DIURNAL CHANGES OF PHOTOSYNTHETIC CHARACTERISTICS AND CHLOROPHYLL FLUORESCENCE IN CANOPY LEAVES OF FOUR DIPTOCARP SPECIES UNDER EX-SITU CONSERVATION

doi:10.17521/cjpe.2005.0130

Abstract

Abstract:

Dipterocarps dominate the canopy of tropical rainforest of Southeast Asia. They are not only the world's main source of hardwood timber, but their canopy leaves are main organs for global carbon sequestration. Due to anthropogenic activities, many species of dipterocarps are threatened. Because of this situation, ex-situ conservation efforts were employed to conserve the genetic resources of several dipterocarps.
In this study, four dipterocarp species, Dipterocarpus retusus, Hopea hainanensis, Parashorea chinensis (emergent tree species in the rainforest) and Vatica xishuangbannaensis, were selected as study species that had been transplanted in 1981 to an ex-situ dipterocarp conservation forest in Xishuangbanna Tropical Botanical Garden. We measured the diurnal changes in photosynthetic rates, parameters of chlorophyll fluorescence, and morphological traits of their canopy leaves at 15-21 m height during the rainy season of 2004. The results indicated that the maximum photosynthetic rates (P_max) per unit leaf area (7.5 to 18.1 μmol·m ^-2·s^-1) and mass (89.08 to 150.82 nmol·g^-1 DW·s^-1), dark respiration rates (R_d), light saturation point (LSP), light compensation point (LCP) and leaf morphological traits differed significantly among species. Photosynthesis in the four species was depressed at midday. The results revealed that stomatal closure induced by high leaf-to-air vapor pressure deficit (LAVPD) led to photosynthetic depression at midday. Quantum yields of photosystem II (Φ_PSⅡ) in four dipterocarp species decreased significantly at midday, indicating that photoinhibition occurred. However, their PSⅡ values recovered to the early morning value by sunset, indicating that photoinhibition was reversible. The nonphotochemical quenching rate (NPQ) increased significantly in D. retusus, H. hainanensis and V. xishuangbannaensis, indicating that NPQ was used mainly to dissipate excess light energy absorbed by PSⅡ. At midday, the electron transport rate (ETR) in P. chinensis was maintained at high levels, while its photosynthetic rate decreased, suggesting that a large proportion of electrons were allocated to photorespiration. Thus photorespiration was the main mechanism protecting the photosynthetic apparatuses of P. chinensis during the midday photosynthesis depression. Other parameters, such as leaf area, size and density of stomata, and total chlorophyll content, also were measured at the same time. There was a general ranking of P_max in the following order from highest to lowest: D. retusus, P. chinensis, H. hainanensi, V. xishuangbannaensis. Based on the diurnal changes in chlorophyll fluorescence, both leaf stomatal limitations and non-stomatal effects played an important role to prevent photodamage during the midday depression of photosynthesis brought by the high irradiances, high air temperature, low humidity, and so on. The high midday leaf water potential of the four species showed that water limitations had no influence on photosynthetic rates.

Key words: Canopy leaf, Chlorophyll fluorescence, Dipterocarpaceae, Diurnal change, Photosynthesis

MENG Ling-Zeng, ZHANG Jiao-Lin, CAO Kun-Fang, XU Zai-Fu. DIURNAL CHANGES OF PHOTOSYNTHETIC CHARACTERISTICS AND CHLOROPHYLL FLUORESCENCE IN CANOPY LEAVES OF FOUR DIPTOCARP SPECIES UNDER EX-SITU CONSERVATION[J]. Chin J Plant Ecol, 2005, 29(6): 976-984.

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URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2005.0130

