roots,which is often lacking in simple water culture setups.
$2$. Aeration: Charcoal is porous,which facilitates better gas exchange and prevents the roots from suffocating due to lack of oxygen,thereby solving the problem of aeration.
$3$. Inert nature: Charcoal is chemically inert,meaning it does not react with the nutrient solution,ensuring that the mineral availability remains controlled and consistent.

(B) Hydroponics is a method of growing plants in a nutrient-rich water solution instead of soil.
This technique allows for the precise control of nutrient availability,$pH$,and aeration for the plant roots.
It is widely used in research and commercial agriculture to study plant mineral requirements.

(A) Hydroponics is a technique of growing plants in a nutrient solution in the absence of soil.
It is also known as soilless culture.
In this method,plants are grown in a defined nutrient solution,which provides all the essential minerals required for plant growth.
Therefore,the correct option is $A$.

(A) Sand culture is a method of growing plants in an inert medium like sand,which is supplied with a nutrient solution.
Since the plants are grown without soil,this technique is commonly referred to as soilless cultivation.
This method provides the roots with a natural environment and ensures proper aeration,which is beneficial for plant growth.

(D) Hydroponics is a technique of growing plants in a nutrient solution.
This method involves growing plants in a defined nutrient solution rather than soil.
This solution contains essential mineral nutrients required for the growth and development of the plant.
Therefore,a hydroponic solution is a nutrient-rich solution used for soil-less cultivation.

(D) Hydroponics is a technique of growing plants in a nutrient solution.
It has been successfully employed as a technique for the commercial production of vegetables such as tomato,seedless cucumber,and lettuce.
This method allows for controlled growth conditions,efficient use of water and nutrients,and higher yields in a smaller space.

(B) Hydroponics is a technique of growing plants in a nutrient solution.
It is primarily used to identify essential elements required by plants and their deficiency symptoms.
Advantages of hydroponics include:
$1$. It allows for the control of nutrient supply.
$2$. It protects plants from soil-borne pathogens and infections.
$3$. It is highly efficient in terms of water usage.
However,hydroponics is not a method used for the removal of weeds,as weeds are unwanted plants that grow in soil-based agriculture. Therefore,option $B$ is the correct answer.

(D) The given experimental set-up represents the technique of hydroponics or nutrient solution culture.
In this method,plants are grown in a defined nutrient solution.
This setup includes a tube for adding water and nutrients,and an aerating tube to provide oxygen to the roots,which is essential for proper plant growth and mineral uptake.
Therefore,it is used to study the mineral requirements of plants.

(D) Hydroponics is a technique of growing plants in a nutrient solution instead of soil.
This method was first demonstrated by Julius von Sachs in $1860$.
In this technique,plants are grown in a container with a defined nutrient solution that provides all the essential minerals required for the plant's growth and development.
This method is widely used for the commercial production of vegetables like tomatoes,seedless cucumbers,and lettuce.

(C) Cultivation of plants by placing the roots in a nutrient solution without any soil is called hydroponics.
It is also known as soilless culture,water culture,or solution culture.
This technique is used to determine which mineral elements are essential for plant growth and to observe the symptoms produced by the absence or deficiency of these essential elements.

(N/A) Hydroponics is the technique of growing plants in a nutrient solution in the absence of soil.
Since the plant roots are exposed to a limited volume of the solution,any impurities in the water or nutrient salts can lead to toxicity or nutrient imbalance.
Furthermore,to ensure that only the specific minerals being studied are affecting the plant's growth,it is essential to use highly purified water and nutrient salts.
This prevents contamination and ensures that the observed physiological responses are solely due to the experimental variables,thereby maintaining optimum plant growth.

(N/A) $\Rightarrow$ Julius von Sachs,a prominent German botanist,demonstrated for the first time that plants could be grown to maturity in a defined nutrient solution.
$\Rightarrow$ The technique of growing plants in a nutrient solution is known as hydroponics.
$\Rightarrow$ Since then,a number of improvised methods have been employed to try and determine the mineral nutrients essential for plants.
$\Rightarrow$ The essence of all these methods involves the culture of plants in a soil-free,defined mineral solution.
$\Rightarrow$ These methods require purified water and mineral nutrient salts.
$\Rightarrow$ After a series of experiments in which the roots of the plants were immersed in nutrient solutions and wherein an element was added/removed or given in varied concentrations,a mineral solution suitable for plant growth was obtained.
$\Rightarrow$ By this method,essential elements were identified and their deficiency symptoms were discovered.
$\Rightarrow$ Hydroponics has been successfully employed as a technique for the commercial production of vegetables such as tomato,seedless cucumber,and lettuce.
$\Rightarrow$ It must be emphasized that the nutrient solutions must be adequately aerated to obtain optimum growth.

