Dry matter partitioning What is it ? How is it measured ? For what ? Source & sink relationship

Dry matter distribution or partitioning Biomass or dry matter Y biol. Economic yield Y econ. Dry matter allocation or distribution Harvest Index Ear Translocation Photosynthate Stem or shooot Root

Source - Sink relationship Flower , Seed, Fruit Stem, Root SOURCE Leaves Reproductive / Vegetative growth Photosynthesis / Light interception

Dry matter distribution or partitioning ระหว่าง organ ในต้นพืช เช่นใบ ลำต้น ดอก ผล หรือ ราก ระหว่างเซลล์ หรือเนื้อเยื่อ ในส่วนอวัยวะพืช เช่น supporting cells กับ meristematic cell (tissue) ระหว่าง orgenel ในเซลล์พืช สามารถอธิบายได้ด้วยสัดส่วน (Dry weight ratio or %) หรือ สัมประสิทธิของการกระจายน้ำหนักแห้ง ( h : partitioning coefficient)

hl, hs, hr What does it mean ? Ability of plant to accumulate Photosynthate in a particular part (each has specific function and value) Mechanism of plant in response to certain environment

Translocation of Photosynthate Can be measured by using radioisotope eg. 14C , 13C 12 , 15N 32P Hydrolytic pressure gradient depend on activity and size of supply (SOURCE) and demand (SINK)

SOURCE - SINK relationship Translocation Feedback inhibition STRENGTH / CAPACITY SIZE x ACTIVITY Absolute rate of change in Wl STRENGTH / CAPACITY SIZE x ACTIVITY Absolute rate of change in Wg

Potential Source Capacity LAI LAID, leaf longivity Increase light interception Extinction coefficient of canopy Increase Photosynthesis rate

Potential Sink Capacity Reprodutive phase Flowering bud initiation No. of flower developed to be a fruit No. of fully developed fruit Fruit size Rate of fruit or seed growth

Vegetative growth vs Reproductive growth Do vegetative growth enhance SOURCE SIZE ??? depend on Dry matter partitioning (Dry Weight Ratio or Partitioning coefficient) high LWR ie. ability to produce more PHOTOSYNTHATE at an expense of Root or Stem weight, but ability to find water or minerals may be reduced or less ability to flower

Reproductive stage Flower, fruit or seed are ACTIVE SINK HI = Yecol. / Y biol. Distribution index = Change in Y ecol. / Change in Y biol. after anthesis

Reproductive stage Current Photosynthate Storage Photosynthate Remobilization EAR 1 st SOURCE SINK 2 nd ROOT

Yield components Size of the SINK Nr, No. of reproductive unit Ng, No. of grain per reproductive unit Wg, Grain weight each component is determined at different times of vegetative and reproductive stages

Application in crop production SOURCE or SINK LIMIT ?? ALTER SOURCE Defoliation Shading Thining Light suppliment, Pruning Fetilizer Weed control

Application in crop production ALTER SINK Root pruning Deflowering or debuding Fruit thinning Watering and Fertilizer application

แนะนำ paper ให้อ่าน Board, J.E. and Qiang, Tan. 1995. Assimilatory capacity effects on soybean yield components and pod number. Crop Sci. 35(2) : 846-851. Cirilo, A.G. and F.H. Andrade. 1994. Sowing date and maize productivity. I crop growth and dry matter partitioning. II. Kernel number determination. Crop Sci. 34(4) : 1039-1046. James, J H. 1994. Canopy characteristics associated with deficient and excessive cotton plant population density. Crop Sci. 34(5) :1291-1297. Jiang, H. and D.B. Egli. 1995. Soybean seed number and crop growth rate during flowering. Agron. J. 87(2) : 264-267. Jonathan, Lynch and N.S. Rdrignez, H. 1994. Photosynthetic nitrogen-use efficiency in relation to leaf longevity in common bean. Crop Sci. 34(4) : 1284-1290.

แนะนำ paper ให้อ่าน Kining, J.R. and D.P. Knievel. 1995. Response of maize seed number to solar radiation interception soon after anthesis. Agron. J. 87(2) : 228-234. Pau, W.L., J.J. Canberato, R.H. Mall, E.J. Kamprath and W.A. Jackson. 1995. Altering source-sink relationship in prolific maize hybrids: Consequences for nitrogen uptake and remobilization. Crop Sci. 35(2) : 836-845. Pendelton,B.B., G.L. Teetes and G.C. Paterson. 1994. Phenology of sorghum flowering. Crop Sci. 35(4) : 1263-1266. Pettigrew, W.T. and W.R. Meredith Jr. 1994. Leaf gas exchange paratmeters vary among cotton genotypes. Crop Sci. 34(3) : 700-705.

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References Gardner, F.P., R.B. Pearce and R.L. Mitchell. 1985. Physiology of Crop Plants. Iowa State Univ. Press. Ames. 327. Incoll, L.D. 1977. Field studies of photosynthesis monitoring with 14 CO2. in (Landsberg, J.J. and C.C. Cutting eds) Environmental Effects on Crop Physiology. Academic Press. London : 137-155. Loomis, R.S. and Connor, D.J. 1992. Crop Ecology: Productivity and Management in Agricultural Systems. Cambridge Univ. Press. Cambridge. 538 pp. (S589.7 L66 1992) Milthrope, F.L. and J.Moorby. 1979. An Introduction to Crop Physiology. 2nd ed. Cambridge Univ. Press. Sydney. 244pp. Raghavendra, A.S. 1991. Physiology of Trees. John Wiley & Sons, Inc. New York 21-51pp. (QK711.2 P49 1991) Sheehy, J.E. and Johnson, I.R. 1988. Physiological model of grass growth. in (Jones, M.B. and Lazenby, A. eds) The Grass Crop: The Physiological Basis of Production. Chapman and Hall. London: 243-275. (SB197 G77 1988) Wardlaw, I.F. 1980. Translocation and source-sink relationships. in (Carlson, P.S. ed) The Biology of Crop Productivity. Academic Press. New York :