The effect of leaf shape on the interception of solar radiation # b* U ~* R1 h+ X2 P+ B0 LC.B.S. Teh*7 E$ e8 f; v$ X7 h& G
Department of Land Management, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor,2 s o$ I5 h& r; `3 a
Malaysia 4 a% X7 J7 F% _' i. D, K9 t3 D2 }5 Abstract & W9 ]# D# U. \! gOne of the properties of canopy architecture is leaf shape, and its effect on solar radiation5 H* V4 V7 z' y& m: W0 }; _" N
interception by a plant is little understood and studied. Consequently, this study was to evaluate/ Y7 K, }/ L4 _- u
the effect of six leaf shapes on both direct and diffuse solar radiation interception using a 3 e v2 H* B, y8 |( E/ Gdetailed 3-D solar radiation model. Six hypothetical plant prototypes were computer-generated7 l+ k) F) t9 c- H& Q5 t6 ^% L3 V
10 so that each prototype was equal to each other in all aspects; only the leaf shape for each % s4 G$ C3 c& G4 J7 ~prototype was varied. The leaf shapes selected were round (RD), square (SQ), triangle (TR),& c1 w/ I. R) { b8 X
inverted triangle (ITR), ellipse (EL) and lobe (LB). Computer simulations revealed that leaf9 y8 `1 r2 K! _! O
shape did have an effect on direct and diffuse solar radiation interception. However, its effect( c; x' I5 H) v# S9 |2 W: _
was to a rather small extent of not more than 11% increase in solar radiation interception. The 5 x/ M& f2 E C15 mean hourly interception of solar radiation by the prototypes decreased in the following , o! O! v. `; i# h6 P/ `+ i( r) Nmanner: (ITR ≈ EL) > (RD ≈ SQ ≈ TR ≈ LB). Although leaf lobbing is often hypothesised to 5 s/ U z6 m2 I: Wproduce deeper sunflecks within the canopy, this study however revealed that leaf lobbing per # T9 B8 h H% j6 B# Q) M% I6 dse had no effect on solar radiation interception. All properties being equal, solar radiation 7 {# U9 H8 s7 O; E5 Hinterception could be increased by having leaf shapes that are: 1) long and narrow, 2) broader at/ @! A6 U8 t. `* N" n
20 the apex than at the basal, and 3) supported by leaf petioles. These three conditions increase Z1 F3 }" y; L1 n9 l
solar radiation interception by causing the canopy to be spread out more uniformly in the aerial6 t- ?4 X7 T5 Q) m& R
space; this, in turn, means less leaf clustering and self-shading. However, the effect of leaf" K6 m, I: R: z4 K
shape on solar radiation interception decreases for near or full canopy cover because at this ; t% c' _+ u, \4 i3 }8 Estage, the canopy is already intercepting solar radiation at near maximum capacity. Leaf shape7 }. J ^0 @+ M3 A$ n ^1 V7 v6 z' R
25 also did not affect the diurnal variation of direct and diffuse solar radiation interception. This 4 @! q+ A8 V4 q/ q! Hstudy may help to better select crop varieties having the “proper leaf form” for optimum plant ' \. X9 g5 \& R; ^8 ^* Z! m- `+ \8 Tproduction, as well as to better understand plant adaptation mechanisms in response to 8 a+ p8 r+ b/ j1 henvironmental stresses.) {+ g4 W9 S" Q3 ?+ r( e+ b
Keywords: leaf shape; solar radiation; Beer’s law; canopy architecture; E1 w- ~3 D7 e- m) Q# e! ]
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发表于 2014-12-8 17:09
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