(N/A)

Soil Culture	Hydroponics
$(1)$ The method of growing plants in soil.	$(1)$ The technique of growing plants in a nutrient-rich solution.
$(2)$ Soil acts as a complex reservoir of minerals,making it difficult to maintain a precise nutrient balance.	$(2)$ Nutrient solutions are prepared artificially,allowing for precise control and maintenance of nutrient balance.
$(3)$ There is a high risk of soil-borne pathogens and diseases.	$(3)$ It provides protection against soil-borne pathogens and diseases.
$(4)$ There is a high possibility of weed growth alongside the crop.	$(4)$ It offers significant relief from weed growth.
$(5)$ It is difficult to study the specific deficiency symptoms of individual mineral elements.	$(5)$ It is highly effective for studying the deficiency symptoms of specific mineral elements.

(N/A) The technique shown is Hydroponics,which was first demonstrated by Julius Von Sachs in $1860$.
$(b)$ Three plants for which this technique can be employed for commercial production are:
$(i)$ Solanum lycopersicum (Tomato)
$(ii)$ Hibiscus esculentus (Okra)
$(iii)$ Solanum melongena (Brinjal)
$(c)$ The significance of the components is as follows:
- Aerating tube: It provides air (oxygen) to the nutrient solution,which is essential for the respiration and optimum growth of roots.
- Feeding funnel: It is used to add water and nutrient salts to the solution as per the requirement of the plant.

(D) Hydroponics is not widely adopted for commercial crop production due to several reasons:
$(1)$ Economic factors: The initial setup cost and ongoing maintenance of hydroponic systems are significantly higher compared to traditional soil-based farming.
$(2)$ Disease management: In hydroponic systems,water-borne pathogens can spread rapidly throughout the entire crop,leading to significant losses.
$(3)$ Knowledge gap: Many farmers lack the specialized technical knowledge required to manage nutrient solutions and environmental parameters effectively.
$(4)$ Environmental sensitivity: Plants grown hydroponically can be less resilient to extreme environmental fluctuations. In hot seasons or conditions with low $O_2$ availability,both the yield and quality of the produce may decrease significantly.

(A) In hydroponics,specifically in systems designed for flowering cultures,the nutrient solution is not discarded. Instead,it is constantly recycled using a pump to ensure that the plants receive a continuous supply of essential minerals and oxygenated water.

(B) In $1860$,Julius von Sachs,a prominent German botanist,demonstrated for the first time that plants could be grown to maturity in a defined nutrient solution in the complete absence of soil.

(A) The practice of growing plants in a nutrient-enriched water solution without soil is known as hydroponics.
The system of growing plants where the roots are suspended in the air and sprayed with a nutrient-rich mist is known as aeroponics.

(A) Aeroponics is a method of growing plants in an air or mist environment without the use of soil or an aggregate medium.
Like hydroponics,it relies on providing nutrients directly to the roots,but instead of a liquid nutrient solution,it uses a fine mist,making it a closely related technique based on the same principle of soil-less cultivation.

(C) Hydroponics is the technique of growing plants in a nutrient solution without soil. In this method,plants are raised in tanks filled with a water solution containing appropriate quantities of all essential mineral elements. This technique is widely used for the commercial production of vegetables like tomatoes,seedless cucumbers,and lettuce,as well as for flower culture.

(B) Hydroponics is a technique of growing plants in a nutrient solution.
This method involves growing plants in a defined nutrient solution in the absence of soil.
This technique is widely used to identify the essential mineral elements required for plant growth and to study their deficiency symptoms.

(C) The major disadvantages of hydroponics are as follows:
$(i)$ It requires a high initial investment for setting up the infrastructure,such as nutrient delivery systems,lighting,and climate control.
$(ii)$ It demands specialized technical knowledge and constant monitoring of nutrient solutions,$pH$ levels,and environmental conditions to ensure plant health.
Therefore,both $(A)$ and $(B)$ are correct.

(D) Hydroponics is a technique of growing plants in a nutrient solution.
It is a useful technique for identifying essential mineral elements required by plants.
By using this method,researchers can control the nutrient supply to the plants,which allows them to identify specific essential elements and observe their deficiency symptoms.

