IAWA Journal, Vol. 18 (1),1997: 37-51

WOOD STRUCTURE OF ALPATACO AND P. ARGENTINA GROWING UNDER DIFFERENT EDAPHIC CONDITIONS by

Pablo E. Villagra 1 & Fidel A. Roig J unent 2

SUMMARY

Prosopis alpataco Phil. and P. argentina Burk. are growing under different ecological conditions within the Monte Desert, Argentina. Both species have similar wood structure: semi-ring-porosity, vessels with a bimodal diameter distribution, short vessel elements, paratracheal confluent axial parenchyma, libriform fibres and homocellular rays. Prosopis alpataco has wider vessels and a greater proportion of solitary vessels than P. argentina which has narrower vessels, mainly in clusters, and a larger number of vessels per mm2. The wood structure of P. argentina suggests a safer, but less efficient, water-conducting system than that of P. alpataco. This could be related to P. argentina's tolerance to high water stress, as this species occurs mostly in sand dunes. Instead P. alpataco is a phreatophyte, getting a regular water supply. Key words: Ecological wood anatomy, Prosopis, Monte Desert, Argen• tina.

INTRODUCTION

The genus Prosopis consists of 44 species distributed in tropical and subtropical deserts of Southwest Asia, Africa and predominantly America, from western North America to Patagonia (Burkart 1976; Simpson & Solbrig 1977). The genus includes , shrubs and, rarely, sub-shrubs. Thirty-one species are indigenous to South America, 28 occur in Argentina (Burkart 1976). Prosopis species are important in desert ecosystems (Simpson & Solbrig 1977). Since pre-Colombian times Prosopis has played an important role in the lives of people inhabiting these arid regions as it provides shade, firewood, timber and food, and forage for domestic herbivores (D' Antoni & Solbrig 1977). The great morphological diversity of the South American species and the pattern of flavonoid chemistry (Carman 1973) suggest that the genus Prosopis had a centre of radiation in the Argentinian-Paraguayan Chaco, and from there, by speciation, may have spread over more xeric territories toward the south and west (Burkart 1976; Burkart & Simpsom 1977; Roig 1993). Probably, this expansion involved several adaptive processes such as the change from arboreal to shrubby bioforms, the reduction of leaf surface, and the modification of the wood anatomical structure of stems and roots.

1) Instituto Argentino de Investigaciones de las Zonas Aridas (IADIZA). CC. 507, CPo 5500 Mendoza, Argentina. 2) Laboratorio de Dendrocronologia, IANIGLA-CRICYT, Cc. 330, CPo 5500 Mendoza, Argen• tina.

Downloaded from Brill.com10/05/2021 06:27:52AM via free access 38 IAWA Journal, Vol. 18 (1), 1997

300

z <:

~ u o

300 U - ~

- argentina U

<: argentinaargentina ~ <: ~ ,(q V <)

V

40° "'- " ~ ~ y "'- ~

Prosopis argentina Burk. Prosopis alpataco Phil.

• = Asuncion .6. = Telteca Reserve

Fig. 1. Geographic distribution of Prosopis argentina and P. alpataco and sampled sites.

Downloaded from Brill.com10/05/2021 06:27:52AM via free access Villagra & Roig - Edaphic factors and wood structure of Prosopis 39

