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 # ~- x0 A8 n% z$ w8 X1 LC.B.S. Teh* 4 r/ y7 _" c: \+ ~4 ?* FDepartment of Land Management, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, + ^% k- n# Y4 a7 j2 OMalaysia / T" N3 Q: F2 L) _/ h5 Abstract3 c7 V( r1 Q9 k; p
One of the properties of canopy architecture is leaf shape, and its effect on solar radiation7 |2 g) j- y( c! b8 m
interception by a plant is little understood and studied. Consequently, this study was to evaluate) _; {% v+ u! M p) N( O; H
the effect of six leaf shapes on both direct and diffuse solar radiation interception using a. V$ I( @8 v7 X( c. o- } ]/ d
detailed 3-D solar radiation model. Six hypothetical plant prototypes were computer-generated % s+ ]2 g5 l% g* V6 G& M. b3 @10 so that each prototype was equal to each other in all aspects; only the leaf shape for each# h. \- R8 x; h }) {& M" x# ?0 ]; L1 S
prototype was varied. The leaf shapes selected were round (RD), square (SQ), triangle (TR), - }. I) O, B |% Pinverted triangle (ITR), ellipse (EL) and lobe (LB). Computer simulations revealed that leaf4 c' ^; s. C( v# r5 f- } v( q. x
shape did have an effect on direct and diffuse solar radiation interception. However, its effect " ~" C2 {- @2 x( C6 j7 Uwas to a rather small extent of not more than 11% increase in solar radiation interception. The T7 J6 {/ X' d15 mean hourly interception of solar radiation by the prototypes decreased in the following 5 A* i2 R0 K3 P! f9 |3 L- X$ }' Rmanner: (ITR ≈ EL) > (RD ≈ SQ ≈ TR ≈ LB). Although leaf lobbing is often hypothesised to, Y4 b2 T. }* E) q
produce deeper sunflecks within the canopy, this study however revealed that leaf lobbing per: Q4 U! R& a# [* S, d& F1 y+ h# G$ z T) D
se had no effect on solar radiation interception. All properties being equal, solar radiation ?" G; H% R) f( Cinterception could be increased by having leaf shapes that are: 1) long and narrow, 2) broader at 1 w# |0 o3 ^) \) W8 Z/ v R! W" s20 the apex than at the basal, and 3) supported by leaf petioles. These three conditions increase, Q/ Y( u0 K |8 E# I4 E3 [/ U
solar radiation interception by causing the canopy to be spread out more uniformly in the aerial # g2 w2 N" j% m# h/ K' wspace; this, in turn, means less leaf clustering and self-shading. However, the effect of leaf" a' e! w* X% D+ h
shape on solar radiation interception decreases for near or full canopy cover because at this - u5 |8 s; u+ i2 S) w$ k$ ustage, the canopy is already intercepting solar radiation at near maximum capacity. Leaf shape& A6 H% c x2 W. A4 K6 q
25 also did not affect the diurnal variation of direct and diffuse solar radiation interception. This / g5 B& v) e8 g( b) P) j' T' ]study may help to better select crop varieties having the “proper leaf form” for optimum plant # o" t8 K* v3 L9 Q* Cproduction, as well as to better understand plant adaptation mechanisms in response to w1 z+ b$ e* H( L5 i
environmental stresses. 2 b* J4 Y3 o, E. @, AKeywords: leaf shape; solar radiation; Beer’s law; canopy architecture ' l: i# \' Q( P/ L x2 J7 m* W" j5 E: J1 x
* o4 z w* v T( K6 @# f: {
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