CBSE Class 11 Biology Anatomy Of Flowering Plants Notes Set C

1. Study -f internal structure -f plants is called Anat-my. (Plant Anat-my)
2. Different -rgans in a plant sh-w differences in their internal structure due t- different functi-ns.
3. Within angi-sperms, the m-n-c-ts and dic-ts are als- seen t- be anat-mically different.
4. Internal structures als- sh-w adaptati-ns t- diverse envir-nments s- envir-nment influence the anat-my -f -rganism.
5. A tissue is a gr-up -f cells having a c-mm-n -rigin and usually perf-rming a c-mm-n functi-n.
6. -n the basis -f divisi-n capacity, plant tissue is -f tw- type.
- Meristematic tissue
- Permanent tissue.
7. Meristematic tissue:
- Cells -f meristematic tissue have divisi-n capacity.
- R--t tip and sh--t tip are the example -f apical meristem.
8. Axillary bud is the “left behind “part -f the sh--t tip. Such buds are present in the axils -f leaves and are capable -f f-rming a branch -r a fl-wer.
9. Intercalary meristem is the meristematic tissue present between permanent tissue and they are resp-nsible f-r primary gr-wth. They -ccur in grasses and regenerate parts rem-ved by the grazing herbiv-res.
10. B-th apical meristems and intercalary meristems are primary meristems because they appear early in life -f a plant and c-ntribute t- the f-rmati-n -f the primary plant b-dy.
11. Sec-ndary / lateral meristem/ cylindrical meristems: Fascicular vascular cambium,interfascicular cambium and c-rk-cambium are examples -f lateral meristems. These are resp-nsible f-r pr-ducing the sec-ndary tissues (increase in girth).
12. Permanent tissue:
- These are newly f-rmed cells fr-m meristematic tissue
- Structurally and functi-nally specialised.
- They d-n’t have divisi-n capacity.
- Permanent tissue is -f tw- types à Simple tissue and C-mplex tissue.
- Permanent tissues having all cells similar in structure and functi-n à simple tissues.
- Permanent tissues having many different types -f cells à C-mplex tissues.
- Simple tissue is -f three types:
- Parenchyma.
- C-llenchyma
- Sclerenchyma.

13. PARENCHYMA:
- F-rms the maj-r c-mp-nent within -rgan.
- Their walls are thin and made up -f cellul-se.
- The parenchyma perf-rms vari-us functi-ns like ph-t-synthesis, st-rage,secreti-n.

14. C-LLENCHYMA:
- It c-nsists -f cells which are much thickened at the c-rners due t- a dep-siti-n -f cellul-se, hemicellul-se and pectin.
- Intercellular spaces are absent.
- They pr-vide mechanical supp-rt t- the gr-wing parts -f the plant such as y-ung stem and peti-le -f a leaf.
- They make hyp-dermis in dic-ts.
- It is f-und either as a h-m-gene-us layer -r in patches.

15. SCLERENCHYMA:
- It c-nsists -f l-ng, narr-w cells with thick and lignified cell walls having a few -r numer-us pits.
- They are usually dead and with-ut pr-t-plasts.
- sclerenchyma tissue is tw- type fibres and sclereids.
- FIBRES are thick-walled, el-ngated and p-inted cells, generally -ccurring in gr-ups. 
- SCLEREIDS are spherical, -val -r cylindrical, highly thickened dead cells with very narr-w cavities (lumen). These are c-mm-nly f-und in the fruit walls -f nuts; pulp -f fruits like guava, pear and sap-ta; seed c-ats -f legumes and leaves -f tea.
- Sclerenchyma pr-vides mechanical supp-rt t- -rgans.

16. C-MPLEX TISSUE:
- Made -f m-re than -ne type -f cells and these w-rks t-gether as a unit.
- Xylem and phl-em are c-mplex tissue.

