Báo cáo khoa học: "Influence of shade on photosynthetic gas exchange of 7 tropical rain-forest species from Guadeloupe (French West Indies)"

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Original article Influence of shade on photosynthetic gas exchange of 7 tropical rain-forest species from Guadeloupe (French West Indies) M Ducrey A-Vivaldi, INRA, Laboratoire de Recherches Forestières Méditerranéennes, avenue F-84000 Avignon, France accepted 21 September 1993) 16 November 1992; (Received Summary — Young seedlings from 7 tropical rain-forest species of Guadeloupe (French West In- dies): Dacryodes excelsa, Amanoa caribaea, Richeria grandis, Simaruba amara, Symphonia globu- lifera, Byrsonima coriacea and Podocarpus coriaceus were grown for 1-2 yr in full sunlight or under 4 artificially shaded tunnels transmitting 6, 11, 19 and 54% daylight. Photosynthetic gas exchanges of attached leaves or branches were then studied in the laboratory. Net photosynthesis-light curves were analysed for an average of 4 seedlings per species and per light treatment. Maximum photo- synthesis on a leaf-area basis of sungrown seedlings varied from 3.4 μmol CO m s for Da- 2 -2 -1 cryodes excelsa to 7.9 μmol CO m s for Simaruba amara. For all the species studied and when 2 -2 -1 the measurements were expressed on a leaf-area basis, maximum photosynthesis of sun-grown seedlings was higher than for shade-grown seedlings. The opposite was observed for photosynthe- sis under limited light and for apparent quantum yield. We also observed a decrease in maximum photosynthesis and an increase in apparent quantum yield when specific leaf area increased, ie when the plants were more shaded. The range of variation in photosynthetic response between full sunlight and full shade made it possible to characterize the photosynthetic plasticity of the species. The results were compared with those obtained for other tropical rain-forest species. They are dis- cussed in terms of photosynthetic and morphological plasticity, shade adaptation, and of the species’ place in tropical rain-forest succession. I I forest succession I shade tolerance I net photosyn- photosynthesis tropical rain forest thetic plasticity Résumé — Influence de l’ombrage sur les échanges gazeux photosynthétiques de 7 espèces de la forêt tropicale humide de Guadeloupe (Petites Antilles). De jeunes semis de 7 espèces de la forêt tropicale humide de Guadeloupe (Petites Antilles) : Dacryodes excelsa, Amanoa caribaea, Richeria grandis, Simaruba amara, Symphonia globulifera, Byrsonima coriacea et Podocarpus coria- ceus ont été élevés pendant 1 à 2 ans en pleine lumière et sous 4 tunnels artificiellement ombragés laissant passer 6%, 11%, 19% et 54% de la pleine lumière. À la fin de cette période, on a étudié au laboratoire les échanges gazeux photosynthétiques de feuilles ou de rameaux rattachés aux jeunes plants. Des courbes photosynthèse nette - éclairement ont ainsi été réalisées en moyenne pour 4
plants par espèce et par tunnel. La photosynthèse maximale des plants de pleine lumière varie de 3,4 μmol CO m s pour Dacryodes excelsa à 7,9 μmol CO m s pour Simaruba amara. Pour 2 -2 -1 2 - 2 -1 toutes les espèces étudiées et lorsque les mesures sont rapportées à l’unité de surface foliaire, la photosynthèse maximale des plants de pleine lumière est supérieure à celle des plants d’ombre, tan- dis que l’on observe l’inverse pour la photosynthèse en éclairement limitant et pour le rendement quantique apparent. On note parallèlement une diminution de la photosynthèse maximale et une aug- mentation du rendement quantique apparent lorsque la surface spécifique des feuilles augmente, c’est-à-dire quand les plants sont de plus en plus ombragés. L’amplitude des variations de photosyn- thèse entre la pleine lumière et le plus fort ombrage permet de caractériser la plasticité photosynthéti- que des espèces. Les résultats sont comparés à ceux obtenus avec d’autres espèces forestières de la zone tropicale humide. Ils sont enfin discutés en termes de plasticité morphologique et photosyn- thétique, d’adaptation à l’ombrage, et d’emplacement dans le cycle de succession des espèces dans les forêts tropicales humides. nette / forestière / tolérance à l’ombrage / photosynthèse forêt tropicale humide / succession plasticité photosynthétique foresters in the silvicultural management of INTRODUCTION forest stands. Baker’s (1949) tables of tol- erance for conifers and hardwood species morphological, anatomical, structural, The of North America are an example. ultrastructural, biochemical or photosyn- thetic response of herbaceous species Generally, shade-intolerant forest spe- and shrubs to different light conditions dur- cies are characterized by higher photosyn- ing growth is well known (eg, Boardman, thetic potentials than those of shade- 1977; Björkman, 1981; and Givnish, tolerant species. However, what differen- 1988). In general, the light-saturated rate tiates the species and makes it possible to of photosynthesis, the light compensation classify them in relation to one another, is point, and the light saturation plateau are the possible capacity for intolerant species higher for sun-grown plants than for to tolerate more or less