Good examples of species adapted to extreme environmental conditions are Prosopis argentina Burk. and Prosopis alpataco Phil., which are shrubby species distributed mainly in the Monte Phytogeographical Province (Cabrera 1976; Roig 1993). The Monte region stretches slantwise in the Argentinian territory from 24° 35' S to 44° 20' S; and from 69° 50' W to 62° 54' W. Climate is semiarid to arid. The average annual rainfall is < 200 mm/year. The annual maximum and minimum temperatures are 45°C and -10°C, respectively. Rainfall is mostly torrential and occurs primarily in summer. Mark• ed seasonality indicates a distinctly continental climate (Morello 1958). Prosopis argentina has a smaller geographical distribution than P. alpataco (Fig. 1), and is found mostly in the northern Monte, although it reaches the Chaco Phyto• geographical Region. It is considered to be a megatherrnic species whose southern distribution is defined by the 16°C minimum summer isotherm and the 48 °C absolute maximum isotherm (Roig et al. 1992). Prosopis alpataco has a more austral distribu• tion within the Monte, and extends to Patagonia, Pampa and Chaco. In the Monte, P. argentina and P. alpataco occupy areas with very different soil characteristics. Prosopis argentina occurs primarily in mobile and semifixed sand dunes (Burkart 1976; Roig 1993; Dalmasso et al. 1988), while P. alpataco prefers areas with clayish soils and sporadic flood events (Roig 1987, 1993). Prosopis argentina is regarded as a typical xerophyte capable of withstanding con• ditions of extreme drought (Burkart 1976). It has more xeromorphic features than P. alpataco, showing leaf reduction, thick leaf cuticles, lower stomatal density and higher leaf hair density (Vilela, pers. comm.), and photosynthesizing green stems. This species reaches a height of 2.5 m and a crown diameter of 10-15 m (Fig. 2a). Prosopis alpataco is a phreatophyte (a species with long taproots that allows it to reach under• ground water) (Roig 1987). This species has more mesomorphic leaf features than P. argentina, and shows no green stems. The P. alpataco's community appears as patches of shrubby vegetation within areas bare of vegetation. This species reaches a height of 4 m and a crown diameter of 10-15 m (Fig. 3a). The occurrence of these species in different substrates (sandy or clayey) could be related in part to special characteristics of their wood structures. Several authors (Fahn 1964; Metcalfe & Chalk 1983; Carlquist & Hoekman 1985) consider that the anatomi• cal and morphological wood structure could be an important indicator of ecological adaptation in , especially in xerophytes. Nevertheless, an efficient water trans• port system is just one of the alternative ways for a to survive in arid regions. When evaluating the degree of adaptation of a species to its environment, its leaf struc• ture, phenology, root system and photosynthesis should also be considered (Baas & Carlquist 1985). The presence of some adaptations, e.g., deep roots, may allow wood of arid regions to have mesomorphic features (Lindorf 1994). Several authors have studied the wood structure of Prosopis species (Tortorelli 1956; Villalba 1985; Gimenez de Bolzon 1993; Castro 1994), including P. argentina and P. alpataco (Castro 1994). These studies indicate that wood structure in the genus Prosopis is relatively uniform (Table 1). However, the relationship of wood structure to soil conditions was not emphasized in these studies.

Downloaded from Brill.com10/05/2021 06:27:52AM via free access 40 IAWA Journal, Vol. 18 (1), 1997

Table 1. Selected wood anatomical features of Prosopis argentina and P. alpataco and other relevant species of the Monte Desert.

P. alpataco P. argentina P. flexuosa 1 P. chilensis 2 P. strombulifera 2 Bioform: shrub tree sub-shrub Vessels Porosity semi- semi- semi- semi-ring to diffuse-porous ring-porous ring-porous ring-porous circular porous Pores per sq.mm 52 (14-80) 142 (69-230) 30 (13-47) 94 (20-256) 193 (120-304) Diameter (j.lIIl) 58 (10-152) 40 (8-127) 80 (20-140) 94 (27-200) 104 (10-191) Length (flm) 72-248 76-294 140 (100-170) 172 (80-243) 136 (64-216) Rays Height (j.lIIl) 282 (56-856) 438 (51-1000) 300 (150-450) Rayspermm 8.5 7.6 5 48 permm2 90 per mm2

Fibres Length (j.lIIl) 752 (404-1015) 523 (279-838) 920 1006 (648-1680) 667 (391-1606) 1) Data from Villalba 1985; 2) Data from Castro 1994.

The goals of this paper were to determine the differences between the wood anatomy of P. argentina and P. alpataco, and to analyze their possible relations with specific edaphic conditions.

MATERIALS AND METHODS

Five wood samples of each species were collected in the desert NE of Mendoza Prov• ince (Argentina) (Fig. 1). Samples of 3-8 cm in diameter were taken from the main stem of living shrubs, 20-30 cm above the ground. The soil characteristics of the sampled sites are shown in Table 2.

Table 2. Edaphic characteristics (0.00-0.30 cm deep) of the sites where wood samples were collected. Values are the average of two soil samples per site.

