Exam 2 Transport In Plants Flashcards

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0
Q

¥w=¥p+¥s

A

Total water potential of a plant = pressure potential and solute potential

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1
Q

Transpiration

A

Process where plants absorb water through roots and give off water vapor through pores in their leaves.

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2
Q

Water moves from areas

A

High to low ¥w

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3
Q

Adhesion

A

Attraction between water and polar groups of other molecules

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4
Q

Cohesion

A

Attraction between molecules

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5
Q

Water movement through xylem is…

A

Passive

Neg. pressure in xylem

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6
Q

Water evaporates into intracellular spaces and exits the stomatal pores by diffusion :

A

The concentration of water vapor inside the lead is higher than that of the atmosphere.

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7
Q

Opening and closing of the stomata…

A

Regulates transpiration

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8
Q

ABA (abscisic acid)

A

Plant hormone that triggers closure of stomata.

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9
Q

Soil solution

A

[K+] plant cells&raquo_space;[K+] in the soil solution

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10
Q

When they reach xylem,

A

Minerals move to the shoot with the transpiration stream and are incorporated into the tissues of the shoot

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11
Q

Phloem transports organic molecules:

A

Sucrose, amino acids, and some hormones
Movement is from sources to sinks.
Movement only in one direction.

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12
Q

Sources:

A

Places from where molecules are exported.

Eg. Mature leaves

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13
Q

Sinks

A

Places where import of substance occurs.

Eg. Roots, young leaves, fruits, seeds, growing parts of the plant.

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14
Q

Mass flow

A

Substances move by a difference in hydrostatic pressure between the source (high pressure) and the sink(low pressure).

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15
Q

At a source, solutes are loaded into the phloem, drives water into phloem, resulting in

A

High pressure

16
Q

At a sink, solutes are unloaded, water moves out, resulting in

A

Water moves out and the pressure is low.

17
Q

Macronutrients obtained from air or water:

A

C, O, H

More than 1g/kg of plant dry matter

18
Q

Macronutrients obtained from the soil (soil solution)

A

N, P, S, K, Ca, Mg

19
Q

Micronutrients obtained from the soil ( soil solution)

A

Cl, Mn, Mo, B, Cu, Fe, Ni, Zn

Less than 100mg/kg

20
Q

Functions of essential elements:

A

Part of molecules, e.g. N in proteins and Nucleic acids, P in ATP, Mg in chlorophyll, Fe in cytochromes

Necessary for the activity of certain enzymes. E.g. Mg^2+ and Mn^2+ are cofactors for several enzymes.

Osmotic balance, e.g. K+ and Cl-

21
Q

Localized necrosis

A

Dead tissues, symptom of mineral deficiency. Low K

22
Q

Chlorosis,

A

Yellow areas in the leaves , low N

Symptom of mineral deficiency

23
Q

Curling of leaves, sign of min. Def.

A

Low Mg

24
Q

Stunted growth, sign of min. Def.

A

Low Ca^2+

25
Q

Humus

A

Decaying organic matter

26
Q

Organic matter helps

A

In the retention of cations (K+, Ca2+, Mg2+) and represents a reservoir of nutrients

27
Q

Mineral particles

A

Sand: 20-2000 micrometers in diameter
Silt: 2-20 micrometers in diameter
Clay: less than 2 micrometers in diameter

28
Q
Pores are occupied by water or air.
Small particles (clay) help:
Large particles (sand) aid:
A

Retention of water and cations

Aid in drainage of the soil

29
Q

Nutrient cycle losses; leaching of nutrients

A

Eg. Loss of NO3- and SO4-

30
Q

Nutrient cycle losses; burning vegetation

A

Burning liberates N and S as a gas harvesting crops.

31
Q

Replenishment :

A

Fixation of nitrogen, ex. Symbiotic association between legumes and rhizobia.
Addition of fertilizers, inorganic (N, P, K) organic (manure, compost)