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 0 n8 f2 w0 l* Q8 e1 v( z: cC.B.S. Teh* & X% T Y8 c x8 A# J2 D) wDepartment of Land Management, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, 0 g, q% g, n; W$ B9 g2 kMalaysia 3 W3 W' J H) O/ }7 m3 D1 X7 ?5 Abstract 1 g/ o% E7 a/ mOne of the properties of canopy architecture is leaf shape, and its effect on solar radiation h A( c4 D1 Q* k% h( U, ~
interception by a plant is little understood and studied. Consequently, this study was to evaluate % J0 B+ T2 t! q; hthe effect of six leaf shapes on both direct and diffuse solar radiation interception using a- H0 B" o- ~" e. l2 J
detailed 3-D solar radiation model. Six hypothetical plant prototypes were computer-generated # M6 `+ }2 G0 y; @10 so that each prototype was equal to each other in all aspects; only the leaf shape for each _& s+ z& y! X& W: E* u2 wprototype was varied. The leaf shapes selected were round (RD), square (SQ), triangle (TR),6 R: @! S1 V1 \6 J' f; c
inverted triangle (ITR), ellipse (EL) and lobe (LB). Computer simulations revealed that leaf " P$ s9 W. c5 h, mshape did have an effect on direct and diffuse solar radiation interception. However, its effect; q# R2 u& b1 c* C
was to a rather small extent of not more than 11% increase in solar radiation interception. The 6 Q0 l0 z. ]9 w. {15 mean hourly interception of solar radiation by the prototypes decreased in the following % L# x5 R* r2 E/ b' r3 wmanner: (ITR ≈ EL) > (RD ≈ SQ ≈ TR ≈ LB). Although leaf lobbing is often hypothesised to # Z/ d' k2 A: {2 B- Pproduce deeper sunflecks within the canopy, this study however revealed that leaf lobbing per 7 R+ J' \4 J, O5 B+ sse had no effect on solar radiation interception. All properties being equal, solar radiation: F( C& {& V. ~& _ g
interception could be increased by having leaf shapes that are: 1) long and narrow, 2) broader at 4 i* K4 h* I0 z' h9 A x$ Q20 the apex than at the basal, and 3) supported by leaf petioles. These three conditions increase 1 R6 }, r9 K! Ssolar radiation interception by causing the canopy to be spread out more uniformly in the aerial 2 C/ B9 _* {! ^$ Z# s; Y7 sspace; this, in turn, means less leaf clustering and self-shading. However, the effect of leaf ! F6 b7 M0 c8 zshape on solar radiation interception decreases for near or full canopy cover because at this * U9 D1 I+ ?/ r9 O9 L: @0 }stage, the canopy is already intercepting solar radiation at near maximum capacity. Leaf shape ' }, F+ y/ F, a$ S% G25 also did not affect the diurnal variation of direct and diffuse solar radiation interception. This % J0 o2 t% b& z y% |6 d2 Lstudy may help to better select crop varieties having the “proper leaf form” for optimum plant7 W* `; R* P* b
production, as well as to better understand plant adaptation mechanisms in response to ) m, E. |2 S7 U8 r M0 |environmental stresses.8 Q1 S3 Y0 E6 r! z0 I" Z; |
Keywords: leaf shape; solar radiation; Beer’s law; canopy architecture 9 y u, z6 N( i3 R+ h; y- U6 [( _$ b2 y0 R( O# V/ n1 `+ c8 J
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