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WVIT 233 Final Exam Study guide
Questions and Answers
Souce of assimilates - Answer-Organic compounds produced by photosynthesis and nutrient assimilates
Transported from a place of manufacturing
Source is any plant organ that exports these materials
souce of assimilates in a plant are: - Answer-Leaves
Green berries
Green shoots
Also any storage structures that deliver assimilates
Canes
Cordons
Trunk
Roots
sink of assimilates - Answer-Sink is a non photosynthetic plant organ
All sources began their life as a sink
,These sources needed resources to grow to be able to produce
Insufficient photosynthate to supply its own needs
sink of assimilates in plants are - Answer-Expanding leaves
Root tips
Shoots
Reproductive organ (flowers and developing fruit/seeds)
Plants make an initial investment in stores stable life in the future
ideal canopy - Answer-15 leaves
42 inches of growth
2 clusters per shoot
leaves and photosynthetic abilities - Answer--Leaves in spring make a positive gain in photosynthetic
production earlier than in late season
-Late season leaves add very little amount of photosynthetic contribution
-One reason why limiting late season leaves growth helps to ripen fruit and provide more carbohydrates
for storage.
-Competition is not good at that time
leaves and sink/source of assimilate - Answer--A leaf can begin to export assimilates at about ⅓ of its
final size
-However still importing until about ½ the size
-Bidirectional movement of assimilates
-Basal(lower) levels will begin to export when 6-7 leaves are above
-These assimilates are moving to growing tips
, -Exports much of its carbohydrates to growing areas of shoots (energy goes low→ high from roots to top
of grapevine)
-Just produce enough for their own needs
Leaves and length of life - Answer--Leaves live about 40 days (for photosynthetic capacity)
Woody tissues - Answer--Regarded as a sink for most of the time because they do not photosynthesize
-However they store all necessary assimilates that were produced earlier
-Remobilize during the spring and summer months
-They provide the earliest energy source for spring and summer months
-They provide the earliest energy source for spring growth at bud break
-Initial triggering of the remobilization is from gibberellin acid
Also provide a buffer when extreme growing conditions exist
transportation of assimilates - Answer--Must be flexible to be able to supply both the source and sink
demands
-The translocation of solutes are moved via the phloem
-More precisely the sieve tubes that are able to move greater amounts of solutes
-Major compounds that are translocated are water and sucrose in grapevines
-Sucrose make 50-70% of the sap osmotic pressure
-Other compounds that are moved through phloem
-Potassium, amino acids, organic acids (malate and tartrate)
-This changes as senescence begins
-Higher concentrations of minerals are moved from leaves into woody tissues to be recycled
-Almost all hormonal compounds are transported by phloem
WVIT 233 Final Exam Study guide
Questions and Answers
Souce of assimilates - Answer-Organic compounds produced by photosynthesis and nutrient assimilates
Transported from a place of manufacturing
Source is any plant organ that exports these materials
souce of assimilates in a plant are: - Answer-Leaves
Green berries
Green shoots
Also any storage structures that deliver assimilates
Canes
Cordons
Trunk
Roots
sink of assimilates - Answer-Sink is a non photosynthetic plant organ
All sources began their life as a sink
,These sources needed resources to grow to be able to produce
Insufficient photosynthate to supply its own needs
sink of assimilates in plants are - Answer-Expanding leaves
Root tips
Shoots
Reproductive organ (flowers and developing fruit/seeds)
Plants make an initial investment in stores stable life in the future
ideal canopy - Answer-15 leaves
42 inches of growth
2 clusters per shoot
leaves and photosynthetic abilities - Answer--Leaves in spring make a positive gain in photosynthetic
production earlier than in late season
-Late season leaves add very little amount of photosynthetic contribution
-One reason why limiting late season leaves growth helps to ripen fruit and provide more carbohydrates
for storage.
-Competition is not good at that time
leaves and sink/source of assimilate - Answer--A leaf can begin to export assimilates at about ⅓ of its
final size
-However still importing until about ½ the size
-Bidirectional movement of assimilates
-Basal(lower) levels will begin to export when 6-7 leaves are above
-These assimilates are moving to growing tips
, -Exports much of its carbohydrates to growing areas of shoots (energy goes low→ high from roots to top
of grapevine)
-Just produce enough for their own needs
Leaves and length of life - Answer--Leaves live about 40 days (for photosynthetic capacity)
Woody tissues - Answer--Regarded as a sink for most of the time because they do not photosynthesize
-However they store all necessary assimilates that were produced earlier
-Remobilize during the spring and summer months
-They provide the earliest energy source for spring and summer months
-They provide the earliest energy source for spring growth at bud break
-Initial triggering of the remobilization is from gibberellin acid
Also provide a buffer when extreme growing conditions exist
transportation of assimilates - Answer--Must be flexible to be able to supply both the source and sink
demands
-The translocation of solutes are moved via the phloem
-More precisely the sieve tubes that are able to move greater amounts of solutes
-Major compounds that are translocated are water and sucrose in grapevines
-Sucrose make 50-70% of the sap osmotic pressure
-Other compounds that are moved through phloem
-Potassium, amino acids, organic acids (malate and tartrate)
-This changes as senescence begins
-Higher concentrations of minerals are moved from leaves into woody tissues to be recycled
-Almost all hormonal compounds are transported by phloem
