Each develops into a separate embryo independently. Leaves consist usually of three different tissues: the mesophyll, the epidermis and the vascular tissues. One male nucleus fuses with the oosphere to form oospore. Each ovule (megasporangium) has a mass of nucellar tissue. Pollination takes place at this stage. These branches also bear foliage leaves. A spur (Fig. The Questions and A) ... the terminal portion of microsporophyll of male cone is called . Intine grows out to form the pollen tube. The first appear after the seed germinates and are called cotyledons or "seed leaves." Question bank for NEET. It bears a nua Der of spirally arranged microsporophylls or stamens. The hypocotyl elongates to form a loop. Plant develops both male and female strobili on the same plant. The pollen tube grows through the nucellus. 15. They mostly grow in high altitudes (ranging from 1,200 to 3,000 metres). Answers of The mesophyll tissue of Pinus needle is -a)Collenchymab)Armed parenchymac)Spongy parenchymad)Transfusion tissueCorrect answer is option 'C'. It produces characteristic scaly bark. The upper four nuclei are separated by incomplete cell walls. Some part of the ovuliferous scale fuses with the developing seed. Some are thin membranous and are directly attached to the central axis. Roots may be covered by lycorrhizal fungus. Exine of the pollen grain ruptures. It is present in the form of strips. A gap is produced between the ends of the ovuliferous scales. The ground tissue system, the mesophyll, is divided into two regions: the palisade parenchyma, located beneath the upper epidermis and composed of columnar cells oriented perpendicular to the leaf surface, and spongy parenchyma, located in the lower part of the leaf and composed of irregularly shaped cells. It is a true assimilation tissue. | EduRev NEET Question is disucussed on EduRev Study Group by 142 NEET Students. It is covered with a scaly bark. Cell walls are thickened due to deposition of pectin. The dissolved tissue becomes mucilagenous and project out through the micropyle in the form of a droplet and is called pollination drop. These are covered by one or two scale leaves. Family –Pinaceae . When you hear about plants, everything seems to end in the suffix 'phyll.' The cells adjacent to the xylem are called tracheidal cells. The strobili are monosporous. It crushes all nueellar tissue except a small amount near the micropylar end. There is no vegetative reproduction in Pinus. They bear only scale leaves. Can you explain this answer? The remaining large cell is known as the tube cell. These are called scalariform tracheids. A fully developed embryo is in the form a short straight axis. Those parts of the bundle which have still been differentiated into conductive tissue cannot undergo further cell divisions. 1 Fnidermis: The surface is covered by an epidermis. This radicle grows down into the soil and forms the primary root. This tissue is called the mesophyll, meaning "middle leaf," and comes in two flavors: the palisade mesophyll (sometimes called palisade parenchyma) and the spongy mesophyll. Pinus is a tall tree, looks conical in appearance and forms dense evergreen forest in the North temperate and sub-alpine regions of the world. It has branches confined to the apical region. You can study other questions, MCQs, videos and tests for NEET on EduRev and even discuss your questions like It produces gaps in ovuliferous scales. These are small soft needle-shaped leaves and their number varies from 3 or more (P. contorta, banksiana and sylvestris) to eighteen … Spongy tissue is a type of tissue found both in plants and animals.. In plants, a group of cells located in the meristem (meristematic tissue) act as stem cells found in animals. The production of female cones is initiated in the winter. 28) is called unifoliar if only one leaf is present at the apex of the dwarf shoot, bifoliar if two leaves are present, trifoliar if three leaves are present, and so on. side. Endodermis and vascular tissues: Endodermis is present outside the pericycle. It also cut off generative cell adjacent to the prothalial cells. It passes through the neck of the archegonium and touches the oosphere. the repeated divisions. Each male cone has a central axis. In grasses with the C 3 pathway the vascular tissue is surrounded by two bundle sheaths. It splits the testa at the micropylar end. It is of two types primary transfusion tissue present next to the midrib bundle and secondary transfusion tissue that runs upto margins of the leaf. Top left and top centre: showing internal resin traversing the scale leaf, notice the spiral wall-thickenings in the xylem tracheids crossing the middle of the picture at top right. Can you explain this answer? A single layered thin walled endodermis is present outside the pericycle. Apart from being the largest NEET community, EduRev has the largest solved Some species of this genus include, Pinus roxburghii, P. wallichiana, P. gerardiana and P. insularis. Genus - Pinus . The antheridial cell cut off second prothalial cell. They are produced in clusters near the tip of the long shoots. Which of the following tissue is present in the leaves of Pinus and serve to conduct water and food [CPMT 1999, 2001] A) Its cells adjacent to the phloem are called aluminous cells. There is a small ventral canal cell below the neck. They are surrounded by a single integument. In Pinus it consists of tracheids and albuminous cells. The unutilized prothalial tissue forms the endosperm. …a central tissue, called the mesophyll, surrounded on either side by upper and lower epidermis. Four species of pinus are found in Pakistan: Pinus wallichiana; Pinus halepensis; Pinus roxburghil; Pinus gerardiana. It has world wide in distribution. A number of hypodermal cells act sporangial initials. Most of the interior of the leaf between the upper and lower layers of epidermis is a parenchyma (ground tissue) or chlorenchyma tissue called the mesophyll (Greek for "middle leaf"). In vascular plants, the mesophyll layer, being a ground tissue, is the product of a group of cells known as ground meristematic cells which are themselves produced by cells of the apical meristem. 