https://www.plant-ecology.com/EN/Y2005/V29/I6/976

Figures/Tables 8

References 32

[1]	Airy Shaw HK (1973). A Dictionary of the Flowering Plants and Ferns. 1st edn. Cambridge University Press, Cambridge,375-376.
[2]	Al-Khatib K, Paulsen GM (1989). Enhancement of thermal injury to photosynthesis in wheat plants and thylakoids by high light intensity. Plant Physiology, 90,1041-1048. URL PMID
[3]	Aylett GP (1985). Irradiance interception, leaf conductance and photosynthesis in Jamaican upper mountain rain forest trees. Photosynthetica, 19,323-337.
[4]	Bassow SL, Bazzaz FA (1998). How environmental conditions affect canopy leaf-level photosynthesis in four deciduous tree species. Ecology, 79,2660-2675.
[5]	Bilger W, Bjørkman O (1990). Role of the xanthophylls cycle in photoprotection elucidated by measurements of light-induced absorbance changes, fluorescence and photosynthesis in Hedera canariensis. Photosynthesis Research, 25,173-185. DOI URL PMID
[6]	Brodribb TJ, Holbrook NM (2004). Diurnal depression of leaf hydraulic conductance in a tropical tree species. Plant, Cell and Environment, 27,820-827.
[7]	Cao KF, Booth EW (2001). Leaf anatomical structure and photosynthetic induction for seedlings of five dipterocarp species under contrasting light conditions in a Bornean heath forest. Journal of Tropical Ecology, 17,163-175.
[8]	Cao KF (2000). Water relations and gas exchange of tropical saplings during a prolonged drought in a Bornean heath forest, with reference to root architecture. Journal of Tropical Ecology, 16,101-116.
[9]	Demmig-Adams B, Adams WW Ⅲ (1992). Photoprotection and other responses of plants to high light stress. Annual Review of Plant Physiology and Plant Molecular Biology, 43,599-626.
[10]	Epron D (1997). Effects of drought on photosynthesis and on the thermotolerance of photosystem II in seedlings of cedar (Cedrus atlantica and Clibani). Journal of Experimental Botany, 48,1835-1841.
[11]	Foyer GH, Lelandais M, Kunert KJ (1994). Photooxidative stress in plants. Physiologia Plantarum, 92,696-717.
[12]	Franco AC, Lüttge U (2002). Midday depression in savanna trees: coordinated adjustments in photo-chemical efficiency, photorespiration, CO ₂ assimilation and water use efficiency. Oecologia, 131,356-365. DOI URL PMID
[13]	Genty B, Briantais JM, Baker NR (1989). The relationship between the quantum yield of photosunthetic electron transport and quenching of chlorophyll fluorescence. Biochimica et Biophysica Acta, 990,87-92.
[14]	Grace J, Okali DUU, Fasehun FE (1982). Stomatal conductance of two tropical trees during the wet season in Nigeria. Journal of Applied Ecology, 19,659-670.
[15]	Iio AH, Fukasawa YN, Kakubari Y (2004). Stomatal closure induced by high vapor pressure deficit limited midday photosynthesis at the canopy top of Fagus crenata Blume on Naeba mountain in Japan. Trees, 18,510-117.
[16]	Ishida A, Toma T, Marjenah (1999). Limitation of leaf carbon gain by stomatal and photochemical processes in the top canopy of Macaranga conifera, a tropical pioneer tree. Tree Physiology, 19,467-473. URL PMID
[17]	Ishida A, Toma T, Matsumoto Y, Yap SK, Maruyama Y (1996). Diurnal changes in leaf gas exchange characteristics in the uppermost canopy of a rain forest tree, ( Dryobalanops aromatica) Gaertn. f. Tree Physiology, 16,779-785. URL PMID
[18]	Johnston M, Grof CPL, Brownell PF (1984). Effect of sodium nutrient on chlorophyll a/b rations in C ₄ plants. Journal of Plant Physiology, 11,325-332.
[19]	Jones HG (1992). Plants and Microclimate. 2nd edn. Cambridge University Press, Cambridge,420-428.
[20]	Kenzo T, Ichie T, Ninomiya I, Koike T (2003). Photosynthetic activity in seed wings of Dipterocarpaceae in a masting year: does wing photosynthesis contribute to reproduction? Photosynthetica, 41,551-557.
[21]	Kenzo T, Ichie T, Yoneda R, Kitahashi Y, Watanabe Y, Ninomiya I, Koike T (2004). Interspecific variation of photosynthesis and leaf characteristics in canopy trees of five species of Dipterocarpaceae in a tropical rain forest. Tree Physiology, 24,1187-1192. DOI URL PMID
[22]	Koch GW, Jeffrey SA, Goulden ML (1994). Diurnal patterns of leaf photosynthesis, conductance and water potential at the top of a lowland rain forest canopy in Cameroon: measurements from the Radeau des Cimes. Tree Physiology, 14,347-360. URL PMID
[23]	Krall JP, Edwards GE (1992). Relationship between photosystem II activity and CO ₂ fixation in leaves. Physiologia Plantarum, 86,180-187.
[24]	Leakey ADB, Press MC, Scholes JD (2003). Patterns of dynamic irradiance affect the photosynthetic capacity and growth of dipterocarp tree seedlings. Oecologia, 135,184-193.
[25]	Lee DW, Oberbauer SF, Krishnapilay B, Mansor M, Mohamad H, Yap SK (1997). Effects of irradiance and spectral quality on seedling development of two Southeast Asian Hopea species. Oecologia, 110,1-9. URL PMID
[26]	Ludlow MM, Bjørkman O (1984). Paraheliotropic leaf movement in Siratro as a protective mechanism against drought-induced damaged to primary photosynthesis reactions damage by excessive light and heat. Planta, 161,505-518. URL PMID
[27]	Muraoka H, Tang Y, Terashima I, Koizumi H, Washitani I (2000). Contributions of diffusional limitation, photoinhibition and photorespiration to midday depression of photosynthesis in Arisaema heterophyllum in natural high light. Plant, Cell and Environment, 23,235-250.
[28]	Oberbauer SF, Strain BR, Riechers GH (1987). Field water relations of a wet -tropical forest tree species, Pentaclethra macroloba (Mimosaceae). Oecologia, 71,369-374. URL PMID
[29]	Rascher U, Liebig M, Lüttge U (2000). Evaluation of instant light-response curves of chlorophyll fluorescence parameters obtained with a portable chlorophyll fluorometer on site in the field. Plant, Cell and Environment, 23,1397-1405.
[30]	Roberts J, Cabral OMR, de Aguiar LF (1990). Stomatal and boundary-layer conductance in an Amazonian terra firm rain forest. Journal of Applied Ecology, 27,336-353.
[31]	Scholes JD, Press MC, Zipperlen SW (1997). Differences in light energy utilization and dissipation between dipterocarp rain forest tree seedlings. Oecologia, 109,41-48.
[32]	Zhu H (朱华) (2000). Ecology and Biogeography of the Tropical Dipterocarp Rain Forest in Xishuangbanna (西双版纳龙脑香热带雨林生态学与生物地理学研究(第一版))1st edn. Yunnan Science and Technology Press, Kunming,5-18. (in Chinese with English abstract)

