Angiosperm Characteristics. Mangals & Salt Marshes- Vascular Plant Tidal Communities

Transcription

1 May 28 I will let you know which day you are going!!! Please also submit a good question about your presentation to me electronically. These question will be uploaded to the website as a study guide for the final. June 2 & 4 -Student Presentations Powerpoint Presentation 5-7 minutes. Both people must speak during the presentation. Intro, Material & Methods, Results & Discussion Mangals & Salt Marshes- Vascular Plant Tidal Communities Low energy coastal regions such as estuaries or coastal habitats protected by barrier islands June 6- Lab practical, Notebooks & pressings due! June 10- Final 7:30-10:30pm 1 2 Switching gears from algae to angiosperms Angiosperm Characteristics holdfast blade Less tissue specialization Happy in salt water stem flower leaves roots/rhizomes More tissue specialization Stressed by salt water 3 1) Pigments: chl a &chl b cartenoids- B-carotene, violaxanthin 2) Chloroplast structure: 2membranes stacks of 2-6 3) Storage product: starches:amylose & amlyopectin 4) Flagella: None depend of pollinators, wind, birds, bugs, bats 5) Mitosis: double fertilization sperm cell undergoes mitosis 1 sperm fuses with egg to form zygote 1 sperm fuses with polar nuclei to form endosperm - nutritional source for growing zygote 4 1

2 Brief history of photosynthetic organisms on earth 3.45 bya = Cyanobacteria appear and introduce photosynthesis 1.5 bya = first Eukaryotes appeared (nuclear envelope and ER thought to come from invagination of plasma membrane) 0.9 bya = first multicellular algae (Rhodophyta - Red algae) 800 mya = earliest Chlorophyta (Green algae) mya = plants on land derived from Charophyceae 250 mya = earliest Heterokontophyta (Brown algae) 100 mya = earliest seagrasses (angiosperms) DOMAIN Groups (Kingdom) 1.Bacteria- cyanobacteria (blue green algae) 2.Archae 3.Eukaryotes 1. Alveolates- dinoflagellates 2. Stramenopiles- diatoms, heterokonyophyta 3. Rhizaria- unicellular amoeboids 4. Excavates- unicellular flagellates 5. Plantae- rhodophyta, chlorophyta, seagrasses 6. Amoebozoans- slimemolds 7. Fungi- heterotrophs with extracellular digestion 8. Choanoflagellates - unicellular 5 9. Animals- multicellular heterotrophs 6 Types of flowering plants Plantae phycoerythrin Unicellular, freshwater Chloroplast peptidoglycan Chl b, Starchamylose & amlyopectin Embryo, cuticle Glaucophytes Rhodophyta Chlorophytes Charophytes Land Plants 1. Mesophytes/ Glycophytes- grow where freshwater is available & lack specialized adaptations that prevent water loss 2. Hydrophytes- live in water, partially or fully submerged (seagrass) 3. Xerophytes- have, morphological, anatomical, & reproductive adaptations to aid in the retention of water ( mangroves & salt marsh plants 1. Halophytes- adaptations to prevent water loss & can grow in saline habitats 1. Facultative- do not require saline conditions 2. Obligate- specific requirement for sodium to complete their life cycle 7 Adapted from Sadava

3 Zonation Patterns- physical factors and biotic interactions Zonation Patterns physical factors biotic interactions biotic interactions physical factors Dave Lohse Salt Marshes -typically areas of natural salttolerant herbs, grasses, or low shrubs growing on unconsolidated sediments bordering saline water bodies whose water levels fluctuates tidally Over 400 species- 9 maritime formation Salt water Salt Marsh Zonation soil salinity and flooding (Juncus) Distichlis Frankenia Salicornia Spartina Graciliaria Zostera Land 11 Relatively high nutrients - detritus Soil anoxia Hypersaline to evaporation Disturbance from beach wrack 12 3