shade, and for tol- shade-grown plants. On the other hand, erant species to survive in high light condi- sun-grown plants have leaves with a lower tions. specific area, and which contain smaller When a species’ forest behavior is em- chloroplasts than shade-grown plants. pirically known, then it is usually possible Most of the responses described above to explain its photosynthetic capacities and also applicable to trees, but the re- are its morphology in terms of shade tolerance sponses of trees may be modified because (see, for example, Tsel’Niker, 1977; Baz- of their variable social status within a forest. and Carlson, 1982; McMillen and zaz For example, sun-shade responses within McClendon, 1983, among others). How- a tree may be different from sun-shade re- empirical knowl- ever, when there is no sponses of seedlings of the same species edge for given species of its ecology or a (Leverenz and Jarvis, 1980). It is also im- its silvicultural behavior, is it possible to de- portant to investigate sun-shade adapta- duce the degree of shade tolerance simply tion at the genotype level. from its photosynthetic capacities and its reactions to experimental variations in light The sun-shade responses can be ex- environment? This question is fundamental pressed by different degrees of shade tol- for a wide variety of forest species which erance, and have long been used by
make up the tropical rain forest and about to answer the following question. Can a which we have almost no silvicultural shade tolerance be predicted by species’ the photosynthetic response of seedlings knowledge. of that species grown under a range of In unmanaged tropical rain forests, the light environments? presence of a species in a particular place at a particular time is almost always condi- tioned by its response to light. Of course, it PLANT MATERIAL also depends on other factors, such as AND STUDY METHOD seed availability, dispersal and germination of these seeds, competition and allelo- pathy processes, or edaphic conditions. Species studied This is the way the species’ succession cy- and seedling growth conditions cle is developed from pioneer species, which require high quantities of light, which seedlings used for the experiment were The are generally shade intolerant, and which sampled from the tropical rain forest of Guade- colonize open space, to species of stable loupe, French West Indies, in the Caribbean Is- adult stands, which are generally more lands. They come from the area called "Débau- shade tolerant when young (Whitmore, chée" (Ducrey, 1986) at an elevation of 250 m. 1978; Rollet, 1983). The opening of these Mean temperatures were 23°C for January and stable stands by natural wind-fallen wood 26°C for July. Mean annual rainfall was more than 3 000 mm. There was a short dry season or partial harvesting, creates gaps whose from January to April, where monthly rainfall size (ie light conditions as well) partially was always greater than 100 mm. determines which species will be able to The 7 species studied were evergreen domi- establish themselves. nant and co-dominant trees from middle and The problem of species succession and late successional cycle of the Guadeloupe’s rain shade tolerance has been posed for the forest. Dacryodes excelsa Vahl, Amanoa cari- baea Kr and Urb, and Podocarpus coriaceus LC Guadeloupe tropical rain forest where we Rich are late successional, shade-tolerant spe- conducted silvicultural studies on 7 com- cies. Simaruba amara Aubl and Richeria grandis mercially interesting species. The objective Vahl mid-successional, shade-intolerant are was to favor natural regeneration of these species. Byrsonima coriacea is present in mid- species (Ducrey and Labbé, 1985). The and late succession, whereas Symphonia globu- study of the seedlings in relation to the in- lifera L, a wet soil specialist, is a late succes- sional species. However the shade reaction of tensity of regeneration fellings gave us pre- these 2 species is not well known. liminary information about light response of The seedlings were generally aged 1 yr, har- the species whose regeneration was in- vested from the forest margin in January 1981, duced by silvicultural treatment (Ducrey and transplanted to 9-I pots filled with soil from and Labbé, 1986). To improve this infor- the upper horizon of the forest floor. The pots mation, we cultivated seedlings from 7 for- were placed under a forest canopy to ensure a est species under semi-controlled light better recovery. After 3 months, the pots were conditions under differently shaded tunnel transferred to tunnel greenhouses, 15 m long greenhouses. In a previous article (Ducrey, and 6 m wide, covered with shade cloth trans- mitting the amount of light desired. The same 1992), we studied the morphological varia- procedure was applied to all species except P tions of the leaf system in relation to coriaceus whose seedlings were all placed in shade. In this paper, we shall examine the the same tunnel in March 1981 and then distrib- photosynthetic response of the seedlings uted to the different tunnels in January 1982, of these 7 species cultivated under 5 differ- and A caribaea which was started 1 yr later in ent shade environments. We shall also try March 1982. The seedlings were regularly wa-
