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Anomalous secondary growth(Easy mind maps)

The document discusses anomalous secondary growth in various plant species, including Dracaena (monocot), Boerhaavia, Bougainvillea, Raphanus, and Beet (dicots). It explains the structural differences and growth patterns observed in stems and roots, highlighting how abnormal cambial activity leads to variations from typical secondary growth. Each species exhibits unique characteristics in their vascular tissue arrangement and cambial behavior, resulting in diverse morphological outcomes.

Science◦
ANOMALOUS SECONDARY GROWTH Saloni Rani Swain Botany Student President science college, Ahmedabad, Gujarat.
TOPIC Introduction Dracaena stem(Monocot) Bougainvillea and Boerhavia stem(Dicot) Raphanus and Beet (Root) 2
Introduction Anomalous or Abnormal secondary growth doesn’t follow normal secondary growth in which vascular cambium produces xylem on inside and phloem on outside.
ABNORMAL GROWTH 4 STEM ROOT Monocot Dicot Dracaena Boerhaavia Bougainvillea Raphanus Beet
DRACAENA (MONOCOT)
PRIMARY VASCULAR BUNDLE ❑ It is a monocot plant but due to abnormal growth of cambium it behave like a dicot. ❑ Roughly circular ❑ Epidermis is made up of single layered. ❑ Ground tissue – Parenchyamatous cell. ❑ Primary vascular bundle are collateral, conjoint, closed and endarch. ❑ They are scattered in parenchyma ground tissue. Each primary bundle is enclosed with thick-walled sclerenchymatous sheath.
SECONDARY GROWTH ❑ In old stem, epidermis replaced by formation of periderm (cork cambium – phellogen). ❑ Multilayered cortex. ❑ Old stem cambium develop outside the primary vascular bundle. ❑ Cambium ring form and it divide into two side outer and inner: if talk about outer side of cambium then found little parenchyma and conjunctive tissue is present inner side. ❑ Special type of stele present in dracaena such as Concentric Amphivasal vascular bundle( means secondary phloem inner side and secondary phloem outside )
MICROSCOPIC VIEW 8
BOERHAAVIA (DICOT)
PRIMARY GROWTH o Border- Nearly circular o Epidermis- Uniseriate, covered with cuticle, a few multicellular hair present. o Cortex- Outer 3-5 layer collenchyma(hypodermis) and inner layer is made up chlorenchyma cell. o Endodermis and Pericycle are not distinct. o Primary vascular bundle – Conjoint, collateral, Open, Endarch. 10
11 Three Vascular rings are form Outside from cambium there 15 to 20 small vascular bundles are present Middle ring – 6 to 14 , oval in shape. It help in secondary growth Inner ring – 2 to 3 larger vascular bundle (medullary ray) The protoxylem of these bundle face each other (help in secondary growth)
SECONDARY GROWTH Cambium 12 Secondary phloem – It present outer side ,thus it cut parenchymatous ground tissue. Secondary xylem- inner side and parenchymatous tissue (lignified) The activity of this cambium may stop and new cambium ring formed
❖ SUCCESSIVE CAMBIUM RING ARISE. PITH LARGER IN SIZE AND MADE UP OF PARENCHYMA CELL
MICROSCOPIC VIEW 14
BOUGAINVILLEA (DICOT)
PRIMARY GROWTH • It is similar to Boerhavia ,but minor difference can be seen like, inside the stele only two vascular bundles are form instead of three. • Epidermis- single layered (cuticle, thick, made up of parenchyma). • Hypodermis- Few layer thick (collenchyma). • Endodermis- Not distinct yet present. • Pericycle- Heterogenous arrangement of tissues (Parenchyma and sclerenchyma cell alter to each other). • Vascular bundle - Irregularly arrange. 16
SECONDARY GROWTH • Successive rings of Accessort cambia form. • Secondary growth - Formation of first cambial ring which is extra stelar in origin. • Cambium arise from pericycle. • First cambium life is too short • Secondary parenchyma- fusiform. 17 when new cambium form it break from interally and externally Internally- secondary xylem alternate to parenchyma Externally- secondary phloem above secondary xylem and parenchyma
• Thus successive concentric rings of vascular bundles are formed thick walled conjuctive tissue. • New cambium never make complete ring surrounding the pericycle it attach to above cambium • In some species phloem can not be distinguished. 18
MICROSCOPIC VIEW 19
RAPHANUS (ROOT) 20
RAPHANUS • It is a dicot root. • Primary xylem and phloem tissue arranged alternative. • Arrangement of protoxylem on outer side pr towards the cortex. It is called exarch. • During secondary growth the cells of pericycle convert in cambium. • The cells of upper portion of the xylem and cells of lower protion of phloem convert in cambium ring. • The first ring of cambium behave normal it produce less amount of secondary phloem on outer side and higher amount of secondary xylem inner side. • The parenchymatous cells of the secondary phloem produced remaining all cambium ring it is known as a accessory cambium. 21
➢ The all accessory cambium behave anomalous or abnormal function it produce less amount of secondary phloem on outer side and higher amount of secondary in inner side. ➢ Im secondary xylem the component of xylem parenchyma is higher it a anomalous of the root. ➢ The function of secondary xylem parenchyma is storage the food it is also a anomaly. ➢ Due to higher amount of secondary xylem parenchyma the Raphanus root look thick and fleshy. 22
RAPHANUS IN MICROSCOPE 23
BEET (ROOT) 24
BEET • It is a dicot root, thus storage zone is present. • Secondary growth in these storage root is anamalous. • Primary structure- Cotyledon type root with radical diarch. 25 Secondary Abnormal activity of cambium Abnormal position of cambium
• Secondary growth is initiated by the formation of a cambial ring. • Cambial ring formed pericycle outside protoxylem and parenchyma between the xylem and phloem. • Primary cambium--- Abnormal • Collateral, Conjoint. • Cambium after sometime ceases its activity. • Then second arise just outside the first parenchyma or outer ring of pericycle. • Second-- Abnormally behave like first. • Grow continiuosly parenchyma cell. • Dark red colour just because of Anthocyanin. 26 Inner side- sec. xylem and parenchyma alternative. Outer side- sec. xylem opposite to sec. xylem and parenchyma.
BEET ROOT MICROSCOPIC VIEW 27
REFERENCE • By S.N.PANDEY • https://images.app.goo.gl/T8DqP8i4n1hhoMBEA • https://images.app.goo.gl/ffE49jVmjeLj3uDLA • https://images.app.goo.gl/vw4X7z8zjnB6X2Bh7 • https://images.app.goo.gl/YwTJzYb2qvon5BbQ9 • https://images.app.goo.gl/ys7QYm1YYNG91ut2A • https://images.app.goo.gl/JKfyKaXRNUMLDMEv9 • https://images.app.goo.gl/sD1H3V4YQnLVVnK59 • https://images.app.goo.gl/XsiysexqJt4HLbbA6 • https://images.app.goo.gl/9GHC9EQNXMEKXMLW7 • https://images.app.goo.gl/3oeEwJr9QzCrz1ho6 • https://images.app.goo.gl/YWhKPxxd5K7jFZvn6 • https://images.app.goo.gl/BMfC5FmZXhh8bGvJA 28
THANK YOU Saloni Rani Swain saloniswain225@gmail.com