1. What are the main parts of a plant?
The six basic parts into which a plant is primarily divided are the roots, stem, leaves, flowers, fruits, and seeds. All these parts fulfil certain functions and are essential in the growth, reproduction, and survival of a plant.
2. How do roots benefit a plant?
The roots help the plant in taking up water and nutrients from the ground, firmly anchoring the plant to the ground, and sometimes storing food and nutrients.
3. What is the function of the stem in a plant?
It supports the plant and holds the plant upright. Apart from this, it is involved in the transportation of water, nutrients, and sugars from roots to leaves. A storage site for nutrition is also provided.
4. Why are leaves important for a plant?
The leaves are essential to the photosynthetic function, which is the process by which plants take energy from the sun. In addition, they serve as the site for gas exchange and transpiration, the mechanisms of regulating the loss of water.
5. What are the different types of fruits?
Fruits can be of many different types. Types are as follows:
Simple Fruits: They are developed from one ovary. Example: cherry, tomato.
Aggregate Fruits: They develop from the ovaries of one flower. Examples: strawberry, raspberry.
Multiple Fruits: They develop from the ovaries of many flowers growing in a cluster. Example: pineapple.
6. What are the main parts of a flowering plant?
The main parts of a flowering plant are roots, stem, leaves, flowers, fruits, and seeds. Each part has specific functions that contribute to the plant's overall growth, survival, and reproduction.
7. How do roots help plants survive in different environments?
Roots help plants survive by anchoring them in the soil, absorbing water and nutrients, and storing food. They can adapt to different environments by growing deeper in dry conditions or developing specialized structures like prop roots in wet environments.
8. What is the difference between tap root and fibrous root systems?
A tap root system has a main central root with smaller lateral roots branching off, while a fibrous root system consists of many thin, branching roots of similar size. Tap roots are common in dicots and can grow deep, while fibrous roots are typical in monocots and spread widely near the soil surface.
9. How do stems support plant growth and survival?
Stems support plant growth and survival by providing structural support, conducting water and nutrients between roots and leaves, storing food, and producing new living tissue. They also help plants compete for sunlight by growing taller or spreading outward.
10. Why do some plants have aerial roots?
Some plants have aerial roots to absorb moisture and nutrients from the air, provide additional support, or help them climb. These roots are common in epiphytes (plants that grow on other plants) and some tropical species.
11. What is the function of vascular tissues in plant stems?
Vascular tissues in plant stems, namely xylem and phloem, function as the plant's transport system. Xylem conducts water and dissolved minerals upward from roots to leaves, while phloem distributes sugars and other organic compounds produced by photosynthesis throughout the plant.
12. How do leaves capture and use light energy?
Leaves capture light energy through chlorophyll pigments in their cells. This energy is used in photosynthesis to convert carbon dioxide and water into glucose and oxygen. The flat, broad shape of most leaves maximizes their surface area for light absorption.
13. Why do some plants have modified leaves?
Some plants have modified leaves to adapt to specific environmental conditions or functions. Examples include the spines of cacti for water conservation and defense, tendrils for climbing, and the insect-trapping structures of carnivorous plants.
14. What is the purpose of stomata in leaves?
Stomata are tiny pores in leaves that allow for gas exchange between the plant and the atmosphere. They open to allow carbon dioxide in for photosynthesis and release oxygen and water vapor, and close to prevent excessive water loss through transpiration.
15. What are the main parts of a typical flower?
The main parts of a typical flower are sepals (collectively called calyx), petals (collectively called corolla), stamens (male reproductive parts), and pistil (female reproductive part). These structures work together to facilitate plant reproduction.
16. What is the difference between simple and compound fruits?
Simple fruits develop from a single ovary of one flower, while compound fruits develop from multiple ovaries of one flower or from the ovaries of several flowers in an inflorescence. Examples of simple fruits include apples and peaches, while pineapples and figs are compound fruits.
17. How do plants respond to changes in light direction?
Plants respond to changes in light direction through phototropism. Stems typically exhibit positive phototropism, growing towards light sources, while roots show negative phototropism. This response helps plants optimize their light exposure for photosynthesis.
18. What is the function of nectar in flowers?
Nectar is a sugar-rich liquid produced by flowers to attract pollinators. It serves as a reward for animals that visit the flower, encouraging them to transfer pollen between flowers and facilitating plant reproduction.
19. How do plants respond to gravity?
Plants respond to gravity through gravitropism. Roots exhibit positive gravitropism, growing downward towards the center of the Earth, while shoots typically show negative gravitropism, growing upward against gravity. This response helps plants orient themselves for optimal growth and resource acquisition.
20. What is the role of plant hormones in growth and development?
Plant hormones, or phytohormones, play crucial roles in coordinating growth and development. They regulate processes such as cell division, elongation, fruit ripening, leaf abscission, and responses to environmental stimuli. Examples include auxins, cytokinins, gibberellins, abscisic acid, and ethylene.