tered twice a week. No fertilizer used dur- ential gas analyser of carbon dioxide (ADC mod- was ing the experiment. el) which measured the difference in CO con- 2 centration between the reference circuit and the The seedlings were separated into 5 treat- measured circuit. The temperature was set be- ments: 4 treatments under plastic tunnels and 1 tween 25 and 27°C using a water cooling sys- open air, full sunlight treatment. The 4 tunnel tem where the measurement chamber was sub- shelters were covered with reinforced transpar- merged in a tank containing cooled water. ent PVC to protect against rainfall. Three of Relative humidity of the air was maintained be- them were shaded with different black neutral tween 70 and 90% by bubbling air into a water shade screens in order to obtain various shade flask maintained at the temperature of the de- conditions. Finally, global radiation measure- sired dew point. ments with Li-Cor, Li 200 pyranometers indi- cates 6.4% light under tunnel I, 11.4% light un- Lighting was achieved using a mobile stand der tunnel II, 18.8% light under tunnel III, and of tungsten-halogen quartz lamps with a unit 54.3% light under tunnel IV. power of 1 000 W. Photosynthetic active radia- tion was measured with a Li-Cor, LI 190 quan- Table I shows climatic data under tunnel tum sensor. Four light levels were used: 28 and shelters. These were opened and oriented in 56 μmol m s for low light; 368 and 632 μmol -2 -1 the direction of prevailing winds. The tempera- -2 -1 m s for saturating light. A few measurements ture and humidity of the air under the tunnels were also taken at 924 μmol m s but the re- -2 -1 , the same as those in the open-air treat- were sults were always less than or equal to those at (meteorological data measured with a ment 632 μmol m s We thus considered that satu- -2 -1 . weather station), except for tunnel IV whose ration was reached between 368 and 632 μmol maximum temperatures were slightly higher -2 -1 m s and we did not use the data for 924 , than in the others. In fact, the shade under this μmol m s Gas exchange measurements -2 -1 . tunnel was created using only a reinforced trans- were made first in darkness to calculated dark parent plastic cover which caused a more signifi- respiration and then with increasing light levels. cant warming effect. Because of only small cli- matic differences between experimental The area and dry weight of the leaves stud- treatments and additional watering, we can con- ied were also calculated. This made it possible sider that light is the major variable between the to calculate photosynthesis per unit of leaf area 5 treatments. and per unit of leaf dry matter, and to determine the specific leaf area (ratio between leaf area and leaf dry weight) of the leaves studied (table III). Measurements of net photosynthesis Dark respiration and photosynthesis in low light made it possible to determine the initial slope of the net photosynthesis-light curves Photosynthesis measurements took place from which is called apparent quantum yield and the end of October to the end of December which approximates to the quantum yield of the 1982. The seedlings were kept under the experi- leaf (number of moles of CO assimilated per 2 mental light conditions for close to 2 yr (except mole of photons absorbed by the leaf) except that for A caribaea and P coriaceus which were kept only incident photon flux density was measured. for only 1 yr) and all the leaves measured were Light-saturated net photosynthesis was then initiated and grown under the treatment condi- calculated as an average of photosynthesis val- tions. These leaves could be considered as be- ues recorded at 368 and 632 μmol m s In -2 -1 . ing completely acclimated to the experimental the same way, light-limited net photosynthesis is light conditions. Measurements were made on an average of photosynthesis values recorded fully developed leaves. The mean size of the at 28 and 56 μmol m s -2 -1 . seedlings used in photosynthesis measure- ments is shown in table II. An average of 4 seedlings per tunnel and per The measurements of net photosynthesis species were used, representing a total of 147 carried out in the laboratory on attached plants and 147 net photosynthesis-light curves. were leaves or branches placed in a ventilated cham- The 4 variables defining the 147 net photosyn- ber, perpendicular to the light source. The thesis-light curves carried out for this study were measurement of carbon dioxide exchange was analysed by an analysis of variance with 1 fac- made in an open system using an infrared differ- tor, Tunnel, for each species. Differences be-
combine the net photo- of these results, were set out with a Duncan’s test tween tunnels we of multiple mean comparisons. Relationships for each species in synthesis-light curves between these 4 variables and relative light in- dense shade (tunnel I, 6% relative light in- tensity were analysed by linear regression, spe- tensity) and full sunlight (tunnel V, 100% cies by species, on raw data. RLI) in figure 1. RESULTS Light-saturated net photosynthesis The results shown in table IV represent For plants grown in full sunlight, light- data recorded per unit of leaf area; those saturated photosynthesis recorded per unit in table V show data recorded per unit of of leaf area was the highest for S amara dry matter. To facilitate the interpretation