17. XYLEM:
- C-nduct mineral and water in upward directi-n
- Als- pr-vide mechanical supp-rt t- plant because -f lignified wall.
- It is c-mp-sed -f f-ur different kinds -f elements, namely,
§ tracheids,
§ vessels,
§ xylem fibres and
§ xylem parenchyma.
- Gymn-sperms lack vessels in their xylem.
- Tracheids are el-ngated -r tube-like cells with thick and lignified walls and tapering ends. These are dead and are with-ut pr-t-plasm.
- Vessel is a l-ng cylindrical tube-like structure made up -f many cells called vessel members.
- Each cells -f vessel are with lignified walls & a large central cavity and dead.
- Vessel members are interc-nnected thr-ugh perf-rati-ns in their c-mm-n walls.
- The presence -f vessels is a characteristic feature -f angi-sperms.
- Xylem fibres have highly thickened wall s- there is n- lumen.
- Xylem parenchyma cells are the -nly living cell in xylem and thin-walled, and their cell walls are made up -f cellul-se.
- The radial c-nducti-n -f water takes place by the ray parenchymat-us cells.
- Pr-t-xylem (early f-rmed xylem) & metaxylem (late f-rmed xylem) are tw- type -f primary xylem.
- Stem sh-ws ENDARCH arrangement -f xylem in which pr-t-xylem is t-wards centre and metaxylem is t-wards periphery.
- The r--t sh-ws EXARCH c-nditi-n where pr-t-xylem is t-wards periphery and meta xylem is l-cated t-wards centre.

18. PHL-EM:
- Phl-em transp-rts f--d materials, usually fr-m leaves t- -ther parts -f the plant.
- Phl-em in angi-sperms is c-mp-sed -f sieve tube elements, c-mpani-n cells(parenchymat-us), phl-em parenchyma and phl-em fibres.
- Gymn-sperms have albumin-us cells and sieve cells. But they lack sieve tubes and c-mpani-n cells.
- Sieve tube elements are als- l-ng, tube-like structures, arranged l-ngitudinally and are ass-ciated with the c-mpani-n cells.
- Their end walls are perf-rated in a sieve-like manner t- f-rm the sieve plates.
- A mature sieve element p-ssesses a peripheral cyt-plasm and a large vacu-le but lacks a nucleus.
- The functi-ns -f sieve tubes are c-ntr-lled by the nucleus -f c-mpani-n cells.
- The sieve tube elements and c-mpani-n cells are c-nnected by pit fields present between their c-mm-n l-ngitudinal walls.
- The c-mpani-n cells help in maintaining the pressure gradient in the sieve tubes.
- Phl-em parenchyma is made up -f el-ngated, tapering cylindrical cells, having cellul-sic cell wall and has plasm-deta c-nnecti-n thr-ugh pits.
- Phl-em parenchyma is absent in m-st -f the m-n-c-tyled-ns.
- Phl-em fibres (bast fibres) are made up -f sclerenchymat-us cells.
- These are generally absent in the primary phl-em but are f-und in the sec-ndary phl-em.
- Phl-em fibres -f jute, flax and hemp are used c-mmercially.
- The first f-rmed primary phl-em c-nsists -f narr-w sieve tubes and is referred t- as pr-t-phl-em and the later f-rmed phl-em has bigger sieve tubes and is referred t- as metaphl-em.

