Plants Flashcards
what is gross primary productivity?
photosynthetic CO2 fixation
what is net primary productivity?
GPP- autotrophic respiration
what is autotrophic respiration?
respiration of roots
how much of earths land cleared for agriculture?
40%
When did photosynthesis evolve?
3.5Ba
When was the great oxidation event?
2.5Ba
Whats unique about anoxygenic photosynthesis?
Doesn’t use water as a electron donor (uses sulphide, iron hydrogen instead
What is anoxygenic photosynthesis?
bacterial photosynthesis occurring under anaerobic conditions using photosynthetic ETC (in a non-cyclic mode)
What are the 2 lineages of green plants?
chlorophytes and streptophytes
What did land plants evolve from?
Streptophytes
Are land plants mono or para phyletic?
monophyletic- from streptophytes
What makes up the viridaeplantae?
chlorophytes and streptophytes
what lifecycle did land plants evolve from?
haplodiplonic
what happened 407 Ma?
first plant ecosystems
What is sporopollenin?
protect the pollen grains from external damages such as rain,high temp. Sporopollenin forms the outercovering of the exine & it is the most resistant organic material on the Earth
What is parenchyma?
composed of thin-walled cells and makes up the photosynthetic tissue in leaves, the pulp of fruits, and the endosperm of many seeds.
What is sclerenchyma?
thick, lignified secondary walls, lack cell contents at maturity, and occur throughout all plant tissues adn STRUCTURAL SUPPORT
What is collenchyma?
composed by elongated living cells of uneven primary thick walls It provides support, structure, mechanical strength, and flexibility to the petiole, leaf veins, and stem of young plants, allowing for easy bending without breakage.
What is th eepidermis?
outermost, protoderm-derived layer of cells covering the stem, root, leaf, flower, fruit, and seed parts of a plant
What are adventitious roots?
form from stem tissues, generally as a result of damage or removal of the primary root system
How are plants highly regenerative in response to sessility?
silent meristems restore growth after damage |+ they can regrow virtually any organ
What are primordia?
organ, structure, or tissue in the earliest stage of development.
what is leaf shape determined by?
serration, lobes and leaflets
are meristems determined by clonal origin or position?
position- meristem. was cut and regrow to look almost identical
What are the 3 types of meristematic tissue?
root apical (RAM), shoot apical(SAM) and cambria
What does pleiotropic mean?
actions other than those for which the agent was specifically developed
What do shuttle proteins do?
transfer phosphate
Why can synthetic hormones stimulate a stronger response?
plants aren’t equipped for catabolism
How are plant hormones used in agriculture?
regeneration of explants- fruit ripening (ethylene) and plant height ( prevent plant lodging)
What are the 2 different types of hormone perception receptors?
membrane associated and soluble
What are the 2 types of cell division?
Periclinal- increase cell layer
Anticlinal- increase number of cells per layer
What establishes polarity and cell elongation?
phosphorylation cascade
What is the hypophysis?
gives rise to some of the root cells.
What determines primordia positioning?
PIN’s sending auxin towards primordium apex
What does the Auxin maxima direct?
cell divisions e.g. emergence of lateral roots
What is vernalisation?
can only flower after a period of cold- down regulated FLC expression
What do giberellins influence?
Long and short day flowering ( needed for long day)
What is a universal transmissible signal molecule to promote flowering?
FLORIGEN
What are leptoids?
bundles of living cells known as leptoids which carry sugars and other nutrients in solution. - like phloem BUT NOT
How are sporangia produced?
by meiosis in sporangia
Is ferm / monilophypte sporophyte diploid or haploid?
diploid- produce spores by meiosis
What is circinate venation?
1 side of leaf grows faster than other, then catches up = unfurls
Why are Azolla watermoss grown in rice paddies?
to fertilise field and they have anabaeba azollae nitrogen fixing cyanobacterium living in cavities
What is sapromyophily a form of?
deceit pollination