25Incas used them asfuel sourceCushion plants – Coropuna, Peruvian altiplano
26Note the leavesPuya Raimondi, Pastoruri (Peru)Blooms evey 40 years!
27Alpine environment summarized: Cold + windysnowy!short growing seasonlow nutrient availabilityHigh UV radiationHow do plants survive in these conditions?
28Plant adaptation to alpine environment (1) evolutionary adaptation(2) ontogenetic modifications, which are non-reversible during the life of an individual(3) reversible adjustment, often termed “acclimation”
294 things plants need: Liquid water nutrients warmth light Limiting factors in alpine and arctic tundraLimiting factor in arctic tundra only
30Adaptations to cold 1) Cushion plants: grow in small, rounded humps conserve heatreduce wind chill
31Adaptations to cold 2) Develop a blanket of white hairs protect them from cold at nightWhite to reflect radiation during the daye.g. Giant Lobelia, in Kenya
32Adaptations to cold 3) Keep dead leaves on the stem prevents ground from freezinge.g. Groundsel
33Adaptations to cold 4) Grow short and small to avoid harsh winds and crushing snowthe air temperature is warmer 10-15cm above the soil.
34Adaptations to cold5) Grow in balls that roll around w/frost heave, eg. Kenya mossdeal w/expansion and contractionof soil due to freezing and thawing.Stone circles
35Adaptations to cold 6) Rosette plants cabbage-like leaves surround a central budwinter: central bud is protected by the remaining vegetation.
36More adaptations to cold high investment into belowground biomass (high root:shoot ratio)tolerance to low temperatures(= intolerance of high temperatures)
37Cold-tolerant species examples Heaths: hard evergreen leaves that can withstand drying winds and cold temperatures.Common heaths: cranberries, blueberries, and rhododendrons
38II. Adaptations to dry conditions Many high mountains plants are succulents, with water stored in thick leaves;minimize evaporationE.g. cactus
39Adaptations to High UV irradiance Cover their leaves with white hairs (reflect the suns rays).Some plants contain a red pigment called anthocyanin which absorbs UV sunlight before it has a chance to damage the leaves.
40Short growing season Cold nights short daylight hours 180 days/year Adaptation:start to grow as soon as the snows meltsstore food during the summer monthspollination strategies?The Fireweed's seeds are plume-shaped. This allows them to rideon the wind before falling to the groundwhere they can take root.
41Summary LIMITATIONS ADAPTATION Cold - grow short, close to ground - grow horizontally-cushion treeswind - grow in clumps (island trees)low nutrients -carnivorousUV -white hairs; antocyaninlow growing seasons - grow fast; store nutrients;-pollination strategiesdry -wax leaves