19. The Tissue System:
- THE EPIDERMAL TISSUE SYSTEM f-rms the -uter-m-st c-vering -f the wh-le plant b-dy and c-mprises epidermal cells, st-mata and the epidermal appendages – the trich-mes and hairs.
- It is the -uterm-st (usually single layer) layer -f the primary plant b-dy. It is made up -f parenchyma cells.
- Epidermis -f aerial parts -f plant has waxy dep-siti-n called cuticle t- prevent l-ss -f water.
- Cuticle is absent in r--t.
- St-ma(plural: st-mata) is the aperture, c-mp-sed -f tw- guard cells and present in epidermis f-r gase-us exchange and transpirati-n.
- In dic-t guard cells are bean shaped whereas in m-n-c-ts (grass) it is dumbbell shape.
- The -uter walls -f guard cells (away fr-m the st-matal p-re) are thin and the inner walls (t-wards the st-matal p-re) are highly thickened.
- The guard cells p-ssess chl-r-plasts and regulate the -pening and cl-sing -f st-mata.
- Subsidiary cells are specialized cells epidermis cells near the guard cell.
- The st-matal aperture, guard cells and the surr-unding subsidiary cells are t-gether called st-matal apparatus.
- The r--t hairs are unicellular el-ngati-ns -f the epidermal cells and help abs-rb water and minerals fr-m the s-il.
- The epidermal hairs -n stem are called trich-mes.
- Trich-mes are generally multicellular whereas r--t hair is unicellular.
- The trich-mes help in preventing water l-ss due t- transpirati-n.

20. THE GR-UND TISSUE SYSTEM
- All tissues except epidermis and vascular bundles c-nstitute the gr-und tissue.
- It c-nsists -f simple tissues such as parenchyma, c-llenchyma and sclerenchyma.
- Parenchymat-us cells are usually present in c-rtex, pericycle, pith and medullary rays, in the primary stems and r--ts.
- In leaves, the gr-und tissue c-nsists -f thin-walled chl-r-plast c-ntaining cells and is called MES-PHYLL.

21. THE VASCULAR TISSUE SYSTEM
- The vascular system c-nsists -f c-mplex tissues, the phl-em and the xylem and make vascular bundle.
- The vascular bundles f-rm the c-nducting tissue and transl-cate water, minerals and f--d material.
- -pen vascular bundle: In dic-tyled-n-us stems, cambium is present between phl-em and xylem.
- Cambium f-rms sec-ndary xylem and sec-ndary phl-em during sec-ndary gr-wth i.e. increase in girth.
- CL-SED VASCULAR BUNDLE: cambium is absent between xylem and phl-em in m-n-c-t stem.
- RADIAL VASCULAR BUNDLE: When xylem and phl-em within a vascular bundle are arranged in an alternate manner -n different radii. E.g. r--ts.
- C-NJ-INT TYPE: The xylem and phl-em are situated at the same radius -f vascular bundles’. e.g. leaves and stem.
- The c-nj-int vascular bundles usually have the phl-em l-cated -nly -n the -uter side -f xylem.

22. STELE à All tissues -n the inner side -f the end-dermis such as pericycle, vascular bundles and pith c-nstitute the stele.

23. M-N-C-TYLED-N-US R--T
- M-n-c-t r--t differ fr-m dic-t r--t in:
§ there are usually m-re than six (p-lyarch) xylem bundles in the m-n-c-t r--t. (in dic-t it is 2 -4 xylem bundle).
§ Pith is large and well devel-ped.
§ M-n-c-tyled-n-us r--ts d- n-t underg- any sec-ndary gr-wth.

24. DIC-TYLED-N-US STEM
- In typical y-ung dic-tyled-n-us stem sh-ws that the epidermis is the -uterm-st pr-tective layer -f the stem having cuticle, trich-mes and few st-mata.
- C-rtex is c-nsist -f three sub layers namely Hyp-dermis, C-rtex and End-dermis.
- Hyp-dermis: The -uter layer -f c-rtex, c-nsists -f a few layers -f c-llenchymat-us cells just bel-w the epidermis, which pr-vide mechanical strength t- the y-ung stem.
- C-rtical layers bel-w hyp-dermis c-nsist -f r-unded thin walled parenchymat-us cells with c-nspicu-us intercellular spaces.
- The innerm-st layer -f the c-rtex is called the END-DERMIS.
- The cells -f the end-dermis are rich in starch grains and the layer is als- referred t- as the STARCH SHEATH.
- PERICYCLE is made up -f sclerenchyma and present ab-ve the phl-em in semi-lunar patch and few celled thick.
- Medullary cells are radially placed parenchyma cells between vascular bundles.
- Each vascular bundle is c-nj-int, -pen, with endarch pr-t-xylem and arranged in ring.
- Pith -ccupy central place -f stem.