21. How do deciduous trees prepare for winter?
Deciduous trees prepare for winter by stopping chlorophyll production, revealing other leaf pigments (creating fall colors), and forming an abscission layer at the base of leaf stems. This layer eventually causes leaves to fall off, reducing water loss and damage from freezing. The trees also store nutrients in their roots and enter a dormant state.
22. How do plants defend themselves against pathogens?
Plants defend themselves against pathogens through various mechanisms, including physical barriers (like waxy cuticles and bark), chemical defenses (such as antimicrobial compounds), and induced responses (like the production of defensive proteins). Some plants also have symbiotic relationships with microorganisms that help protect them.
23. What is the difference between determinate and indeterminate growth in plants?
Determinate growth occurs when a plant or plant part grows to a predetermined size and then stops, often seen in annual plants or fruits like tomatoes. Indeterminate growth is continuous throughout the plant's life, typical of perennial plants and some vegetative organs like roots.
24. How do plants communicate with each other?
Plants communicate with each other through chemical signals released into the air or soil. These signals can warn nearby plants of pest attacks, leading to increased defense responses. Some plants also communicate through underground fungal networks, sharing resources and information.
25. How do aquatic plants adapt to living in water?
Aquatic plants adapt to living in water through various modifications, such as aerenchyma tissue for buoyancy and gas exchange, floating leaves with stomata on the upper surface, reduced root systems, and flexible stems to withstand water currents. Some also have specialized structures for nutrient absorption directly from the water.
26. How do plants regulate their internal water pressure?
Plants regulate their internal water pressure through osmosis and the control of solute concentrations in their cells. They adjust the opening and closing of stomata, regulate ion uptake in roots, and produce osmolytes (soluble compounds) to maintain proper turgor pressure and water balance.
27. What is the function of resin in coniferous trees?
Resin in coniferous trees serves as a defense mechanism against insect attacks and fungal infections. When the tree is injured, resin flows to the wound, sealing it and trapping potential invaders. Some resins also have antimicrobial properties that further protect the tree.
28. How do plants adapt to high altitudes?
Plants adapt to high altitudes through various strategies, including developing a compact, low-growing form to avoid wind damage and conserve heat, increasing leaf thickness and hairiness to protect against intense UV radiation, and adjusting their metabolic processes to cope with lower oxygen levels and colder temperatures.
29. What is the role of mycorrhizae in plant nutrition?
Mycorrhizae are symbiotic associations between fungi and plant roots that enhance nutrient uptake for the plant. The fungi extend the reach of the root system, helping to absorb water and minerals (especially phosphorus) from the soil. In return, the plant provides carbohydrates to the fungi.
30. How do carnivorous plants digest their prey?
Carnivorous plants digest their prey using enzymes secreted by specialized glands in their traps. These enzymes break down the soft tissues of the captured insects, releasing nutrients that the plant can absorb. The process is similar to digestion in animals but occurs externally.
31. How do plants cope with salt stress?
Plants cope with salt stress through various mechanisms, including excluding salt at the roots, compartmentalizing salt in vacuoles, producing osmolytes to balance osmotic pressure, and shedding salt-laden leaves. Some halophytes (salt-tolerant plants) have specialized glands to excrete excess salt.
32. What is the purpose of latex in plants?
Latex in plants serves primarily as a defense mechanism against herbivores and pathogens. It can be toxic, sticky, or unpalatable, deterring animals from eating the plant. Latex also helps seal wounds in the plant, preventing water loss and entry of pathogens.
33. How do plants respond to touch?
Plants respond to touch through a process called thigmotropism or thigmonasty. This can involve rapid movements, like the closing of Venus flytrap leaves or the folding of Mimosa pudica leaves, or slower growth responses, such as trees growing stronger wood in areas exposed to wind. These responses help plants adapt to their physical environment.
34. What is the role of anthocyanins in plants?
Anthocyanins are pigments that give many flowers, fruits, and autumn leaves their red, purple, or blue colors. They serve multiple functions, including attracting pollinators and seed dispersers, protecting against excess light and cold temperatures, and acting as antioxidants to prevent cellular damage.
35. How do epiphytes obtain water and nutrients without soil?
Epiphytes obtain water and nutrients without soil through various adaptations. They absorb moisture and airborne nutrients through specialized structures on their leaves or roots. Many have water-storing tissues, and some form relationships with insects or other organisms that provide nutrients. They often have aerial roots that can absorb water from the air or collect debris for nutrition.
36. How do plants balance the need for carbon dioxide uptake with water conservation?
Plants balance carbon dioxide uptake with water conservation primarily through stomatal regulation. They open stomata to allow CO2 in for photosynthesis but close them to prevent excessive water loss. Many plants have adapted to open stomata during cooler periods (like night for CAM plants) or have developed specialized structures (like sunken stomata) to reduce water loss while maintaining gas exchange.