4 Some adaptations for salt marsh living: Salt stress Epidermal salt glands Salt vacuoles store salt in stem, drop stems seasonally Thick cuticle reduce contact Succulent Soil anoxia: Aerenchyma = tissue with air spaces Lacunae = space in stem to root Some adaptations for salt marsh living: Soil Anoxia & Substrate Type: Rhizomes- thick anchoring & delicate absorbing roots, bind unconsolidated sediments to reduce erosion, release oxygen reduce anaerobic conditions suppress methane production Ecological Roles of Salt Marshes Spartina foliosa native cord grass 1. Primary Production- below ground biomass 90%, 10 x sequestration rates of terrestrial forest, 90% in soil so long term blue carbon storage 2. Food Sources- detrital food chain 3. Habitats-important nursery habitats for marine fish 4. Stabalization of Sediments- root systems 5. Filtration- removal of organic waste by marshes lowers the sediment and nutrient loading to adjacent shores Monocot in the grass family- Poaceace 3m tall culms (stems) Culms & leaves only 1/3 to 1/10 of biomass Salt glands excrete excess salt, leave salt crystals on leaves Have lacunae tissue in stems/roots allows oxygen transport to roots (often aneorobic soil) Occur in lowest parts of salt marsh

5 Spartina foliosa/alterniflora HYBRID Problem in salt marsh communities in the SF Bay & Puget Sound Negative impacts: Changes physical environment (oxygen, nutrients, hydrology, accretion rates) Displaces native cordgrass (S. foliosa) and pickleweed Changes invertebrate community (much less rich) Decreases available water chokes water channels, decreases foraging area for birds Eradication is difficult Grosholz lab, UC Davis Sarcocornia pacifica pickle weed Dicot- Chenopodiaceae Succulent- water containing cells Concentrates salt in tissues, drops stems every year Often parasitized by dodder, Cuscuta salina Occurs in the low-mid marsh Distichlis sp, the salt grass Has salt glands Occurs in the high marsh Juncus spp, the spiny rush Occurs in the high marsh

6 East coast: An experiment examining the effects of salt stress on species interactions: (Bertness and Shumway 1993, AmNat) Positive interaction = Facilitation Negative interaction = Competition The players: Spartina zone gets flooded more, less saline Juncus zone becomes hypersaline thru evaporation Distichlis co-occurs with both Spartina and Juncus Research question: Is the nature of species interactions mediated by the physical environment? Distichlis Juncus 21 Spartina Bertness and Shumway 1993, AmNat 22 The experiment: Remove all vegetation in plots of both zones Remove neighbors (potential competitors or facilitators) in half of plots Water (alleviates salt stress) in half of plots Count percent cover of target species, see whether target species increases or decreases based on neighbors and physical stress Juncus The experiment: Remove all vegetation in plots of both zones Remove neighbors (potential competitors or facilitators) in half of plots Water (alleviates salt stress) in half of plots Count percent cover of target species, see whether target species increases or decreases based on neighbors and physical stress Juncus Treatments in each zone: - Water + Neighbor - Water - Neighbor Control + Water + Neighbor Watered + Water - Neighbor Spartina Bertness and Shumway 1993, AmNat 23 Spartina Bertness and Shumway 1993, AmNat A FACTORIAL DESIGN 24 6

7 The results: Spartina zone (less Spartina outcompetes Distichlis in both watered and control plots Distichlis more abundant when neighbors are removed. The results: Spartina zone (less Spartina outcompetes Distichlis in both watered and control plots Distichlis more abundant when neighbors are removed. Competition is prevailing interaction Juncus zone (more Juncus zone (more modified from Bertness and Shumway 1993, AmNat 25 modified from Bertness and Shumway 1993, AmNat 26 The results: Spartina zone (less Spartina outcompetes Distichlis in both watered and control plots Distichlis more abundant when neighbors are removed. Competition is prevailing interaction The results: Spartina zone (less Spartina outcompetes Distichlis in both watered and control plots Distichlis more abundant when neighbors are removed Competition is prevailing interaction Juncus zone (more Control plots presence of neighbors increased abundance of Juncus = facilitation Juncus zone (more Control plots presence of neighbors increased abundance of Juncus = facilitation Watered plots Neighbors modified from Bertness and Shumway 1993, AmNat 27 modified from Bertness and Shumway 1993 decrease abundance of Distichlis 28 = competition 7

