Plants Vegetative Structures

• The root system anchors the plant to the ground and absorbs water and minerals from the soil.
• Xylem and phloem together form a stele.
• Protostele is a type of stele where there is no pith and phloem surrounds the core of xylem.
• Haplostele is a type of stele where the xylem mass is circular.
• Actinostele is a type of stele where the xylem is star-shaped.
• Plectostele is a type of stele where the xylem mass is a series of plates.
• Siphonostele is a type of stele where phloem surrounds one core of xylem with a pith and occurs in the shoot of ferns, seed plants, and roots of monocots.
• Amphiphloic is a type of stele where xylem is surrounded by phloem externally and internally.
• In ferns, the leaf trace departs, the leaf gap is not close, and the leaf trace and gap are close.
• In other cryptogams, the leaf traces and gaps are close, and in cross-section, the stele appears as a series of bundles.
• Ectophloic is a type of stele where phloem surrounds the xylem only externally and is found in phanerogams.
• Atactostele is a type of stele where the stele of a monocot is separated bundles everywhere.
• Polyciclic stele is a type of stele with two or more concentric vascular cylinders and is found in some roots and shoots.
• Exarch protostele is a type of stele found in roots where the protoxylem is outwards.
• Conducted elements pass from veinlet to mesophyll through bundle sheath.
• Leaf development involves the differentiation of the apical meristem which results in an enlargement, a slight bulge, an enlargement, a leaf primordium, and the formation of a leaf.
• Veinlets are surrounded by bundle sheath and have an unbroken connection with vascular elements of stem, petiole, and midrib.
• These plants have an enlarged bundle sheath with mesophylls of few or no grana in their chloroplasts.
• Large veins contain tracheids, sieve tubes, companion cells, and supportive cells.
• Small veins contain few vascular elements with few or no supportive cells.
• The vascular system consists of a midrib and branched veins which conduct water, salt, and food and support the mesophyll.
• Vascular bundles are embedded in parenchyma and fibers are associated with vascular bundles with some collenchyma under the epidermis.
• The petiole consists of xylem on the upper side and phloem on the lower one.
• During the early stage of development, procambium, which is located beneath the primordium, transforms into vascular tissues.
• Phyllotaxy, or the distribution of leaves, can occur in four patterns: opposite, alternate, whorled, and spiral.
• Spongy parenchyma is found above the veins and consists of irregular, loosely arranged cells that extend from the palisade parenchyma to the lower epidermis.
• Substomatal chambers are air spaces beneath the guard cells and are located within spongy parenchyma to allow and facilitate the gaseous exchange.
• The older leaf primordium determines the position of the next primordium.
• Some plants, such as corn, undergo C4 photosynthesis.
• Xylem is located towards the upper surface and phloem towards the inner surface.
• Endarch protostele is a type of stele found in shoots where the protoxylem is inwards.
• Transition zone is the interface between the roots and the shoots.
• Rhyniophytes are early vascular plants that include Cooksonia and Rhynia.
• Zosterophyllum is a type of plant that belongs to the Zosterophyllotes division.
• Living cells’ activity ensure the movement of water & minerals through dead cells.
• Eusporangium is the typical type of sporangium in vascular plants.
• Sporophytes of vascular plants possess a well-developed vascular system to conduct water, minerals, and food.
• Some trees have no annual rings due to conditions that aren't uniform, resulting in early vessels being larger than late vessels and creating a porous wood.
• Stem cells store food & water.
• Bark is all tissues outside the vascular cambium.