Provenances Asuncion Telteca Reserve Scrub type Prosopis alpataco Prosopis argentina Texture clayish sandy Clay % 4.52 0.36 Silt % 1.42 1.12 Fine sand % 56.55 64.70 Coarse sand % 37.52 33.67 C. E. A. (uSm) 2551 337 pH 7.27 7.20 Ca++ (mell) 29.80 2.50 Mg++ (me/I) 2.20 0.30 Na+ (me/l) 2.35 0.63 R.A. S. 0.58 0.44 Organic matter (%) 1.25 0.39

Downloaded from Brill.com10/05/2021 06:27:52AM via free access Villagra & Roig - Edaphic factors and wood structure of Prosopis 41

Fig. 2. Prosopis argentina. - a: P. argentina individuals growing in sand dunes (Teiteca Re• serve). - b: Cross section, growth ring with vessels mainly grouped (bar = lOO filll). - c: Tangential section, homocellular rays, uni-multiseriate (bar = 100 filll). - d: Radial section, procumbent ray cells and prismatic crystal in chambered axial parenchyma cells (bar = 10 filll).

Downloaded from Brill.com10/05/2021 06:27:52AM via free access 42 lAWA Journal, Vol. 18 (1), 1997

Fig. 3. Prosopis alpataco. - a: P. alpataco individuals growing in clayish soils (Asuncion). - b: Cross section, growth ring with vessels mainly solitary (bar = 100 !ill1). - c: Tangential section, homocellular rays, uni-triseriate (bar = 100 J.lm). - d: Radial section, procumbent ray cells (bar = 10 J.lm).

Downloaded from Brill.com10/05/2021 06:27:52AM via free access Villagra & Roig - Edaphic factors and wood structure of Prosopis 43

Wood samples were boiled in water and were cut with a sliding microtome (20 Iilll average thickness). Sections were stained with safranin and mounted in Canada bal• sam. Macerations were made according to Boodle's technique (D' Ambrogio de Argueso 1986) and mounted in glycerine jelly. Quantitative data are based on 25 or more meas• urements per sample. The given values represent the means of each species, extreme values are shown in parentheses. Terms follow the IAWA Committee (1989) list of microscopic features and the 'Multilingual glossary of terms used in wood anatomy' (IAWA Committee 1964). The distribution and proportion of vessels, fibres and parenchyma in each growth ring were estimated in cross sections, adapting the Canfield methodology for the study of plant communities (Mateucci & Colma 1982). Wood element distribution and, hence, proportion, were recorded by using a bi-dimensional chart of the growth ring. This plot was divided into ten equal parts. In each part, two parallel lines (transects) to the growth ring boundary (20 lines per growth ring) were drawn, over which the inter• ception length of each tissue was measured. The tissue proportions of two radii per sample were measured through growth rings developed during the austral summers of 1991192, 1992/93 and 1993/94. Tissue proportions were compared between species and between rings of each species. Data were subjected to the analysis of variance. Since the distribution of variance was not homogeneous, arc sine -Vx transformation was applied to percentages (x) of each tissue in a transverse section (Little & Hills 1975). Means were compared with the Tukey test.

RESULTS

Wood anatomy of Prosopis argentina and P. alpataco Material studied: Prosopis argentina Burk.: Telteca Reserve, (Lavalle) Mendoza, Argentina. DLM (Dendrochronology Lab Mendoza) 558, 559, 560, 598 and 599. - Prosopis alpataco Phil.: Asunci6n, (Lavalle) Mendoza, Argentina. DLM 563, 564, 565,566 and 567. Both species have distinct growth ring boundaries (Fig. 2b & 3b) marked by a radially flattened terminal parenchyma band and differences in vessel diameter, are semi-ring• porous, and have a diagonal to dendritic vessel distribution pattern. Prosopis argentina vessels are mainly in clusters, with some solitary vessels and short radial mUltiples. There are 142 (69-230) vessels per mm2, with a mean of 9 (3-19) vessels per group. In P. alpataco, vessels are mostly solitary and less frequent• ly grouped in short radial multiples and clusters. There are 53 (14-78) vessels per mm2, with a mean of 3 (1-5) vessels per group. Mean vessel diameter in P. argentina is 40 (8-127) 11m, and in P. alpataco 58 (10- 152) Iilll. Prosopis alpataco shows a bimodal diameter distribution (Fig. 4). Vessels were classified into two diameter sizes: 'large' and 'small'. Large diameter vessels are shorter, mainly solitary, and usually have tails. Small diameter vessels are mainly in clusters and have no tails. In P. argentina, large diameter vessels have a mean diameter of74 (45-127) Iilll, and small diameter vessels have a mean of23 (8-43) 11m. In P. al- pataco, large diameter vessels have a mean diameter of 91 (51-152) Iilll, small diam-

