Identification and Distribution of C3 and C4 Grasses in Open and Shaded Habitats in Sao Paulo State, Brazil1 Carlos Augusto Klink and Carlos Alfredo Joly Departamento de Botanica-Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109-Campinas-SP-Brazil- 13.100 ABSTRACT The photosynthetic pathway of grasses collected in several vegetation formations in Sao Paulo State, Brazil, was identified by leaf anatomy. Of the 78 species collected, 48 sun species and seven shade species possessed the C4 pathway. Twenty-three species possessed the C3 pathway, of which three were sun species and 20 were shade species. This result indicates that the C4 species are more abundant in open habitats and C3 species in shaded habitats. The data also show the taxonomic distribution of the photosynthetic pathways. All genera of the collected species are exclusively C3 or C4, except Panicum which has both C3 and C4 species. RESUMO A via do metabolismo fotossint6tico de especies de gramineas coletadas em diversas formaco~es vegetais do Estado de Sao Paulo, Brasil, foi identificada pela anatomia foliar. Das 78 especies coletadas, 55 foram identificadas como C4, sendo 48 de sol e sete de sombra; e 23 como C3, sendo tres de sol e 20 de sombra. Os idados indicam que plantas C4 ocupam principalmente os ambientes abertos enquanto que as C3, os ambientes sombreados. Os dados mostram tambem a distribuica~o taxonomica das vias fotossinteticas. Todos os generos das especies coletadas sao exclusivamente C3 ou C4, a exceqao de Panicum, que apresenta tanto especies C3 quanto C4. SINCE THE DISCOVERY OF THE DIFFERENT TYPES of photosyn- thetic pathways in higher plants, it has been shown that C3 and C4 species can differ in anatomical, biochemical, physiological, and ecological aspects (Welkie & Caldwell 1970, Edwards & Walker 1983, Pearcy & Ehleringer 1984). Teeri and Stowe (1976) have shown the influence of climate variables on the distribution of C4 grasses in North America, and since then various authors have been studying the relationship between the distribution of C4 species and climatic patterns: Chazdon (1978) in Costa Rica, Meinzer (1978) in Central America, Rundel (1980) in Hawaii, Stowe and Teeri (1978) in North America, Vogel et al. (1978) in South Africa, and Hattersley (1983) in Australia. Generally, these authors have noted that C4 species usually occupy hot and arid habitats, supporting the hypothesis that C4 photosynthetic metabolism is spe- cifically an adaptation to these environments (Laetsch 1974). However, some differences were observed among the different groups of plants studied. For example, Teeri and Stone (1976) found that the highest minimum temper- ature during growth was the climatic variable most cor- related with the distribution of C4 grasses in North Amer- ica while water deficits of the soil were most correlated with tthe distribution of C4 Dycotyledoneae in the same region (Stowe & Teeri 1978). Moreover, Hattersley (1983) concluded that no relationship has been established be- tween irradiance and geographic distribution of the species. He argued that the available irradiance data are inappro- priate to this kind of analysis because they "disregard" the existence of a vegetation canopy. This observation considers the fact that beyond the action of climatic vari- ables in a geographic level, there is the action of local variables in the distribution of C3 and C4 species. Ac- cording to Teeri (1979) the macroscale climatic variables provide only gross approximations of the influence of the climate on a plant tissue during its growth, and on a microclimatic scale, other variables are probably important in determining the performance of C3 and C4 species. Our objective was to identify by leaf anatomy the photosynthetic pathway of grasses from different vegeta- tion formations of the State of Sao Paulo, Brazil, and correlate the distribution of these species with the local conditions of irradiance. MATERIAL AND METHODS The vegetation formations which were exposed directly to the sun all day were classified as open habitats and those which were not exposed directly to the sun (under a vege- tation canopy) were classified as shaded.Question 11) Give the main aim of the article. (5)2) Name five C3 and C4 grasses in an upland forest that were used in this article (10)3) How many C4 plant species were collected in a closed vegetation formation, coastal rain forest and upland forest? (10)Question 21) In the materials and methods, how were C3 and C4 plants classified? (5)2) Explain which methods were used to observe the leaf anatomy. (5)Question 3Based on the article below, please explain why Klink and Joly (1989) in their results concluded that the C4 species are more abundant in open habitats and C3 speciesin shaded habitats? (15)Question 4Based on the discussion in the article, distinguish C3 and C4 plants in a table format.

