Different Types of Stems with Example ppt

Ppt contains information about various types of Stems with its examples and some pictures.

1. Different Types of Stems with Example Jaipur National University School of Pharmaceutical Sciences Submitted To Madhvi Jain Associate Professor Submitted By Kartik Joshi Pharm D 2 nd Year

2. Content

3. What is Stems? Stems are one of the three organs of a plant. The primary function (most important job) of a stem is mechanical support. Mechanical support means the plant’s stem supports the plant and holds it upright to help it grow toward sunlight. Stems also connect the other organs of the plant.

4. Types of Stems There are several types of stems, including underground stems, subaerial stems, and aerial stems: Underground Stems :- Rhizome, Tuber, Corm, Bulb Subaerial Stems :- Runners, Stolons, Suckers, Offsets Aerial Stems :- Tendrils, Thorn, Bulbils, Cladode, Phylloclade

5. Underground Stems 1. Rhizome :- A rhizome is a modified underground stem of a plant that grows horizontally and produces roots and shoots. Rhizomes are also known as creeping rootstalks or rootstalks. Example:- Grass, Ginger, Snake Plant Functions of Rhizome Food storage : Rhizomes store starches and proteins. Asexual reproduction : Rhizomes allow plants to reproduce asexually. Perennation : Rhizomes help plants survive unfavorable seasons underground.

6. 2. Tuber :- These stems are swollen axillary branches of the stem that grow near the soil. Potatoes are example of tubers. Functions of Tubers Storage : Tubers store nutrients. Survival : Tubers help plants survive cold, dry, or adverse conditions. Reproduction : Tubers can reproduce asexually, with buds on the tuber growing into new plants. Food : Tubers are a rich source of carbohydrates and are eaten by humans.

7. 3. Corm :- A corm is a swollen, underground stem of a plant that stores food for the plant to survive harsh conditions. Corms are also known as bulbo -tubers or solid bulbs. Example :- Crocus, Oxalis, Elephant Garlic. Functions of Corm Store nutrients : Corms store starches and sucrose, which are used for growth and signaling. Survive harsh conditions : Corms help plants survive winter, drought, and heat. Reproduce : Corms produce offshoots called cormels , which can be separated from the parent corm and grown into new plants. Nourish daughter corms : While the daughter corm is developing, the parent corm provides nutrients. Degrade : When the daughter corm is mature enough to grow, the parent corm shrivels away.

8. 4. Bulb :- A bulb stem is a modified stem that grows underground and acts as a resting stage for some plants. The stem is covered in fleshy or membranous leaves that overlap and store food for the plant. Example:- Onion, Lilies Functions of Bulb Storage : The main function is to store carbohydrates and energy in the form of food reserves within the bulb’s fleshy scales (modified leaves). Dormancy : Bulbs allow plants to remain dormant during harsh conditions like cold winters and then sprout new growth when favorable conditions return. Vegetative reproduction : Some bulbs can also produce new plantlets or offsets from the base of the stem, enabling asexual reproduction.

9. Subaerial Stems 1. Runner :- A “ runner stem ” is a specialized plant stem that grows horizontally along the ground, producing roots and new plants at specific points called nodes. Example:- Spider plant, Trout lily, Purple Queen Key Points about runner stem Function : Primarily used for vegetative reproduction, not food storage. Growth pattern : Grows horizontally above the ground, rooting at nodes where new plants develop. Example plants : Strawberries are a well-known example of a plant that uses runners to spread.

10. 2. Stolon :- A stolon is a horizontal stem that grows on or just below the soil surface, and produces new plants. Example:- Strawberries Functions of Stolon Asexual reproduction : Stolons allow plants to reproduce without the need for another plant to mate with. Spread : Stolons help plants spread out and colonize new areas. Light seeking : Stolons help plants find light.

11. 3. Suckers :- Sucker is a modified sub-aerial stem. It is short, weak and slender and grows obliquely upward from the underground part of the stem. It bears small-scale leaves and produce roots at the nodal region. Example:- Pineapple, Banana, Red Raspberries, Forsynthia Function A sucker stem’s primary function is to enable vegetative propagation by producing new plants through shoots that grow from the base of the parent plant. Key points about Sucker stem Origin : They arise from the underground portion of the main stem, growing horizontally before emerging obliquely upwards to form new plants. Buds : Suckers have axillary buds at their nodes, which develop into new shoots and roots, forming a new individual. Propagation method : Gardeners often use suckers to propagate desired plant varieties by detaching them from the parent plant and transplanting them separately.

12. 4. Offsets :- An offset stem is a lateral branch of a plant that grows horizontally from the main stem. Offsets are a type of stem modification that helps plants reproduce through vegetative propagation. Example:- Pistia and Eichhornia Function Offsets help plants reproduce by spreading to new areas.
If an offset is separated from the parent plant, it can grow into a new plant. Characteristics Offsets are short and thick, like a runner.
Offsets have short internodes, which are the spaces between nodes.

13. Aerial Stems 1. Tendrils :- Stem tendrils are modified stems that help plants climb. They are slender, spirally coiled, and threadlike. Example:- Pumpkin, Watermelon, Passion Flower and Cucumber. Key points about tendril stems Climbing mechanism : Tendrils are modified stems that can coil around objects, enabling the plant to climb up vertical supports like trellises or other plants. Thigmotropism : They are sensitive to touch, meaning they will begin to coil when they contact a suitable surface. Light access : By climbing, the plant can position its leaves towards the sun, maximizing photosynthesis.

14. 2. Thorn :- A thorn stem is a modified stem of a plant that has a sharp point and protects the plant from herbivores. Thorns are hard, woody, and straight structures that grow from the axil of a leaf or the apex of a stem. Example:- Duranta, Bougainvillea, Climbing rose. Functions of thorn Defense : Thorns are a physical defense mechanism that deter herbivores from eating the plant. Water retention : Thorns may help plants retain water. Competition : Thorns may help plants compete with other plants for resources. Modification : Thorns are modified stems that grow in the axil of a leaf. Growth : Thorns grow for a limited time, which is called determinate growth.

15. 3. Bulbils :- A “bulbil stem” refers to a small, bulb-like structure that grows on the stem of a plant, acting as a form of asexual reproduction where the bulbil detaches from the parent plant and develops into a new, identical plant. Example:- Onion, Agave Function Bulbils are a method of vegetative propagation, meaning they allow a plant to reproduce without seeds by forming these small, plant-like structures on the stem. Location They typically develop in the leaf axils (where the leaf meets the stem) or sometimes in place of flowers.

16. 4. Cladode :- A cladode stem is a flattened, green stem that performs photosynthesis in place of leaves. Cladodes are also known as phylloclades or cladophylls. Example:- Asparagus Function of Cladode Photosynthesis : Cladodes are the main photosynthetic organs of a plant, allowing it to make its own food using sunlight. Asexual reproduction : Cladodes can reproduce asexually.

17. 5. Phylloclade :- A “phylloclade stem” is a modified, flattened stem of a plant that looks and functions like a leaf, essentially taking over the role of photosynthesis when the plant’s true leaves are reduced or absent. Phylloclades are found in xerophytes or land plants. Example:- Tapeworm Plant, Opuntia Function Photosynthesis : Phylloclades are green, leaf-like structures that contain photosynthetic pigments. They perform photosynthesis like leaves. Structural support : Phylloclades provide structural support to the plant. Survival : Phylloclades help plants survive in dry and arid environments. Food storage : Phylloclades store food.

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