10 Venation (Damarlanma) = yaprakta venlerin dağılımı Netted-venation = bir veya birkaç dominant midvein vardır aralarda daha ince ağsı damarlar bulunur (dicotlar)Pinnately-veined leaves = midrib denen ana damar, burdan orjinlenen secondary veinlerPalmately-veined leaves = veinler blade tabanından ayrılır (maple).Paralel venation = monocots (grasses, cereal grains); venler birbirine paralelDikotomus venation = midrib veya büyük venler yok; benzer ebatta cok sayıda ven çatal oluşturarak tabandan iki farklı yöne gider, fan şekilli yaprak
18 3. Detachment abscission zone: Parenkima hücreleri bazi cell wall enzimleri salgılar (glucanases and pectinases); self digestHücler su alır şişer
19 TRANSPIRATIONPlants must supply water to all their tissues. It moves from the roots up the stem to the leaves by capillary action.The evaporation of water vapor from plant surfaces is called transpiration.Stoma neden var
20 Stomanın açılıp kapanması transpirasyonu düzenler Az Su, düşük sıcaklık, ışık ; kapalıgündüz açık gece kapalıguard cells
22 GUARD CELLS AND PLANT HOMEOSTASIS kidney-shaped with thick inner walls and thin outer walls.When they become full of water (turgid) the unevenness of the walls causes them to bow outward and the stomate opens.When they lose water they become less turgid and the stomate closes.Guard cells gainand lose water byosmosis.
23 Stomatal guard cells Environmental factors are sensed by guard cells Light intensity, temperature, relative humidity, intercellular CO2 concentrationIntegrated into well defined responsesIon uptake in guard cellBiosynthesis of organic molecules in guard cellsThis alters the water potential in the guard cellsWater enders themSwell up %
24 Plants and water Bitkiler dehidrasyondan uzak durmak ister water conservation X CO2 assimilationBazı yapılar su dengesinde önemli1: iyi gelişmiş root– to get water from soil2: suya direnç götermeyen taşıma– xylem3: leaf cuticle – reduces evaporation4: stomata – controls water loss and CO2 uptake5: guard cells – control stomata.
25 Habitatlara göre bitkiler Mesophytes: plants adapted to a habitat with adequate waterXerophytes: plants adapted to a dry habitatHalophytes: plants adapted to a salty habitatHydrophytes: plants adapted to a freshwater habitat
27 Xerophytes Sunken stoma Hair, air current Waxy cuticle waterproof Rolled leafDaha az stomaKüçük yaprakİyi kök sistemi
28 small leaf surface area less surface area for evaporation AdaptationHow it worksExamplethick cuticlestops uncontrolled evaporation through leaf cellssmall leaf surface arealess surface area for evaporationconifer needles, cactus spineslow stomata densitysmaller surface area for diffusionsunken stomatamaintains humid air around stomatamarram grass, cactistomatal hairs (trichores)marram grass, couch grassrolled leavesmarram grass,extensive rootsmaximise water uptakecacti
29 Left and right Epidermis of the cactus Rhipsalis dissimilis. Left: View of the epidermis surface. The crater-shaped depressions with a guard cell each at their base can be seen.Right: X-section through the epidermis & underlying tissues. The guard cells are countersunk, the cuticle is thickened. These are classic xerophyte adaptations.
30 Transverse Section Through Leaf of Xerophytic Plant
34 Specialized or Modified Leaves In pine trees, the leaves are adapted to living in a dry environment too.Water is locked up as ice during significant portions of the year and therefore not available to the plant; pine leaves possesssunken stomata,thick cuticlesneedle-like leaveshypodermis, which is an extra cells just underneath the epidermis –
35 he xylem and phloem in the center are surrounded by transfusion tissue composed of a mixture of parenchyma cells and short tracheids. The outer boundary of the transfusion tissue is marked by a single row of conspicuous cells comprising the endodermis. Notice also, depending on the species of pine, that the xylem and phloem may be in two adjacent patches (vascular bundles), or there may be a single vascular bundle. Much of the remaining tissue of the leaf is mesophyll, which is not divided into palisade and spongy layersThe xylem of conifers consists of tracheids and lacks vessel members. The phloem tubes lack the one-to-one relationship with a companion cell derived from the same progenitor cell. Instead certain nearby parenchyma cells are modified into albuminous cells which presumably load/unload the phloem in a manner similar to companion cells. The vessels are enclosed in tranfusion tissue consisting of parenchyma cells and tracheids. Note the resin canals.
36 Cotyledons or “seed leaves” Çinlenen tohumun ürettiği ilk yaprakBol miktarda besin (endospermden gelir)
37 TendrilsGarden PeaTendrils – yaprağın blade kısmı indirgenmiş, sarılma özelliği
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