Downloaded from Brill.com10/05/2021 06:27:52AM via free access 44 IAWA Journal, Vol. 18 (1), 1997

70 65 60 '"c 55 0 . ~ 50 >.... 45 0 40 .0'" .....0 35 0 30 .... 0 25 .0 E 20 :l Z 15 10 5 0 0-20 31-40 51-60 72-81 92-101 113-122 133-142 21-30 41-50 61-71 82-91 102-112 123-132 143-152 Vessel di ameter ().1m)

Fig_ 4_ Histogram showing frequency distribution of vessel diameters in P. alpataco wood_ Two vessel morphologies corresponding to both vessel diameter sizes are shown at the top of the bars.

eter vessels have a mean of 27 (10-50) I1m- In both species, the wider vessels are mainly in the earlywood. In P. argentina, small diameter vessels are distributed across the entire growth ring, while in P. alpataco, they are mainly in the latewood (Fig. 2b & 3b). Vessel element length also varies with diameter size. In P. argentina, large diameter vessel elements have a mean length of 141 (76-210) Jlffi (60% ofthem with tails), and small diameter vessels have a mean length of 208 (124-294) 11m (without tail). In P. alpataco, large diameter vessel elements have a mean length of 141 (72-210) 11m (50% ofthem with tails), and small diameter vessels have a mean length of 187 (134- 248) Jlffi (without tails). Both species show simple perforation plates in oblique position. Intervessel pits are alternate, small (4-8 Jlffi in diameter) and have a polygonal outline. Vessel-parenchy• ma pits are similar in shape and size to intervessel pits_ Pits are vestured. Axial parenchyma is paratracheal confluent, occasionally aliform or vasicentric. Chambered axial parenchyma with prismatic crystals is common (Fig. 2d). Parenchy• ma cells are fusiform, with 1-4 cells per strand. Disjunctive parenchyma cells are ob• served. Fibres are libriform with minutely bordered pits and thick walls, they are nonseptate. Fibres are very short, with a mean length of 560 (279-838) Jlffi in P. argentina, and 723 (317-1015) 11m in P. alpataco. Gelatinous fibres are common, either in groups or in tangential bands (especially in P. argentina).

Downloaded from Brill.com10/05/2021 06:27:52AM via free access Villagra & Roig - Edaphic factors and wood structure of Prosopis 45

80 Prosopis argentina

70 Prosopis a/pataeo

60 b ~ en 50-1 a I': .€0 8. 40 a 8 0- Il) ::len 30 en a ~ a 20 a 10 a a

0 fibres parenchyma LDV SDV Fig. 5. Tissue proportions in Prosopis argentina and P. alpataco wood. LDV: large diameter vessels. SDV: small diameter vessels. Different letters on the same tissue indicate significant differences at P < 0.05. Vertical lines indicate the standard error. 200 Prosopis argentina 180 a a Prosopis a/pataca 160

en 140 a) en ~ 120 ;> 4-< 0 100 ] a 80 i a 60

40 a

a a a 20 a a a 0 ve/mm2 solitlmm2 SR/mm2 ' group/mm2' ve/clu Fig. 6. Vessels per mm2 (V /mm2), solitary vessels per mm 2 (solitlmm 2), vessels in short radials per mm2 (SR/mm2), grouped vessels per mm2 (group/mm2), and vessels per cluster (V /clu). Different letters indicate significant differences at P < 0.05. Vertical lines indicate the standard error.