8 Negative interaction Positive interactions The conclusion: Alleviating salt stress shifts nature of interactions from facilitative to competitive Bertness and Shumway 1993, AmNat Mangals Associational defenses Neighborhood habitat amelioration Physical stress Consumer pressure 29 modified from Bertness and Callaway 1994,TREE Mangroves & associated tidal marsh communities 30 Mangal taxonomy Domain Eukaryote Kingdom/Clade Plantae Phylum/Division Magnoliophyta - angiosperms Class Magnoliopsida Order Malpighiales Family Rhizophoracea Genus Rhizopora species mangle- red mangrove Mangal Distribution 31 - Tropical tidal habitats - 40 species of Mangroves dominate 75% of the tropical coastline between 25 N & 25 S - Orders Myrtales & Rhizophrales make up 50% of the species 32 8

9 Mangal Genera Share the following features: 1. Species restricted to mangals. 2. Trees exhibit major role in community structure. 3. Morphological specializations, including aerial roots & vivipary 4. Plants exhibit salt- exclusion physiology 5. Taxonomic isolation from terrestrial relatives at the level of genera Mangrove Forest Classification 1 Coastal Fringe- along protected shoreline berms 2 Overwash- low intertidal 3 Riverine- along streams and rivers and extend several miles inland 4 Basin- occur in a depression behind a berm or fringing mangals, connected to streams or tidal creeks 5 Scrub- occur where abiotic conditions are severe due to limited water 6 Hammock- inland tropical wetlands, isolated by fresh water Adaptations of Mangroves 1. Mechanical adaptations for attachment in soft sediment 2. Aerial roots are common & specialized for diffusion of gases to subterranean portions. 3. Vivipary- germination of seedlings while fruit remains attached to tree 4. Seeds & seedlings can survive in salt water & disperse via salt water 5. Xerophytic modifications- survive with little fresh water 6. Halophytic modifications- survive with high amounts of salt

10 Mangrove Leaves evergreen complex leaf anatomy thick outer walls & cuticles salt is accumulated in leaves causing succulence and eventually shed glandular hairs- function in salt excretion lenticles- cork warts secrete water & chloride hypodermis upper layer contains tannins lower layer contain hydrocytes- water containing cells Mangrove trunks & bark lenticles- dense masses of cells that results in breaks in the bark - function in gas exchange - critical for root survival Zonation patterns 40% of root is used for gas exchange Upper limit determined by biotic interactions Lower limit determined by abiotic factors

11 Rhizopora mangle- red mangrove Red Bark & Leathery Leaves Vivipary-seedling germinate from fruit while attached to tree Lacunae- gas exchange Enlargement of airspaces Air spaces forming channels in leaves, stems and roots Also have a structural role Stilt roots- develop from the stem prop - develop from a branch drop Lacunae- gas exchange Seagrass Leaf Diagram lacunae Bundle sheath- containing phloem & xylem Avicennia germinans- black mangrove Hair on leaves- salt secretion Cryptovivipary-embryo grows out of the seed but not the fruit before dropping aerenchyma Wheat stomata Fiber bundles 43 Aerenchyma tissue- gas exchange Cable root with Pneumatophores- extend cm above root function in gas exchange 44 11

12 Aerenchyma tissue- gas exchange Avicennia marina- white mangrove Formed by cell separation Mechanism for root aeration in low oxygen concentrations Stilt or Cable roots 45 Nectaries at base of leaves secrete sugar Hair on leaves- salt secretion 46 Mangal Macroalgae important primary producers epiphytic algae on roots = to the leaf litter from the tree Water Regulation & Osmoregulation facultative halophytes- competitive exclusion limits them to saline habitats slow growth because they spend a lot of energy dealing with salt salt secretors- Avicennia- 33% of the salt non secretors- Rhizophora - exclude 90% of salt

13 Ecological roles of Mangals 1. Coastal Resilience 2. Filtering land runoff 3. Stabilization of sediments 4. Trapping sediments 5. Primary Production 6. Nursery Habitats Coastal Resilience & Mangroves Storm surge- low pressure & high winds raise water level at the coast -peak water levels can exceed 7m in height flooding Mangroves can reduce storm surge and surface waves Loss of Mangals extraction, pollution & reclimation Has lead to declines of finfish & commercial shrimp these species depend on detrital & benthic microalgae Long term pollution from oil spills cause mutations in the trees 1) Pigments: Angiosperm Characteristics 2) Chloroplast structure: Habitat Loss seagrass 1.5% yr mangroves 1.8% yr tropical forests 0.5% yr 3) Storage product: 4) Flagella: 5) Mitosis: