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ICAR JRF Plant Form and Physiology — practice questions — page 3

Explore 93 free Plant Form and Physiology questions in ICAR JRF Plant Sciences. Open each question or exercise to read its content, reference answers and available explanation.

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Plant Form and Physiology questions and exercises with answers

Showing questions 61–90 of 93.

Insect capturing leaves are thought to give carnivorous bog plants a supplementary source of what?Read the answer and worked solution →What are pneumatophores, found in some mangroves and cypress trees?Read the answer and worked solution →The air filled tissue in the root cortex of wild rice serves what purpose?Read the answer and worked solution →How do tropical epiphytes obtain the water and minerals they need?Read the answer and worked solution →Water potential is best defined as which quantity?Read the answer and worked solution →Water potential is expressed in which units, and what value is assigned to pure water?Read the answer and worked solution →Between two connected compartments, water moves in which direction?Read the answer and worked solution →Adding solutes to an aqueous system has what effect on its water potential?Read the answer and worked solution →Which component of water potential can a plant cell control metabolically?Read the answer and worked solution →What is the highest pressure potential quoted for a well watered plant?Read the answer and worked solution →A pressure potential of 1.5 MPa is equivalent to about how many pounds per square inch?Read the answer and worked solution →Matric potential arises from water binding to which kind of component?Read the answer and worked solution →What is the main driver of water movement in the xylem?Read the answer and worked solution →What is the consequence of cavitation in a tall tree?Read the answer and worked solution →What share of the water taken up by roots may be lost through transpiration?Read the answer and worked solution →How does the cuticle of a xerophyte compare with that of a mesophyte?Read the answer and worked solution →In phloem transport, which structures are correctly described as sinks?Read the answer and worked solution →How is sucrose loaded from mesophyll cells into the phloem sieve-tube elements?Read the answer and worked solution →Phloem sap is an aqueous solution containing up to what percentage of sugar?Read the answer and worked solution →How does the direction of flow in the xylem differ from that in the phloem?Read the answer and worked solution →The ability of a plant to use light to track time is called what?Read the answer and worked solution →Which statement about light absorption by the two forms of phytochrome is correct?Read the answer and worked solution →The chromophore of a phototropin is a covalently bound molecule of what?Read the answer and worked solution →Which blue light receptors set the 24 hour activity cycle of a plant?Read the answer and worked solution →Which organelles settle downward in gravity sensing cells and are also called statoliths?Read the answer and worked solution →Which is the only naturally occurring auxin that shows physiological activity?Read the answer and worked solution →The effect of cytokinins was first reported after adding what to plant embryos in culture?Read the answer and worked solution →Gibberellins are described as a group of about how many closely related hormones?Read the answer and worked solution →Low soil moisture raises the level of abscisic acid, which then does what?Read the answer and worked solution →In ripening fruit, ethylene stimulates which conversion?Read the answer and worked solution →

Worked practice questions

Insect capturing leaves are thought to give carnivorous bog plants a supplementary source of what?

  1. Potassium
  2. Nitrogen
  3. Phosphorus
  4. Magnesium
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Correct answer: B. Nitrogen

1. Carnivorous plants such as the Venus flytrap and the pitcher plant grow in bogs. 2. The soil of those bogs is low in nitrogen. 3. In these plants the leaves are modified to capture insects. 4. Those insect capturing leaves may have evolved to supply a supplementary source of much needed nitrogen. 5. Potassium, phosphorus and magnesium are all essential nutrients, but the bog shortage named here is nitrogen. 6. This is why the adaptation is nutritional rather than a defence against being eaten. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 30 "Plant Form and Physiology", section 30.4 Leaves_

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What are pneumatophores, found in some mangroves and cypress trees?

  1. Downward roots that store starch reserves
  2. Upward roots specialised for gas exchange
  3. Upward shoots that carry aerial flowers
  4. Downward shoots that anchor the trunk
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Correct answer: B. Upward roots specialised for gas exchange

1. Swamp soils are unstable and little oxygen reaches the submerged roots. 2. Some mangrove species and cypress trees answer this with pneumatophores. 3. Pneumatophores are upward growing roots containing pores and pockets of tissue specialised for gas exchange. 4. So they are roots, not shoots, and they grow up rather than down. 5. Starch storage roots such as carrots and beets are a different modification entirely. 6. Wild rice solves the same oxygen problem differently, with large air spaces called aerenchyma in the root cortex. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 30 "Plant Form and Physiology", section 30.4 Leaves_

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The air filled tissue in the root cortex of wild rice serves what purpose?

  1. It provides a path for oxygen to reach root tips
  2. It provides a store of sugars for the root tips
  3. It provides buoyancy that lifts the leaves clear
  4. It provides a barrier that excludes soil bacteria
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Correct answer: A. It provides a path for oxygen to reach root tips

1. Wild rice is an aquatic plant with large air spaces in the root cortex. 2. That air filled tissue is called aerenchyma. 3. It provides a path for oxygen to diffuse down to the root tips. 4. Those root tips are embedded in oxygen poor bottom sediments, which is why the path is needed. 5. Buoyancy of leaves is a separate adaptation of aquatic plants whose intercellular spaces help the leaf float. 6. Sugar storage and bacterial exclusion are not the roles given to this tissue. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 30 "Plant Form and Physiology", section 30.4 Leaves_

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More Plant Sciences topics

Plant ReproductionSoil and Plant Nutrition