(7.9 μmol m s and the lowest for D ex- -2 -1 ) dry matter units, the species ranking was celsa (3.4 μmol m s Photosynthesis -2 -1 ). approximately the same. The small recorded per unit of dry matter was then amount of change was due to small differ- 65 nmol g s for S amara and 35 nmol -1 -1 ences in specific leaf area between spe- cies, for plants grown in full sunlight. -1 -1 g s for D excelsa. The other species had intermediate values. Whether photo- For plants grown in shady conditions, synthesis was recorded per leaf area or light-saturated photosynthesis recorded
lower for plants grown in full sunlight than per unit of leaf showed general a area for plants grown in shady conditions. All trend, decreasing from light shade (tunnel species considered together, apparent IV, 54% RLI) to heavy shade (tunnel I, 6% quantum yield was slightly, but statistically RLI). Some species, like S amara, reacted greater for shaded plants (47-49 mmol strongly than others to changes in more ) -1 mol than for sun-grown plants (42 mmol light regime, as shown in figure 1. An ). -1 mol opposite trend was found when photosyn- thesis was recorded in dry matter units. Photosynthesis is then higher for plants Dark respiration under heavy shade (tunnels I, II and III, 6-19% RLI) than for plants under light shade (tunnel IV, 54% RLI) or in full sun- Leaf dark respiration was very low for A light. caribaea and very high for P coriaceus, R grandis and S amara, whether it was expressed on dry-weight or leaf-area ba- Light-limited net photosynthesis Compared with apparent quantum sis. yield, these data seem to indicate that species with a high apparent quantum For plants grown in full sunlight, light- yield also had a high dark respiration and limited photosynthesis on a leaf area basis vice versa. Only P coriaceus seems to be was the highest for S globulifera (1.8 μmol an exception and had a high dark respira- -2 -1 m s and the lowest for D excelsa ) tion along with a low apparent quantum (0.8 μmol m s Photosynthesis record- -2 -1 ). yield. All species considered together, res- ed per unit of dry matter was then 23 nmol piration was lowest in tunnels II and III, g s for S globulifera and 9 nmol g s -1 -1 -1 -1 and highest in strong shade and full sun- for D excelsa and P coriaceus. The other light. species had intermediate values. For under different shade plants grown treatments, light-limited photosynthesis Influence of growth conditions on leaf-area basis decreased from deep and leaf characteristics a shade (tunnel I, 6% RLI) to light shade (tunnel IV, 54% RLI), the lowest values be- It was interesting to relate the results ob- ing encountered in full sunlight. At a spe- tained in the different tunnels to light condi- cies level, this trend was not always true tions and specific leaf area. Figure 2 because of high data variability. This trend shows that when all the species are con- appeared clearly for most of the species sidered together, maximum photosynthesis when photosynthesis was recorded per per leaf area unit increased with relative unit of dry matter. light intensity during growth, at first rapidly until the relative light intensity was near 20% (tunnel III), then much more slowly Apparent quantum yield (fig 2a). On the other hand, it decreased regularly when specific leaf area increased (fig 2b), ie with increasing shade. For plants grown in full sunlight, apparent quantum yield was the highest for S amara Apparent quantum yield decreased with (58 mmol mol and R grandis (54 mmol ) -1 relative light intensity (fig 2c) and in- ) -1 mol and the lowest for D excelsa (23 creased with specific leaf area (fig 2d). Its ). -1 mol mmol These values variation was the reverse of that found for slightly were
to specific leaf area, species maximum net photosynthesis. This phe- According be ranked from the most plastic to the nomenon has frequently been observed may least plastic species: R grandis, S amara, when comparing shade and sun pheno- B coriacea, D excelsa, A caribaea, S glob- types. ulifera and P coriaceus. According to light- regressions to explain specific Linear saturated photosynthesis, S amara was light-saturated photosynthesis, leaf area, found to be the most plastic species. It was light-limited photosynthesis and apparent followed, in decreasing order, by R gran- quantum yield as a function of relative light dis, B coriacea and P coriaceus. D excelsa intensity, were calculated for each species and A caribaea both had "a" coefficients (table VI). Most of the regressions were not significantly different from zero, where- statistically significant at a 5% level, except as S globulifera reacted negatively to in- for apparent quantum yield. The "a" creasing relative light intensity. For each coefficient in the regression equation ex- species, light-limited photosynthesis and presses, for a given trait, the species plas- apparent quantum yield decreased with in- ticity in reaction to light conditions during creasing light intensity. growth.
