Lesson 10 of 10 · 13 min
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Next Toppers - 11th ScienceWhole chapter · Hinglish
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Must-know facts
20 facts
- 01Three tissue systems: epidermal, ground (fundamental), vascular (conducting).
- 02Cuticle is absent in roots.
- 03Guard cells: bean-shaped in most plants, dumb-bell shaped in grasses; inner wall thick, outer wall thin; they contain chloroplasts.
- 04Stomatal apparatus = pore + guard cells + subsidiary cells.
- 05Root hairs are unicellular; shoot trichomes are usually multicellular.
- 06Ground tissue = all tissue except epidermis and vascular bundles; in leaves it is the mesophyll.
- 07Open bundle has cambium (dicot stem); closed bundle has none (monocot).
- 08Radial bundles: roots. Conjoint bundles: stems and leaves, phloem usually outside the xylem.
- 09Dicot root example in NCERT: sunflower.
- 10Endodermis of root: barrel-shaped cells, no intercellular spaces, casparian strips of suberin on radial and tangential walls.
- 11Lateral roots and the vascular cambium arise from the pericycle.
- 12Dicot root: two to four xylem patches, small pith. Monocot root: usually more than six (polyarch), large pith, no secondary growth.
- 13Stele = pericycle + vascular bundles + pith (everything inside the endodermis).
- 14Dicot stem hypodermis: collenchyma. Monocot stem hypodermis: sclerenchyma.
- 15Starch sheath = endodermis of the dicot stem.
- 16Dicot stem pericycle: semi-lunar sclerenchyma patches above the phloem.
- 17Dicot stem bundles: ring, conjoint, open, endarch protoxylem.
- 18Monocot stem bundles: scattered, conjoint, closed, sclerenchymatous bundle sheath, no phloem parenchyma, water-containing cavities; peripheral ones smaller.
- 19Dorsiventral leaf: more stomata on the abaxial side; palisade adaxial, spongy abaxial.
- 20Isobilateral leaf: stomata on both sides; mesophyll undifferentiated; bulliform cells in grasses roll the leaf when flaccid.
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Key terms
20 terms
- Anatomy
- The study of the internal structure of an organism.
- Cuticle
- Waxy layer on the outside of the epidermis that limits water loss; missing in roots.
- Guard cells
- The pair of cells that enclose a stomatal pore and open or close it.
- Subsidiary cells
- Epidermal cells near the guard cells that have become different in shape and size.
- Stomatal apparatus
- The pore, its guard cells and the subsidiary cells taken together.
- Trichome
- A hair on the shoot epidermis, usually multicellular.
- Mesophyll
- The chloroplast-bearing ground tissue of a leaf.
- Open vascular bundle
- A bundle with cambium between xylem and phloem, able to make secondary tissue.
- Closed vascular bundle
- A bundle without cambium, so no secondary tissue forms.
- Radial bundle
- Xylem and phloem in separate patches on different radii, as in roots.
- Conjoint bundle
- Xylem and phloem together on the same radius, as in stems and leaves.
- Epiblema
- The outermost layer of the root, many of whose cells form root hairs.
- Casparian strips
- Bands of suberin on the radial and tangential walls of root endodermis cells.
- Pericycle
- Layer just inside the endodermis; origin of lateral roots and the vascular cambium.
- Conjunctive tissue
- Parenchyma lying between the xylem and phloem patches of a root.
- Stele
- All tissues inside the endodermis: pericycle, vascular bundles and pith.
- Polyarch
- Having many xylem bundles, usually more than six, as in the monocot root.
- Starch sheath
- The starch-rich endodermis of the dicot stem.
- Endarch
- Protoxylem towards the centre and metaxylem towards the outside of the bundle.
- Bulliform cells
- Large, empty, colourless adaxial epidermal cells of grass leaves that roll the leaf when flaccid.