7. Epidermis is covered by a thick layer of cuticle. The testa is also carried up with the cotyledons. Correct answer is option 'C'. The axis of the female cone rapidly increases. Order – Coniferales . They mostly grow in high altitudes (ranging from 1,200 to 3,000 metres). The pollen grain resumes its activity in the spring. Few resin canals are present in the mesophyll… Most photosynthesis takes place in the palisade mesophyll, which is conveniently located at the top of the leaf just under the epidermis. The cone is covered with a lot of resinous secretions. They are mostly present in the temperate regions. It is an evergreen tall tree. Plumule is present towards the inner side. The neck is without any neck canal cells. A single megaspore mother cell is differentiated in the nuc,ellus near the micropylar end. These supply water and minerals to mesophyll tissue upto margins so that the mesophyll cells can carry out photosynthesis. Each microsporophyll has sac like microsporangia (pollen sacs) on the ventral side. Each ovule secretes a mucilaginous drop at the micropylar end. This megaspore mother cell undergoes meiosis to form four megaspores. Can you explain this answer? (a) Scale leaves: The scale leaves are small, membranous and brownish in colour. Broadening by lateral growth is a late process in leaf development. They are present on the main and dwarf shoots. Male Cone The male cones are much smaller. The mesophyll tissue of Pinus needle is -a)Collenchymab)Armed parenchymac)Spongy parenchymad)Transfusion tissueCorrect answer is option 'C'. (a)Branches of unlimited growth: The main branches have an unlimited growth. Body cell divides into two unequal male cells or sperms. Male cells pass down to the tip of the pollen tube. Bark: Phellogen originates in the deeper layers of the cortex. young root is di- to pentarch. The genus Pinus has about 90 species. It makes a large wing for dispersal of seed. The inner, called the “mestome-sheath”, which has few or no chloroplasts, shows thickened cell walls and replaces the missing supporting elements in the vascular bundle. cells. Below the epidermis is a hypodermis which is formed of layers of lignified cells. This assimilation tissue is the primary location of photosynthesis in the plant. A portion of the leaf mesophyll characterized by the cells having little contact among themselves; the apoplast constitutes as much as one-half or more of the volume of the tissue. Further to the inside is a suberized ring of cells called the endodermis, just like in the root, which surrounds the vascular tissue. The broader end of the ovuliferous scale has projection called the umbo. The ground tissue system, the mesophyll, is divided into two regions: the palisade parenchyma, located beneath the upper epidermis and composed of columnar cells oriented perpendicular to the leaf surface, and spongy parenchyma, located in the lower part of the leaf and composed of irregularly shaped cells. Mesophyll cells are found in the plant's leaves. The Pinus is monoecious plant which shows the sporophytic generation. A) Embryo sac done clear. Plant develops both male and female strobili on the same plant. The inner soft bark, or bast, is produced by the vascular cambium; it consists of secondary phloem tissue whose innermost layer conveys food from the leaves to the rest of the plant. The cell walls are infolded or invaginated into the lumen, giving the cells a characteristic lobed shape, 'with arms.' It has balloon like wings. Note the similarity to the Nymphaea leaf and the distinct differentiation between regions of mesophyll. They are called bract scales. The rest are aborted. The male cones are much smaller. Here we go into detail about another 'phyll:' the mesophyll. It consists of a single layer of cells. In Pinus it consists of tracheids and albuminous cells. In between the hypodermis and endodermis is present the mesophyll tissue. Given the link between the proportion of mesophyll tissue and total chloroplast number per needle, this is an important finding, suggesting that the higher photosynthetic rate was likely to result from a larger area of mesophyll tissue. Below is an image of another hydrophytic leaf. The pollen grain has two prothalial cells and an antheridial cell. Mesophyll tissue is made up of two types of cells: palisade parenchyma cells and spongy mesophyll cells. Ø Leaves of Aloe have water storing region in the mesophyll. Megaspore wall encloses the female prothallus. In the leafy shoot this function is mainly localized in the cortical tissue of the leaves, known as mesophyll, Mesophyli. These cells soon disintegrate. In plants, it is part of the mesophyll, where it forms a layer next to the palisade cells in the leaf.The spongy mesophyll's function is to allow for the interchange of gases (CO2) that are needed for photosynthesis. And agree to the ring of vascular bundles this hypodermis is the primary location photosynthesis. Tissue: mesophyll tissue is less developed in xerophytes with less intercellular spaces are. Ovule is directed towards the central axis grain divides in to smaller and larger cells form megaspores... 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