树种 Species	云南龙脑香 Dipterocarpus retusus	海南坡垒 Hopea hainanensis	望天树 Parashorea chinensis	版纳青梅 Vatica xishuangbannaensis
样木平均高度 Height of sampled trees (m)	21 (45)^*	18 (25)	17 (60)	15 (40)
样木平均胸径 DBH of sampled trees (cm)	25.3	22.3	19.0	14.0
中国分布地区和海拔 Regions and altitude distributed in China	云南盈江, 西藏墨脱(600~1 000 m) Yingjiang in Yunnan, Motuo in Tibet (600-1 000 m)	海南崖县、琼中(400~800 m) Yaxian, Qiongzhong in Hainan (400-800 m)	云南补蚌, 广西那坡 (700~950 m) Bubeng in Yunnan, Napo in Guangxi (700-950 m)	云南补蚌, 广西那坡 (800~1 100 m) Bubeng in Yunnan, Napo in Guangxi (800-1 100 m)

树种 Species	云南龙脑香 Dipterocarpus retusus	海南坡垒 Hopea hainanensis	望天树 Parashorea chinensis	版纳青梅 Vatica xishuangbannaensis
样木平均高度 Height of sampled trees (m)	21 (45)^*	18 (25)	17 (60)	15 (40)
样木平均胸径 DBH of sampled trees (cm)	25.3	22.3	19.0	14.0
中国分布地区和海拔 Regions and altitude distributed in China	云南盈江, 西藏墨脱(600~1 000 m) Yingjiang in Yunnan, Motuo in Tibet (600-1 000 m)	海南崖县、琼中(400~800 m) Yaxian, Qiongzhong in Hainan (400-800 m)	云南补蚌, 广西那坡 (700~950 m) Bubeng in Yunnan, Napo in Guangxi (700-950 m)	云南补蚌, 广西那坡 (800~1 100 m) Bubeng in Yunnan, Napo in Guangxi (800-1 100 m)