37. How do flowers contribute to plant reproduction?
Flowers contribute to plant reproduction by producing male and female reproductive cells (gametes). They attract pollinators, facilitate pollen transfer, and provide a protected environment for fertilization and seed development.
38. How do fruits develop from flowers?
Fruits develop from the ovary of a flower after fertilization. As the ovules develop into seeds, the ovary wall thickens and often becomes fleshy, forming the fruit. This process protects the developing seeds and often aids in seed dispersal.
39. How do seeds contribute to plant survival and dispersal?
Seeds contribute to plant survival by containing the embryo of a new plant along with stored food reserves. They aid in dispersal by having various adaptations (like wings, hooks, or edible flesh) that allow them to be carried by wind, water, or animals to new locations.
40. What is the function of cotyledons in seeds?
Cotyledons are seed leaves that store and provide nutrients to the developing embryo during germination. In some plants, they emerge above ground and perform photosynthesis until true leaves develop, while in others, they remain below ground.
41. How do plants transport water from roots to leaves?
Plants transport water from roots to leaves through xylem vessels using a combination of root pressure, capillary action, and transpiration pull. This process, known as the transpiration-cohesion-tension mechanism, allows water to move upward against gravity.
42. What is the role of phloem in plants?
Phloem is responsible for transporting sugars and other organic compounds produced by photosynthesis from leaves to other parts of the plant. This process, called translocation, ensures that all plant parts receive the nutrients they need for growth and metabolism.
43. What is the function of bark in woody plants?
Bark serves multiple functions in woody plants, including protection against physical damage, insect attacks, and extreme temperatures. It also helps prevent water loss and contains specialized cells for transporting nutrients. Some barks have additional functions like cork production or photosynthesis.
44. How do annual rings form in tree trunks?
Annual rings form in tree trunks due to seasonal changes in growth rate. During the growing season, trees produce larger, lighter-colored cells (early wood), while in the dormant season, they produce smaller, darker cells (late wood). These alternating layers create visible rings that can be used to determine a tree's age and past growing conditions.
45. What is the difference between monocot and dicot stems?
Monocot stems typically have scattered vascular bundles throughout the stem, while dicot stems have vascular bundles arranged in a ring. This difference affects their growth patterns, with monocots generally unable to produce secondary growth (increase in girth) unlike most dicots.
46. How do plants regulate water loss through leaves?
Plants regulate water loss through leaves primarily by controlling the opening and closing of stomata. They also use adaptations like waxy cuticles, reduced leaf size, or leaf hairs to minimize water loss. Some plants can change leaf orientation or curl their leaves to reduce exposure to intense sunlight and heat.
47. What is the function of root hairs?
Root hairs are thin extensions of root epidermal cells that greatly increase the surface area for water and nutrient absorption. They also help anchor the plant in soil and interact with soil microorganisms, facilitating nutrient exchange and symbiotic relationships.
48. How do plants store excess food?
Plants store excess food in various organs as carbohydrates, primarily starch. Common storage locations include roots (e.g., carrots), stems (e.g., potatoes), leaves (e.g., onion bulbs), and seeds. Some plants also store oils or proteins as energy reserves.
49. What is the purpose of thorns, prickles, and spines in plants?
Thorns, prickles, and spines are modified plant structures that serve primarily as defense mechanisms against herbivores. They can also help reduce water loss in arid environments and, in some cases, assist in climbing or support.
50. How do leaves adapt to different light conditions?
Leaves adapt to different light conditions through changes in size, thickness, and internal structure. Sun leaves are typically smaller, thicker, and have more compact cells, while shade leaves are larger, thinner, and have more spread-out cells to maximize light capture in low-light conditions.
51. What is the function of lenticels in woody stems?
Lenticels are small, raised pores in the bark of woody stems and roots that allow for gas exchange between the internal tissues and the atmosphere. They provide oxygen to the living cells in the bark and help release carbon dioxide and water vapor.
52. What is the role of trichomes on plant surfaces?
Trichomes are hair-like structures on plant surfaces that serve various functions, including reducing water loss, reflecting excess light, deterring herbivores, and secreting substances like oils or salts. In some plants, they also help with seed dispersal or water absorption.
53. What is the purpose of prop roots in plants like mangroves?
Prop roots in plants like mangroves serve multiple purposes. They provide additional support in unstable, waterlogged soils, help with gas exchange in oxygen-poor environments through specialized structures called pneumatophores, and assist in nutrient uptake from the water.
54. What is the function of tendrils in climbing plants?
Tendrils in climbing plants are modified stems, leaves, or parts of leaves that help the plant attach to and climb up surfaces. They can coil around supports, providing anchorage and allowing the plant to grow upwards towards light without investing energy in building strong, supportive stems.
55. What is the function of buttress roots in tropical trees?
Buttress roots in tropical trees are large, wide-spreading roots that extend from the trunk above the ground. They provide additional support and stability to tall trees growing in shallow, nutrient-poor soils. These roots also increase the surface area for nutrient absorption and help anchor the tree in areas prone to strong winds or flooding.