close to 5 μmol CO m s for maximum 2 -2 -1 DISCUSSION AND CONCLUSION net photosynthesis and 0.6 μmol CO m 2 -2 -1 s for dark respiration. Large differences Comparison between species in shade tolerance can be seen between these species, but the knowledge of their For the 7 species studied in Guadeloupe, photosynthetic potential is not sufficient to maximum net photosynthesis in full sun- rank them according to an increasing order light was between 3.4 μmol m s for D -2 -1 of shade tolerance. The understory spe- excelsa and 7.9 μmol m s for S amara. -2 -1 cies have a photosynthesis close to 2 μmol The corresponding respiration values var- 2 -2 -1 CO m s and a respiration close to 0.2 ied from 0.15 to 0.64 μmol m s de- -2 -1 μmol CO m s 2 -2 -1 . pending on the species. Our results are These results give a good idea of the compared (table VII) with the results of photosynthetic potential of tropical rain- others studies including those by Stephens forest species. They are, in fact, very close and Waggoner (1970), Bazzaz and Pickett to those for temperate forest species found (1980), Koyama (1981), Oberbauer and by Bazzaz (1979), who gives photosyn- Strain (1984), Langenheim et al (1984), thetic potentials of 10.0 for species at the and Thompson et al (1988). beginning of the succession, 5.7 for spe- Pioneer trees in the early successional cies at the end of succession, and 2.2 for or young secondary formations gen- stages understory species. erally have a high photosynthetic potential (14 μmol CO m s along with a high 2 -2 -1 ) dark respiration (0.8 μmol CO m s 2 -2 -1 ). Comparison of sun Stable forest formations in the late succes- and shade phenotypes sional species stages are composed of 3 main layers: an upper layer including For the 7 species studied, apparent emergent and dominant trees; a middle quantum yield was higher for shade-grown layer composed of average-sized trees plants (shade phenotypes) than for which completely close the forest canopy; sun-grown plants (sun phenotypes). On and a lower layer composed of understory the other hand, light-saturated photosyn- species. thesis on a leaf-area basis was higher for Among the emergent trees both "sun" phenotypes than for shade pheno- sun which shade intolerant and species are types, except for A caribaea and S globulif- "shade" species which are more or less tol- era. erant to shade can be found. Sun species have an almost identical response to that Similar results were reported by Logan of pioneer species (photosynthesis: 11 (1970) for Betula alleghaniensis, by μmol CO m s and dark respiration: 1.0 2 -2 -1 Tsel’Niker (1977) for 5 forest species, by μmol CO m s 2 -2 -1 ). An analogy can be Duba and Carpenter (1980) for Platanus made between these 2 groups as the occidentalis, by Bazzaz and Carlson emergent sun species appear very early in (1982) for 12 herbaceous and shrub spe- the first successional stages as do the pio- cies and by Nygren and Kellomaki (1983) neer species, but they have a much longer for 10 forest species. All the species stud- life than the latter which is why they can be ied by these authors belong equally to the found in the late successional stages. early and late successional stages and thus both shade-tolerant and shade- The results for shade species from the upper layer and from the middle layer are intolerant species can be found.
