Term
| There are three soil horizons in the ground. The uppermost, A horizon, contains ___; B horizon contains ___ ; C horizon contains rocks of ___ of which the soil is formed. |
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Definition
decomposing organic matter
clay and dissolved elements
parent matter |
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Term
| Plants can obtain ions from the soil through ___. Plant roots release protons which bind to negatively charged ___, allowing some of its cations to come off and be absorbed by the plant (K+ is the most abundant). The protons may also come from ___ acid (H2CO3) in the soil. |
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Definition
ion exchange
clay
carbonic |
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Term
| One problem is that besides some ammonium in A horizon, ___ is hard to obtain from ion exchange. Because of this, plants must get it from bacteria who reduce nitrogen containing compounds. |
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Definition
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Term
There is a cycle of nitrogen in the environment. Bacteria called ___ turn molecular nitrogen into ammonia or ammonium. ___ can turn this ammonium into nitrite or nitrate. Plants then reduce it back to ammonium in a process known as ___ or backteria act as ___ and bring it back to molecular oxygen.
Plants also use ammonium is a nitrogen source. |
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Definition
nitrogen fixers
Nitrifiers
nitrate reduction
denitrification |
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Term
| Plants can't obtain molecular nitrogen from the environment because its ___ is too stable. Instead, they obtain ___ from bacteria in the water and on land who fix it. A famous mutalism occurs between the bacteria Rhizobium and the ___ plant, where small nodules (swellings) occur in the plant roots where the bascteria is present. Lichens, rice & Azolla (a fern) and woody plants with actinobacteria are also nitrogen mutalisms. |
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Definition
triple bond
ammonium
legume
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Term
| The ___ bacteria with the legume plant is a famous nitrogen based mutalism. The bacteria enters the roots through hairs. Flavanoids (Vitamin P) are released from the plant to cause the bacteria to transcribe node genes, which cause the cells to divide and nodules to form. |
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Definition
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Term
| Some parasitic plants, who may not be able to photosynthesize, obtain nutrients like nitrogen by inserting their ___ organs into their plant prey. The mistletoe and dwarf mistletoe are an example of this parasitic plant. |
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Definition
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Term
Plants can also obtain nitrogen from eating insects. The following dicots do this:
-___ close shut when hairs are activated
-___ attract insects then prevent them from escaping with downward pointing hairs
-___ emit sticky sugar solutions so that the insects get stuck |
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Definition
venus fly traps
pitcher plants
sundews |
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Term
| Nitrogen (or iron) deficient leaves will appear yellow, because they are needed in ___ pigments. So without chlorophyll active, the leaf does not appera green anymore. ___ deficiency causes leaves to appear purple, and ___ deficiency causes leaves to appear orange. |
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Definition
chloyophyll
phosphorus
potassium |
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Term
| ___ crops leads to soil depletion, because the part taken out often contains the most nutrients (like potatos, which are tubers - energy compartments). |
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Definition
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Term
| Adding excess nutrients to the environment (through things like fertilizer) can cause ___ plants to become very abundant, and when they die, microbes decompose them as they consume ___. |
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Definition
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Term
| During early plant growth, plants respond to cues initiated and maintained by two regulators: ___ (two regulators). |
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Definition
hormones and photoreceptors
Note that environmental cues and the plant's genome may also have effects. |
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Term
| Tropic responses involve a change in growth direction. Phototropism is growth in response to ___. Thigmotropism is growth of tendrils in response to ___. Gravitropism is a change in growth in response to ___. Pollen tubes of flowering plants display ___ chemotropism, because they are growing towards the stimulus. |
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Definition
light
phototropism
gravity
positive |
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Term
| Auxin is a hormone which allows cell elongation through loosening the cell wall by pumping ___ into it. |
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Definition
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Term
| A hormone which allowed the plant to display phototropism (growth response to ___) was isolated at the ___ of plants. Went's experiment found that you could remove this hormone then put it back on and the plant would redisplay phototropism. |
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Definition
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Term
| It was found that auxin, a ___, represses axillary bud growth (growth in ___). The closer the apical meristem is (where auxin is present), the less the plant's width increases. This is why the tips of trees are thinner than the bottoms. |
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Definition
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Term
| Gibberellins are a plant ___, which promote seed ___ and overall growth. |
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Definition
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Term
| Auxin, a hormone, inhibits ___, which is when old leaves fall of the stem. |
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Definition
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Term
| Cytokinin is a growth ___. High ratios to auxin promote rapid cell division and cause formation of ___. With low ratios to auxin, the formation of ___ is promoted. Cytokinin also causes light-requiring seeds to ___, promotes ___ growth over elongation and delays aging of leaves. |
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Definition
hormone
shoots
roots
germinate in the dark
lateral |
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Term
| Ethylene is a growth ___ that promots senescence (ripening, aging). |
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Definition
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Term
| Brassinosteroids are a type of growth ___, which promote cell and pollen tube elongation and vascular tissue differentiation, but it inhibits root ___. It was first isolated from the mustard family. |
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Definition
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Term
| Hormones are regulatory molecules that act at ___ concentrations, often far away from where they were created. |
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Definition
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Term
| Photoreceptors are pigments involved in developmental processes that are associated with ___. Blue-light receptors (ex. ___) mediate the effects of blue light, and phytochrome mediate the effects of ___ light. |
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Definition
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Term
| Photomorphogenesis are physiological and developmental processes controlled by ___. |
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Definition
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Term
| Phytochrome is a pigment that mediates the effects of ___ colored light. The pigment has two forms: Pr and Pfr. Pr absorbed ___ and Pfr absorbs ___ light. The active form, which triggers many processes, is ___. |
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Definition
red light
red
far-red
Pfr |
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