Question

Identification and Distribution of C3 and C4 Grasses in Open and Shaded Habitats in Sao Paulo State, Brazil1 Carlos Augusto Klink and Carlos Alfredo Joly Departamento de Botanica-Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109-Campinas-SP-Brazil- 13.100 ABSTRACT The photosynthetic pathway of grasses collected in several vegetation formations in Sao Paulo State, Brazil, was identified by leaf anatomy. Of the 78 species collected, 48 sun species and seven shade species possessed the C4 pathway. Twenty-three species possessed the C3 pathway, of which three were sun species and 20 were shade species. This result indicates that the C4 species are more abundant in open habitats and C3 species in shaded habitats. The data also show the taxonomic distribution of the photosynthetic pathways. All genera of the collected species are exclusively C3 or C4, except Panicum which has both C3 and C4 species. RESUMO A via do metabolismo fotossint6tico de especies de gramineas coletadas em diversas formaco~es vegetais do Estado de Sao Paulo, Brasil, foi identificada pela anatomia foliar. Das 78 especies coletadas, 55 foram identificadas como C4, sendo 48 de sol e sete de sombra; e 23 como C3, sendo tres de sol e 20 de sombra. Os idados indicam que plantas C4 ocupam principalmente os ambientes abertos enquanto que as C3, os ambientes sombreados. Os dados mostram tambem a distribuica~o taxonomica das vias fotossinteticas. Todos os generos das especies coletadas sao exclusivamente C3 ou C4, a exceqao de Panicum, que apresenta tanto especies C3 quanto C4. SINCE THE DISCOVERY OF THE DIFFERENT TYPES of photosyn- thetic pathways in higher plants, it has been shown that C3 and C4 species can differ in anatomical, biochemical, physiological, and ecological aspects (Welkie & Caldwell 1970, Edwards & Walker 1983, Pearcy & Ehleringer 1984). Teeri and Stowe (1976) have shown the influence of climate variables on the distribution of C4 grasses in North America, and since then various authors have been studying the relationship between the distribution of C4 species and climatic patterns: Chazdon (1978) in Costa Rica, Meinzer (1978) in Central America, Rundel (1980) in Hawaii, Stowe and Teeri (1978) in North America, Vogel et al. (1978) in South Africa, and Hattersley (1983) in Australia. Generally, these authors have noted that C4 species usually occupy hot and arid habitats, supporting the hypothesis that C4 photosynthetic metabolism is spe- cifically an adaptation to these environments (Laetsch 1974). However, some differences were observed among the different groups of plants studied. For example, Teeri and Stone (1976) found that the highest minimum temper- ature during growth was the climatic variable most cor- related with the distribution of C4 grasses in North Amer- ica while water deficits of the soil were most correlated with tthe distribution of C4 Dycotyledoneae in the same region (Stowe & Teeri 1978). Moreover, Hattersley (1983) concluded that no relationship has been established be- tween irradiance and geographic distribution of the species. He argued that the available irradiance data are inappro- priate to this kind of analysis because they &#34;disregard&#34; the existence of a vegetation canopy. This observation considers the fact that beyond the action of climatic vari- ables in a geographic level, there is the action of local variables in the distribution of C3 and C4 species. Ac- cording to Teeri (1979) the macroscale climatic variables provide only gross approximations of the influence of the climate on a plant tissue during its growth, and on a microclimatic scale, other variables are probably important in determining the performance of C3 and C4 species. Our objective was to identify by leaf anatomy the photosynthetic pathway of grasses from different vegeta- tion formations of the State of Sao Paulo, Brazil, and correlate the distribution of these species with the local conditions of irradiance. MATERIAL AND METHODS The vegetation formations which were exposed directly to the sun all day were classified as open habitats and those which were not exposed directly to the sun (under a vege- tation canopy) were classified as shaded.Question 11) Give the main aim of the article. (5)2) Name five C3 and C4 grasses in an upland forest that were used in this article (10)3) How many C4 plant species were collected in a closed vegetation formation, coastal rain forest and upland forest? (10)Question 21) In the materials and methods, how were C3 and C4 plants classified? (5)2) Explain which methods were used to observe the leaf anatomy. (5)Question 3Based on the article below, please explain why Klink and Joly (1989) in their results concluded that the C4 species are more abundant in open habitats and C3 speciesin shaded habitats? (15)Question 4Based on the discussion in the article, distinguish C3 and C4 plants in a table format.

Accepted Answer

The photosynthetic pathway of grasses collected in several vegetation formations in Sao Paulo…