seeds

Question 1

advantage of small seed

Answer 1

persistent seeds, enable plants to have a larger seed production and a longer persistence in the soil seed bank

Question 2

advantage of large seed

Answer 2

-emerge from deep soils or penetrate litter layer
-reserves to support respiration
-reserves to recover from tissue loss
-better access to light and soil resources
-escape size-dependent mortality
-better mammal dispersal

Question 3

who has bigger and smaller seeds?

Answer 3

light demanding smaller, shade tolerant bigger (though there are exceptions)

Question 4

what is the difference in seed rain between gaps and understory

Answer 4

understory dominated by zoochorous species, gaps more wind dispersed species. understory was more varied in seed rain

Question 5

how many seeds in seed bank tropical forest

Answer 5

mature 3000/m2 secondary forest 15000/m2

Question 6

which seeds are found in soil seed bank the most

Answer 6

seeds from small seeded, fast growing light demanding species because they are viable longer.

Question 7

four factors that can delay germination of rainforest seeds

Answer 7

hard seed coat,
low seed water content
small size and slow embryo development
chemical germination inhibitors

Question 8

orthodox seeds

Answer 8

seeds that can be stored for long time, usually low seed water content (<7%)

Question 9

recalcitrant seeds

Answer 9

rapid germinating seeds that can’t handle drying out. should not be used for reforestation. examples common oak and horse chestnut

Question 10

what are germination cues

Answer 10

light quantity and quality, temperature and soil humidity

Question 11

photoblastic germination

Answer 11

pioneer species should stay dorment in the shade and germinate only when enough sunlight is available (as indicator that there is a gap in the canopy). but might not be true

Question 12

how does a hard seed coat delay germination

Answer 12

by limiting oxygen exchange or physically restraining embryo growth.

Question 13

what may pioneers need to germinate instead of light

Answer 13

bare, litter free mineral soil

Question 14

what can you do to improve seed bank/rain

Answer 14

topsoil removal to mobilize seed bank and provide litter free germination bed for small-seeded species, if species are not present in seed bank you can plant fruit bearing trees to improve input of seed rain.

Question 15

what is the bottleneck in life cycle of a tree

Answer 15

seedling phase (up to 80% mortality)

Question 16

definition of seedling

Answer 16

still has seed, or depends on seed reserves

Question 17

what can seed energy reserves be

Answer 17

starch or oils and other lipids. lipid is more concentrated, starch more common

Question 18

why do so many seedlings die?

Answer 18

small (easy to damage)
high tissue quality (attractive for herbivores)
little access to resources (due to small leaves and root systems, therefore suffer more from shade, drought and nutrient dificiencies)
little reserves

Question 19

how do seedlings react to heterogeineity (gradients in light, nutrients, water etc.)

Answer 19

acclimation or adaption

Question 20

acclimation

Answer 20

short term phenotypic response of individuals to climatic conditions

Question 21

adaption

Answer 21

longer term genetic responses of populations of species to environmental conditions

Question 22

functional equilibrium hypothesis

Answer 22

plant resource allocation to capture the resource in limiting supply (eg lack of light should cause a plant to focus on growing leaves)

Question 23

growth survival trade off

Answer 23

species from high resource environments should focus on growing to outcompete others (aquisitive traits), species from low resource environments should focus on survival (conservative traits).

Question 24

what does a growth analysis do

Answer 24

allow you to analyse the relative growth rate of plants in terms of its underlying components

Question 25

relative growth

Answer 25

growth scaled to relative plant size

Question 26

what determines relative growth

Answer 26

Biomass accumulation, morphology and physiology

Question 27

growth analysis formula

Answer 27

RGR= NAR * LAR or (LMF * SLA)

Question 28

NAR

Answer 28

Net assimilation rate

Question 29

LAR

Answer 29

leaf area ratio

Question 30

LMF

Answer 30

leaf mass fraction

Question 31

SLA

Answer 31

specific leaf area

Question 32

how do plants invest in low light conditions

Answer 32

thin and soft leaves with large SLA, as a result high LAR

Question 33

how do plants invest in high light conditions

Answer 33

with high irradiance there is more transpiration, and water and nutrients are limiting. plants invest in roots. this gives more water and higher phosotyntheic ability, which together with the light causes high NAR. the low LAR is offset by high NAR, causing higher growth rates in high light.

Question 34

what determines carbon gain

Answer 34

irradiance levels, leaf area, light capture efficiency and photosynthetic characteristics

Question 35

what does RGR summarise

Answer 35

carbon balance at whole plant level

Question 36

characteristic difference: pioneers

Answer 36

high in everything, except leaf mass/area, stomatal size, allocation to leaves, bole taper, seed size and stand density

Question 37

what determines carbon loss

Answer 37

respiration rate, herbivory, turnover of plant parts

Question 38

characteristic difference: shade tolerant species

Answer 38

low everything, except leaf mass/area, stomatal size, allocation to leaves, bole taper, seed size and stand density

Question 39

why don't shade tolerant species maximise leaf area?

Answer 39

high SLA leaves are less protected, more susceptible to phatogens, herbivory and physical damage)

Question 40

what is the major respitory drain for seedlings

Answer 40

leaves

Question 41

pioneers/shade tolerant, who has higher NAR?

Answer 41

pioneers, though it's not useful unless in full light

Question 42

do pioneer outgrow shade tolerants in shade?

Answer 42

yes

Question 43

what mostly determines nature of plant defenses

Answer 43

particular site characteristics of the ecosystem of the plant

Question 44

where is carbon allocated

Answer 44

to the organ that captures the most limiting resource

Question 45

stemwood

Answer 45

contains both living (sapwood) and dead tissue (heartwood)

Question 46

when does Amax peak

Answer 46

halfway through the growing season for decideous species, declines with leaf age for coniferous species

Question 47

how much water does a tree transpire

Answer 47

of the hundred liter water used, only 2,5% is used and the rest is transpired

Question 48

what do stomata doe

Answer 48

when they open they aquire co2 but lose water

Question 49

angiosperm wood

Answer 49

three tissue types: vessels, fibres and parenchyma cells

Question 50

gymnosperm wood

Answer 50

tracheids and parenchyma

Question 51

tracheid

Answer 51

wood tissue for water transport (found in gymnosperms)

Question 52

parenchyma cells

Answer 52

found in wood, for transport, carbon- and water storage

Question 53

vessels and fibres

Answer 53

found in angiosperms, vessels for water transport and fibres for strength and sometimes water storage

Question 54

cavitation

Answer 54

water going from liquid to gas phase (inside xylem)