Characteristics Light intensity (per cent of full sun)
100 55 40 25
Thickness of tissue (μm)
Palisade parenchyma 71.7 73.3 56.0 54.8
Spongy parenchyma 182.5 159.2 135.0 135.0
Lamina 283.3 264.3 220.2 216.7
Palisade and spongy ratio 0.39 0.46 0.42 0.41
Stomata
Frequency (mm-2leaf area) 351.5 301.3 291.5 231.4
Chlorophyll content (mg/g FW)
Chlorophyll a 1.269 1.399 1.496 1.503
Chlorophyll b 0.572 0.599 0.622 0.704
Chlorophyll a/b ratio 2.22 2.34 2.41 2.13
Photosynthetic
Light compensation point
(μmol. s-1 m-2)
6 3 --- 2
Light saturation point
(μmol. s-1 m-2)
1200-1400 1000-800 --- 600-800
Max. photosynthetic rate
(μmol. s-1 m-2 of CO2)
6.8 7.6 --- 6.4
Table 2. Growth of longkong seedlings after two years experienced under different light intensity conditions.
Parameters Light intensity (per cent of full sun)
100 55 40 25
Leaflet length (cm) 9.4 a1 12.1 b 11.3 ab 10.1 ab
Leaflet width (cm) 3.4 a 3.9 ab 4.1 b 3.6 ab
Leaflet area (cm2) 33.5 a 43.3 b 46.9 b 35.4 ab
Leaflet/leaf 7.3 a 8.2 b 8.2 b 7.4 a
Leaf area (cm2) 239 a 355 b 385 b 253 a
Leaf/plant 24.3 a 42.3 b 45.2 b 42.8 b
Leaf area/plant (m2) 0.53 a 1.38 bc 1.61 c 1.11 b
Height of plant (cm) 143 a 175 b 185 b 178 b
Width of plant canopy (cm) 53.3 a 81.7 b 90.0 b 95.3 b
Trunk diameter (cm, 15 cms above ground) 2.34 ab 2.52 b 2.53 b 2.07 a
Leaf dry weight/plant (g) 51.0 a 116.6 b 121.8 b 98.0 b
Twigs dry weight/plant (g) 188.8 a 273.1 b 300.4 b 190.4 a
Above ground plant dry weight (g) 239.8 a 389.7 b 422.2 b 288.4 a
Leaf and stem dry weight ratio 0.27 a 0.43 ab 0.42 ab 0.55 b
1 Values