The commonly accepted explanation for than that of sun phenotypes. Similar re- er these results is that shade and sun pheno- sults were also found by Gatherum et al types are well adapted to the light environ- (1963) for 3 different forest species. Logan ment in which they grow and that the light and Krotkov (1969) interpreted these re- level at which photosynthesis reaches its sults by saying that when plants of this saturation plateau corresponds to the light type photosynthesize under the same light conditions most commonly found by the conditions, plants grown under low light plant in its natural environment (Tsel’Niker, use light more efficiently than those grown in full sunlight. 1977). Under these conditions, shade phenotypes have higher quantum yield The 2 main types of results for shade and lower light-saturated photosynthesis. and sun phenotypes are contradictory and For A caribaea, found many references could be quoted for each effect of we no light growth conditions on light-saturated point of view. Logan and Krotkov (1969) photosynthesis, whereas light-saturated tried to provide an explanation. They hy- photosynthesis of S globulifera was higher pothesized that the photosynthetic mecha- for shade-grown plants than for sun-grown nisms of tolerant species are better adapt- plants. Similar results have also been ed to low rather to high light habitats, and found by various authors. For Tilia ameri- conversely, that the photosynthetic mecha- cana, Bazzaz and Carlson (1982) found nisms of intolerant species are better that sun and shade phenotypes had identi- adapted to high rather than to low light cal rates of photosynthesis. For Acer sac- habitats. This theory involves the degree of charum, Logan and Krotkov (1969), and adaptation to shade and is not entirely con- Bazzaz and Carlson (1982) found that pho- vincing as both types of response can be found in tolerant and intolerant species. tosynthesis of shade phenotypes was high-
When we expressed photosynthesis on plant sample from the same experiment dry leaf matter basis, it was found that, for (Ducrey, 1992). all species, the highest values correspond- From the regressions between light- ed to shade phenotypes and the lowest to saturated photosynthesis and relative light sun phenotypes (see table VI). Photosyn- intensity, an index of photosynthetic plas- thesis per unit dry weight can be consid- ticity may be defined. S amara appears as ered to be the product of the specific leaf the most plastic species. The following are area by photosynthesis per unit leaf area. then found in decreasing order: R grandis, For the species studied, photosynthesis B coriacea, P coriaceus, D excelsa and A per unit leaf area decreased with shade caribaea. S globulifera reacted negatively while specific leaf area increased, and the to increasing light intensity. final result, as we have seen, was an in- There is a good agreement between the crease with shade of photosynthesis per different indexes of plasticity, the pre- unit dry weight. This result depends on the sumed degree of shade tolerance of degree of variation between shade and Guadeloupe species and their place in the sun for the 2 parameters studied. Thus, species’ succession cycle in tropical rain any result is possible and would depend forests. Simaruba amara and Richeria on the morphological and photosynthetic grandis are the most plastic species from a plasticity of the species studied. morphological and photosynthetic point of view. They are early successional species, but not really pioneer species, and were Photosynthetic plasticity considered as light-intolerant species (Du- and shade adaptation crey and Labbé, 1986). Byrsonima coria- cea is also a plastic species. This makes it Bazzaz and Carlson (1982) introduced the possible to rank this species among shade notion of photosynthetic flexibility (or plas- intolerant species even though little was ticity) to interpret the range of variation, previously known about its forest behavior. from dense shade to full sunlight, in The 3 species Podocarpus coriaceus, Da- parameters defining the photosynthetic ac- cryodes excelsa and Amanoa caribaea had tivity of a given species. They concluded in low morphological and photosynthetic plas- their study that photosynthetic flexibility ticity indexes. They are more or less shade was higher for early pioneer successional tolerant and are late succession species. A species, average for intermediate species special emphasis should be made on Sym- and lowest for late successional species. phonia globulifera, a species with very low plasticity, and whose light-saturated photo- The "a" coefficients from table VII may synthesis decreased with increasing relative be considered as indicators of species