标题: 对太阳辐射的拦截叶形状的影响 The effect of leaf shape on the interception of sol [打印本页] 作者: ゞ_轻描丶幸福的 时间: 2014-12-8 17:09 标题: 对太阳辐射的拦截叶形状的影响 The effect of leaf shape on the interception of sol The effect of leaf shape on the interception of solar radiation 3 }% a7 D8 i/ N& G* Y: _1 d/ X) TC.B.S. Teh*! a; S" D' ~+ y; z! t6 O
Department of Land Management, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor,: n; b9 \' ?' t2 K
Malaysia1 n5 q" L0 d2 `3 a# _
5 Abstract ; ^6 J/ |$ m5 Z. C# R+ V4 K+ yOne of the properties of canopy architecture is leaf shape, and its effect on solar radiation 5 O, `. ~* g& e' Kinterception by a plant is little understood and studied. Consequently, this study was to evaluate; \; q% p9 a/ L4 E* X' n+ t+ ~
the effect of six leaf shapes on both direct and diffuse solar radiation interception using a T, }: S" B) w; Q7 |
detailed 3-D solar radiation model. Six hypothetical plant prototypes were computer-generated : u1 f, i. j! t10 so that each prototype was equal to each other in all aspects; only the leaf shape for each. _8 w' Q/ ~) X% w6 `6 s" `
prototype was varied. The leaf shapes selected were round (RD), square (SQ), triangle (TR),9 N6 a+ w% \& M5 `6 L/ v: ^* s
inverted triangle (ITR), ellipse (EL) and lobe (LB). Computer simulations revealed that leaf' D! p/ Z* c$ M7 {9 c) @
shape did have an effect on direct and diffuse solar radiation interception. However, its effect + k, a. |6 ~' F2 R* F7 Vwas to a rather small extent of not more than 11% increase in solar radiation interception. The* { A. ?8 X. H% d6 r& y0 Z6 ~
15 mean hourly interception of solar radiation by the prototypes decreased in the following ! w H9 B7 Y& b3 p' y- i% Smanner: (ITR ≈ EL) > (RD ≈ SQ ≈ TR ≈ LB). Although leaf lobbing is often hypothesised to 9 x7 q( k$ t# Y& m3 T" |produce deeper sunflecks within the canopy, this study however revealed that leaf lobbing per $ g, U# T0 |3 [) s- o5 Q- Fse had no effect on solar radiation interception. All properties being equal, solar radiation L- l; p7 {8 }' ]( m' [
interception could be increased by having leaf shapes that are: 1) long and narrow, 2) broader at' ]* o+ u) z8 g1 h
20 the apex than at the basal, and 3) supported by leaf petioles. These three conditions increase , }+ O9 ^* k. {/ l; ]6 isolar radiation interception by causing the canopy to be spread out more uniformly in the aerial ! O6 P; e, C0 i: c. y/ Z% pspace; this, in turn, means less leaf clustering and self-shading. However, the effect of leaf5 `" i/ U+ f. r
shape on solar radiation interception decreases for near or full canopy cover because at this' u8 S$ U8 K8 C8 G6 o5 M5 y
stage, the canopy is already intercepting solar radiation at near maximum capacity. Leaf shape & B! U \2 E: J8 P; P25 also did not affect the diurnal variation of direct and diffuse solar radiation interception. This9 g# L8 K7 A1 z2 U1 @' {5 A( x3 `
study may help to better select crop varieties having the “proper leaf form” for optimum plant$ K& I' O+ V3 T+ Z6 k: u* i3 s
production, as well as to better understand plant adaptation mechanisms in response to ) {' [- `4 m2 y* Wenvironmental stresses.3 S1 q7 l/ y1 y
Keywords: leaf shape; solar radiation; Beer’s law; canopy architecture9 ]7 ]/ f$ `9 t: b- e/ r. G
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