Growth What is growth How plant grow Growth

Growth • What is growth ? • How plant grow ? • Growth potential ?

Growth • Change in dry weight = Net photosynthesis = Gross photosynthesis - Respiration Loss (Dead) - Translocation • Dw 2 - Dw 1

Potential crop growth • Dw = net photosynthesis • Maximum amount of incident PAR is intercepted • Albedo loss c. 8. 3 % • Latent heat loss c. 10 % • 10 mol of PPFD is captured by 1 mol CO 2 • Respiration (maintenance ) c. 33 % • 1 mol of photosynthate c. 30 g • c. 8% of Dw comes from MINERALS

REFLECTED 25 SOLAR RADIATION 100 ABSORBED 10 SCATTERED 9 DIRECT SWSR 50 - 55 ALBEDO 8 LONG WAVE Evaporation, convection, conduction ABSORBED 14

Absorbed radiation

Potential crop growth • • • Daily SWSR Total quanta (2. 063 m mol J-1) Albedo loss (8. 3%) Heat loss (10 %) Available quanta CO 2 fixed Respiration loss (33%) Net photosynthesis Net assimilate Net biomass 17. 20 MJ m-2 d-1 35. 48 mol. m-2 d-1 - 2. 94 mol. m-2 d-1 - 3. 55 mol. m-2 d-1 29. 00 mol. m-2 d-1 2. 9 mol. m-2 d-1 - 0. 96 mol. m-2 d-1 1. 94 mol. m-2 d-1 58 g. m-2 d-1 63 g. m-2 d-1

Compare potential CGR vs actual (g m-2 d-1) Potential Alfalfa Maize Millet Pineapple Potato Rice Soybean Sugarcane. C 4 65 23 52 54 28 37 36 36 C 3 C 4 CAM C 3 C 3 38

How to increase crop growth • • • increase Photosynthesis minimize Respiration increase LAI to increase PAR interception increase CO 2 minimize other constrains 3 3 water stress mineral deficiency climatic hazard pest & disease

Growth analysis • Blackman, 1919 • Wt = W 0 e RT • RGR = 1/w x dw / dt ) = ln w 2 - ln w 1 ) / (t 2 - t 1(

Growth analysis • What is it ? • How can we analysis the growth ? • Is it related to photosynthesis ? • Conventional vs. new method ?

Classical or coventional GROWTH ANALYSIS • RGR = 1/W x d W / d t /1) = ) A x d W / d T) x (A/W( = W 2 - W 1) / (A 2 - A 1) x (ln A 2 - ln A 1) / (t 2 - t 1) x (A 2 + A 1) / 2 *(W 2 +W 1( = NAR x LAR

Application for crop growth analysis p. Crop growth = n x Plant growth p. CGR = n x NAR x LAR = NAR x LAI p. CGR = Crop Growth Rate อตราการเจรญเตบโตของพชปลก = (W 2 - W 1) / (t 2 - t 1( n = number of plant / area p. LAI = Leaf Area Index สดสวนของพนทใบพช ตอพนทปลกพช

Leaf and canopy for radiation interception • Leaf area • LAI • leaf inclination • canopy structure • leaf angle • row orientation • leaf orientation • row spacing & plant population

Application for crop productivity • Loomis & Williams (1963( e 1. e 2. e 3. e 4. e 5. e 6. e 7 • Biomass = (Monteith 1972( • Ludlow (1980( Y bio. = �(intercepted radiation). eb CGR = mean (Qi). )g m-2 d-1) eb (MJ m-2 d-1). ( g MJ-1(

Radiation conversion efficiency Monteith (1972) e p e p sun and earth geometry radiation transmission radiation spectral change CO 2 fixation CO 2 diffusion Radiation interception Respiratiion

Further analysis o. CG (biomass) = total incident radiation x % light interception by the canopy x eb o. CGR = mean daily incident radiation x % light interception by the canopy x eb

Q 0 Qi Q 1 Light sensor 0 Qi = Q 0 - Q 1 Qi Qi Q 1 Light sensor 1

Light attenuation under canopy s Monsai & Saeki (1963) applied BEER-Lambert’s law s Light attenuation through a medium depends on THICKNESS and PROPERTIES of the medium. s I / I 0 = e -KL ln (I / I 0) = -KL s I and I 0 is Light under and above the canopy of leaf area = L s K = extinction coefficient of the canopy

Application J DW = Qi. e b J DW = Q 0. % interception. e b J DW = Q 0. I 0(1 - e -KL ). e b

Biomass production of rice with two planting systems (direct sown vs. transplanting) After : Rangsan , 1995 Dry weight (g m-2) DM = 17. 9 + 3. 20 PAR DM = 25. 5 + 2. 77 PAR Intercepted PAR (MJ m-2)

Related terms always found in the literatures H Incident radiation , PAR , SWSR H Intercepted radiation , PAR H Absorberd radiation , PAR H Light interception efficiency H Radiation use efficiency H Light use efficiency / Radiation conversion efficiency H Carbon balance

KNOWLEDGES WISDOM when there is learning INFORMATION when relate to other data & or other information Plant Hypothesis Assumption Theory Question Crop abilities to apply knowledges to solve problems and should occur naturally Plant / crop growth Of varience RGR, NAR, LAR X + SD CGR, LAI etc. Analysis Raw DATA / Attribute leaf area (cm 2/plant or m 2) Leaf DW (g/plant or m 2) Stem DW Total DW Measurement