light intensity. This species should be a plasticity. From the regressions between strict "shade species", but it is also a wet specific leaf area and relative light intensi- soil specialist, so it may be a dominant spe- ty, an index of morphological plasticity cies in the late succession stages. may be defined. According to this index, R grandis and S amara are the 2 most plas- This work has made it possible to gain a tic species, immediately followed by B cori- basic knowledge about the photosynthetic acea; D excelsa and A caribaea are less potentials of the main commercially inter- plastic; and S globulifera and P coriaceus esting forest species from the Guadeloupe are the least plastic species. These results tropical rain forest. It has also character- agree with those obtained on a greater ized the shade and sun phenotypes of
Ducrey M (1992) Variation in leaf morphology these species from the point of view of and branching pattern of some tropical rain their photosynthetic activity. However, forest species from Guadeloupe (French studying only photosynthetic activity West Indies) under semi-controlled light con- to be insufficient to determine the seems ditions. Ann Sci For 49 (6), 553-570 degree of shade tolerance. It is neverthe- Ducrey M, Labbé P (1985) Étude de la régéné- less a useful element which, when added ration naturelle contrôlée en forêt tropicale to other elements concerning the morpho- humide de Guadeloupe. I. Revue bibliogra- and biochemical of the logical adaptation phique, milieu naturel et élaboration d’un pro- tocole expérimental. Ann Sci For 42 (3), 297- leaf apparatus, growth, and biomass pro- 322 duction, will make it possible to increase P (1986) Étude de la régéné- Ducrey M, Labbé of the be- knowledge ecophysiological our ration naturelle contrôlée en forêt tropicale havior of these species. humide de Guadeloupe. II. Installation et croissance des semis après les coupes d’en- semencement. Ann Sci For 43 (3), 299-326 REFERENCES Gatherum GE, McComb AL, Loomis WE (1963) Effects of light and soil moisture on forest tree seedling establishment. Iowa Agric Exp A revised tolerance table. J For Baker FS (1949) Stn Res Bull 513, 777-792 47, 179-181 Givnish TJ (1988) Adaptation to sun and shade: Bazzaz FA (1979) The physiological ecology of a whole plant perspective. Aust J Plant Phys- plant succession. Ann Rev Ecol Syst 10, iol 15, 63-92 351-377 H (1981) Photosynthetic rates in low- Koyama Bazzaz FA, Carlson RW (1982) Photosynthetic land rain forest trees of peninsular Malaysia. acclimation to variability in the light environ- Jpn J Ecol 31, 361-369 ment of early and late successional plants. Langenheim JH, Osmond CB, Brooks A, Ferrar Oecologia (Berl) 54, 313-316 PJ (1984) Photosynthetic responses to light Bazzaz FA, Pickett STA (1980) Physiological in seedlings of selected Amazonian and Aus- ecology of tropical succession: A compara- tralian rain-forest tree species. Oecologia tive review. Ann Rev Ecol Syst 11, 287-310 (Berl) 63, 215-224 Björkman O (1981) Responses to different quan- Leverenz JW, Jarvis PG (1980) Photosynthesis tum flux densities. In: Encyclopedia of Plant in Sitka Spruce (Picea sitchensis (Bong) Carr) Physiology, Physiological Plant Ecology (OL X. Acclimation to quantum flux densities within Lange, PS Nobel, CB Osmond, H Ziegler, and between trees. J Appl Ecol 17, 697-708 eds) Vol 12A. Springer Verlag, Berlin, 57-102 (1967) Shade tolerance in tree seed- Loach K Björkman O, Ludlow MM, Morrow PA (1972) lings. I. Leaf photosynthesis and respiration Photosynthetic performance of 2 rain forest in plants raised under artificial shade. New species in their native habitat and analysis of Phytol 66, 607-621 their gas exchange. Carnegie Inst Washing- Logan KT (1970) Adaptation of the photosyn- ton Year Book 71, 94-102 thetic apparatus of sun- and shade-grown Boardman NK (1977) Comparative photosynthe- yellow birch (Betula alleghaniensis Britt). Can sis of sun and shade plants. Ann Rev Plant J Bot 48 (9), 1681-1688 Physiol 28, 355-377 Logan KT, Krotkov G (1969) Adaptations to the SE, Carpenter SB (1980) Effect of shade Duba photosynthetic mechanism of sugar maple the growth, leaf morphology and photo- (Acer saccharum) seedlings grown in various on synthetic capacity of an american sycamore light intensities. Physiol Plant 22, 104-116 clone. Castanea 45 (4), 219-227 Lugo A (1970) Photosynthetic studies on 4 spe- Ducrey M (1986) Croissance juvénile de cies of rain forest seedlings. In: A tropical introduites dans rain forest (HT Odum, RF Pigeon, eds) US quelques espèces I’arboretum de Débauchée (Guadeloupe). Atomic Energy Commission, NTSI, Spring- Rev For Fr XXXVIII (5), 451-456 field, VA, USA, I, 7, 81-102
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