25. M-N-C-TYLED-N-US STEM
- The m-n-c-t stem has a sclerenchymat-us hyp-dermis, a large number -f scattered vascular bundles, each surr-unded by a sclerenchymat-us bundle sheath, and a large, c-nspicu-us parenchymat-us gr-und tissue.
- Vascular bundles are c-nj-int and cl-sed.
- Peripheral vascular bundles are smaller than the centrally l-cated -nes.
- The phl-em parenchyma is absent, and water-c-ntaining cavities are present within the vascular bundles.

26. D-RSIVENTRAL (DIC-TYLED-N-US) LEAF
- There are mainly three types -f tissue namely epidermis, mes-phyll and vascular bundle.
- Epidermis present b-th side upper(adaxial) and l-wer side (abaxial side).
- Abaxial surface has m-re st-mata than adaxial surface.
- Cuticle present b-th side.
- Mes-phyll present between upper & l-wer epidermis.
- Mes-phyll cells are basically parenchyma cell having chl-r-plast.
- They are differentiated in el-ngated PALISADE TISSUE and r-unded

SP-NGY PARENCHYMA.
- Palisade tissue are t-wards adaxial side and sp-ngy parenchyma is l-cated t-wards l-wer epidermis.
- Sp-ngy parenchyma has large air cavities and intercellular space.
- Vascular bundles are l-cated at midrib and veins.
- The size -f vascular bundle is depending up-n size -f vein.
- The vascular bundles are surr-unded by a layer -f bundle sheath cells.
- Dic-t leaf has reticulated venati-n.

27. IS-BILATERAL (M-N-C-TYLED-N-US) LEAF
- St-mata present -n b-th side -f leaf.
- Mes-phyll cells are n-t differentiated int- palisade and sp-ngy parenchyma.
- Bullif-rm cells are m-dified epidermal cells -n veins regulate the leaf surface exp-sure and curling in m-n-c-t leaf.
- Bullif-rm cells are larger than epidermal cells. When they are turgid the leaf surface is exp-sed, if they are flaccid the leaf curling -ccur.
- Because -f parallel venati-n, there is alm-st vascular bundles are similar in size except midrib.
- Mid rib vascular bundles are bigger in size.

28. SEC-NDARY GR-WTH
- Sec-ndary gr-wth is increase in girth/diameter.
- The tissues inv-lved in sec-ndary gr-wth are the tw- lateral meristems: VASCULAR CAMBIUM AND C-RK CAMBIUM.
- Vascular cambium is meristematic in nature and present between xylem and phl-em is called intrafasicular cambium.
- Interfasicular cambium is present between tw- intrafasicular cambium, it is sec-ndary in -rigin .
- Medullary cells present between vascular bundle bec-me meristematic and change int- interfasicular cambium.
- Intrafasicular and interfascicular cambium make a c-mplete ring which pr-duce sec-ndary phl-em t-ward periphery and sec-ndary xylem t-wards central side.
- The cambium is generally m-re active -n the inner side than -n the -uter.
S-, the am-unt -f sec-ndary xylem pr-duced is m-re than sec-ndary phl-em and f-rms a c-mpact mass.
- The primary and sec-ndary phl-em is crushed due t- c-ntinu-us f-rmati-n -f sec-ndary xylem.
- The primary xylem remains m-re -r less intact, in -r ar-und the centre.
- Sec-ndary medullary rays are pr-duced by cambium ring.
- They pass thr-ugh sec-ndary xylem and sec-ndary phl-em and resp-nsible f-r radial c-nducti-n -f mineral water and f--d.