(D) Soilless culture,also known as hydroponics,allows researchers to control the exact nutrient composition of the growth medium.
By systematically removing or adding specific minerals,scientists can determine the essentiality of an element for plant growth.
Furthermore,by varying the concentration of these elements,it is possible to observe and document the specific deficiency symptoms caused by the lack of an element and the toxicity symptoms caused by an excess of an element.
Therefore,all of the above options are correct.

(C) In hydroponics,iron is often added in the form of a chelate,specifically ferric $EDTA$ (Ethylenediaminetetraacetic acid).
This is because iron is prone to precipitation in nutrient solutions,especially at higher $pH$ levels.
$EDTA$ acts as a chelating agent that keeps the iron in a soluble form,making it readily available for plant uptake.

(D) Hydroponics is the technique of growing plants in a nutrient solution. This method is used to determine the mineral nutrients essential for plants.
Statement $I$ is correct as it is the primary purpose of this technique.
Statement $II$ is incorrect because hydroponics involves the culture of plants in a soil-free,defined mineral solution,not in soil.
Statement $III$ is incorrect because it requires purified water and defined (not non-defined) mineral nutrient salts.
Statement $IV$ is incorrect because plants are grown in a soil-free medium,not sandy soil.
Statement $V$ is correct as this method helps in identifying essential elements and their deficiency symptoms.
Therefore,statements $II, III,$ and $IV$ are incorrect.

(C) Hydroponics is classified into three main types: tank system,film system,and aeroponics.
In the tank system,roots are submerged in a nutrient solution,and air is bubbled through the solution to provide oxygen.
In the film system,plants are grown in a tube containing a thin film of recirculated nutrient solution.
In aeroponics,roots are suspended in the air over the nutrient solution,which is converted into a nutrient mist by a rotor.

(C) Hydroponics is a technique of growing plants in a nutrient solution rather than in soil. In this method,the roots of the plants are immersed in a solution containing essential mineral nutrients,which allows for the study of plant growth and mineral requirements under controlled conditions.

(D) Hydroponics is the technique of growing plants in a nutrient solution.
To ensure successful growth,the nutrient solution must be aerated to provide oxygen to the roots.
Furthermore,it is essential to prevent light from reaching the roots to inhibit the growth of algae,which would otherwise compete with the plants for nutrients and oxygen.
Therefore,the containers are often covered or painted to block light.

(A) In hydroponics or nutrient solution culture,the roots of plants are submerged in a nutrient solution.
For the roots to remain healthy and perform their metabolic activities,such as the uptake of minerals and water,they require a continuous supply of oxygen for respiration.
If the solution is not aerated,the roots may suffer from oxygen deficiency,leading to stunted growth or root decay.
Therefore,a bent tube is provided in the jar to facilitate the aeration of the nutrient solution.
Thus,both the Assertion and the Reason are correct,and the Reason provides the correct explanation for the Assertion.

(A) The term '$Hydroponics$' is derived from two Greek words: '$Hydro$' meaning '$water$' and '$ponos$' meaning '$labor$'.
It is a technique of growing plants in a nutrient-rich solution without the use of soil.
This method is also known as soil-less culture or solution culture.
Therefore, the correct option is $A$.

(D) In $1860$,the prominent German botanist Julius von Sachs demonstrated for the first time that plants could be grown to maturity in a defined nutrient solution in the complete absence of soil. This technique of growing plants in a nutrient solution is known as hydroponics.

(D) Hydroponics is a method of growing plants in a nutrient-rich aqueous solution without the use of soil.
This technique allows for the controlled supply of essential minerals directly to the plant roots.
Since both options $A$ (growing plants in a nutrient solution) and $C$ (growing plants without soil) describe the definition of hydroponics,the correct answer is $D$.

(A) The figure shows a plant growing in a nutrient solution with an aeration tube,which is the standard experimental setup for $Hydroponics$.
$Hydroponics$ is the technique of growing plants in a nutrient solution.
This method requires purified water with mineral nutrient salts.
Therefore,the correct option is $A$.

(D) Hydroponics is a technique of growing plants in a nutrient solution.
Its uses include:
$1$. Commercial production of vegetables like tomatoes,seedless cucumbers,and lettuce.
$2$. It allows for the identification of essential elements and their deficiency symptoms by omitting specific minerals from the solution.
$3$. It helps in studying the effects of mineral toxicity on plant growth.
Therefore,all the given options are correct uses of hydroponics.

(C) Hydroponics is the technique of growing plants in a nutrient-rich solution instead of soil. This method allows for the cultivation of plants in controlled environments,such as terraces or balconies,by providing essential minerals directly to the roots through water.