树种 Species	云南龙脑香 Dipterocarpus retusus	海南坡垒 Hopea hainanensis	望天树 Parashorea chinensis	版纳青梅 Vatica xishuangbannaensis
最大净光合速率 Maximal net photosynthetic rate (P_max)
以单位叶面积表示 On area basis (μmol·m^-2·s^-1)	18.10±1.13^a	14.43±0.52^b	12.97±0.93^b	7.50±0.59^c
以单位干重表示 On dry weight (nmol ·g ^-1 DW·s^-1)	140.10±16.93^a	101.79±2.52^b	150.82±11.32^a	89.08±8.27^b
暗呼吸速率 Dark respiration rate (R_d)
以单位叶面积表示 On area basis (μmol·m^-2·s^-1)	2.08±0.15^a	1.35±0.09^b	1.22±0.03^b	0.70±0.10^c
以单位干重表示 On dry weight (nmol ·g ^-1 DW·s^-1)	13.86±2.06^a	9.13±1.03^a	13.98±0.88^a	8.44±1.15^a
光饱和点 Light satuaration point (μmol·m^-2·s^-1)	791±93^b	1184±109^a	1311±204^a	851±81^b
光补偿点 Light compensation point (μmol·m^-2·s^-1)	15.8±0.9^b	30.4±2.6^a	10.3±2.0^b	11.6±1.8^b
表观量子效率 Apparent quantum yield (μmol·μmol^-1)	0.062±0.005^a	0.034±0.002^b	0.051±0.008^ab	0.031±0.003^b

树种 Species	云南龙脑香 Dipterocarpus retusus	海南坡垒 Hopea hainanensis	望天树 Parashorea chinensis	版纳青梅 Vatica xishuangbannaensis
最大净光合速率 Maximal net photosynthetic rate (P_max)
以单位叶面积表示 On area basis (μmol·m^-2·s^-1)	18.10±1.13^a	14.43±0.52^b	12.97±0.93^b	7.50±0.59^c
以单位干重表示 On dry weight (nmol ·g ^-1 DW·s^-1)	140.10±16.93^a	101.79±2.52^b	150.82±11.32^a	89.08±8.27^b
暗呼吸速率 Dark respiration rate (R_d)
以单位叶面积表示 On area basis (μmol·m^-2·s^-1)	2.08±0.15^a	1.35±0.09^b	1.22±0.03^b	0.70±0.10^c
以单位干重表示 On dry weight (nmol ·g ^-1 DW·s^-1)	13.86±2.06^a	9.13±1.03^a	13.98±0.88^a	8.44±1.15^a
光饱和点 Light satuaration point (μmol·m^-2·s^-1)	791±93^b	1184±109^a	1311±204^a	851±81^b
光补偿点 Light compensation point (μmol·m^-2·s^-1)	15.8±0.9^b	30.4±2.6^a	10.3±2.0^b	11.6±1.8^b
表观量子效率 Apparent quantum yield (μmol·μmol^-1)	0.062±0.005^a	0.034±0.002^b	0.051±0.008^ab	0.031±0.003^b

树种 Species	云南龙脑香 Dipterocarpus retusus	海南坡垒 Hopea hainanensis	望天树 Parashorea chinensis	版纳青梅 Vatica xishuangbannaensis
正午水势 Midday leaf water potential (MPa)	-0.058±0.003^b	-0.071±0.007^a	-0.094±0.012^a	-0.072±0.004^ab
相对含水量 Relative water content (%)	98.0±0.4^a	99.6±0.3^a	93.9±0.6^b	98.8±0.2^a
叶绿素含量 Total chl content (mg·g^-1 FW)	1.39±0.29^b	1.97±0.17^a	2.46±0.37^a	1.53±0.12^b
叶绿素a/b比值 Ratios of chl a/b	2.71±0.05^a	2.50±0.07^ab	2.20±0.17^b	2.61±0.08^a
比叶面积 Specific leaf area (cm²·g^-1)	76.85±5.02^b	72.23±2.70^b	116.65±7.20^a	118.40±2.90^a
气孔密度 Stomatal density (mm^-2)	89.5±1.79^c	90.0±0.19^c	105.2±1.89^b	158.6±1.79^a
保卫细胞长度 Guard cell length (μm)	25.41±0.69^a	22.10±0.47^b	21.96±0.23^b	19.77±0.50^c
平均叶面积 Average leaf area (cm²)	403.8±26.7^a	66.6±2.5^b	47.6±2.1^c	42.9±2.1^c