29. SEC-NDARY GR-WTH IN R--TS
- In the dic-t r--t, the vascular cambium is c-mpletely sec-ndary in -rigin and -riginate fr-m pericycle.
- Pericycle l-cated just bel-w the primary phl-em and ab-ve the pr-t-xylem f-rming a c-mplete and c-ntinu-us wavy ring, which later bec-mes circular.
- After cambium ring f-rmati-n, the pattern -f sec-ndary gr-wth is same in dic-t r--t and dic-t stem.

30. SPRING W--D AND AUTUMN W--D
- The activity -f cambium is under the c-ntr-l -f many physi-l-gical and envir-nmental fact-rs.
- In the spring seas-n, cambium is very active and pr-duces a large number -f xylary elements having vessels with wider cavities. (due t- fav-urable seas-n).
- This w--d is lighter in c-l-ur and has a l-wer density is called spring w--d -r early w--d.
- In winter, the cambium is less active and f-rms fewer xylary elements that have narr-w vessels (less availability -f water) and this w--d is called autumn w--d -r late w--d. the autumn w--d is darker and has a higher density.
- The tw- kinds -f w--ds (spring +autumn) that appear as alternate c-ncentric rings, c-nstitute an annual ring. Annual rings seen in a cut stem give an estimate -f the age -f the tree.

31. HEART W--D:
- In -ld trees, the greater part -f (centrally l-cated) sec-ndary xylem is dark br-wn due t- dep-siti-n -f -rganic c-mp-unds like tannins, resins, -ils,
gums, ar-matic substances and essential -ils.
- These substances make it hard, durable and resistant t- the attacks -f micr--rganisms and insects. This regi-n c-mprises dead elements with highly lignified walls and is called heartw--d.
- The heartw--d d-es n-t c-nduct water but it gives mechanical supp-rt t- the stem.

32. SAP W--D:
- The peripheral regi-n -f the sec-ndary xylem, is lighter in c-l-ur and is kn-wn as the sapw--d.
- It is inv-lved in the c-nducti-n -f water and minerals fr-m r--t t- leaf. (physi-l-gical active)
- Heart w--d and sap w--d b-th c-ntain spring w--d as well as autumn w--d.

33. C-RK CAMBIUM
- C-rk cambium is lateral meristem and sec-ndary in -rigin.
- It is -riginated in c-rtical z-ne.
- C-rk cambium -r phell-gen is a c-uple -f layers thick. It is made -f narr-w, thin-walled and nearly rectangular cells.
- Phell-gen cuts -ff cells -n b-th sides.
- The -uter cells differentiate int- c-rk -r phellem while the inner cells differentiate int- sec-ndary c-rtex -r phell-derm.
- The c-rk is impervi-us t- water due t- suberin dep-siti-n in the cell wall. It perf-rms the functi-n -f epidermis i.e. pr-tecti-n as epidermis is destr-yed by activity -f cambium ring during sec-ndary gr-wth.
- The cells -f sec-ndary c-rtex are parenchymat-us.
- Phell-gen, phellem, and phell-derm are c-llectively kn-wn as PERIDERM.
- Due t- activity -f the c-rk cambium, pressure builds up -n the remaining layers peripheral t- phell-gen and ultimately these layers die and sl-ugh -ff.

34. BARK is a n-n-technical term that refers t- all tissues exteri-r t- the vascular cambium.
- Bark includes a number -f tissue types, viz., periderm and sec-ndary phl-em.
- Bark that is f-rmed early in the seas-n is called early -r s-ft bark.
- T-wards the end -f the seas-n, late -r hard bark is f-rmed.

35. LENTICELS:
- At certain regi-ns, the phell-gen cuts -ff cl-sely arranged parenchymat-us cells -n the -uter side instead -f c-rk cells.
- These parenchymat-us cells s--n rupture the epidermis, f-rming a lens shaped -pening called lenticels.
- Lenticels permit the exchange -f gases between the -uter atm-sphere and the internal tissue -f the stem. These -ccur in m-st w--dy trees