Downloaded from Brill.com10/05/2021 06:27:52AM via free access 46 IAWA Journal, Vol. 18 (1), 1997

Rays are homocellular, composed of procumbent cell, and 1-8-seriate. Ray height in P. argentina is 438 (51-1000) J.Illl, and there are 7.6 (5-11) rays per linear mm (Fig. 2c & 2d). In P. alpataco, ray height is 282 (56-856) J.Illl, and there are 8.5 (5-12) rays per linear mm (Figs. 3c & 3d). Ray cells and some vessels of the innermost rings show deposits.

Distribution of elements in transverse section No significant intraspecific differences between rings were found in the proportions of different cell types (vessels, fibres and parenchyma). In contrast, significant differ• ences (p < 0.05) between species were found. A greater proportion of axial parenchy• ma and large diameter vessels was found in P. alpataco, while a greater proportion of fibres and small diameter vessels was found in P. argentina (Fig. 5). Prosopis argentina had a greater mean number of vessels per group, vessels per mm 2 and grouped vessels per mm2, while P. alpataco had a larger number of solitary vessels, and of vessels in short radial multiples, per mm2 (Fig. 6). A decrease in the proportion of the area occupied by vessels (large + small diam• eter) was observed in the latewood of both species (Fig. 7). For large diameter vessels, a decrease was also observed in both species, although P. argentina showed a more pronounced change than P. alpataco (Fig. 8). For smaller diameter vessels there was an increase in P. alpataco across the growth ring, while in P. argentina no changes were observed (Fig. 9). The fibre proportion in both species was markedly lower in the earlywood (Fig. 10).

DISCUSSION

Prosopis alpataco and Prosopis argentina have similar wood structure. They are also similar to other Prosopis species such as P. alba, P. nigra, P. caldenia (Tortorelli 1956), P.flexuosa (Villalba 1985), P. kuntzei and P. vinalillo (Gimenez de Bolzon 1993) and 16 other species cited in Castro (1994). This indicates a relative uniformity in the anatomical wood structure of the genus Prosopis. Table 1 shows the major features of some Prosopis species growing in the Monte Desert. Wood descriptions in this paper generally coincide with those given by Castro (1994), except for the number of vessels permm2. Castro (1994) found in P. argentina 64 (32- 104) vessels per mm2, while in the present work 142 (69-230) vessels per mm2 were found. In P. alpataco, Castro (1994) recorded 245 (50-900) vessels per mm2, whereas the present work recorded 53 (14-78) vessels per mm 2. This is probably explained by differences between Castro's sample sites and ours, which, in tum, may be interpreted as indicating that vessels per mm2 varies considerably with environment. Both species have vessel dimorphism, but P. argentina wood shows a larger propor• tion of small diameter vessels, and a greater number of vessels per group and per mm 2 than P. alpataco. Vessels are mainly grouped in P. argentina while P. alpataco shows a higher proportion of solitary vessels. Vessel grouping and large numbers of vessels per mm2 likely maximize the safety of the hydraulic system, providing alternative ways for water conduction, especially in those species lacking tracheids (Carlquist 1988;

Downloaded from Brill.com10/05/2021 06:27:52AM via free access Villagra & Roig - Edaphic factors and wood structure of Prosopis 47

Vessels 50

45

40 (1) 01) ~ 35 (1) i:! 8.. 30 o:s (1) ~ 25 '0 ~'" 20

15

10

5

Growth ring 1991/92 1992/93 1993/94 Fig. 7. Variation in the proportion of vessels (large diameter + small diameter vessels) through the growth rings of 1991/92,1992/93 and 1993/94.

Prosopis argentina Prosopis alpataco

Large diameter vessels 35

35

30 ~ ~ 25 ~ 0., o:s 20 ~ ] 15 ~ 10

5

o

Growth ring 1991192 1992/93 1993/94 Fig. 8. Variation in the proportion oflarge diameter vessels through the growth rings of 1991/92, 1992/93 and 1993/94.

Downloaded from Brill.com10/05/2021 06:27:52AM via free access 48 IAWA Journal, Vol. 18 (1), 1997

Small diameter vessels 20

18

16 ~ 01) E14 ~ 0 8.. 12 0; ~ 10 '0 '" 8 ~'" 6

4

2

0

Growth ring 1991 1 92 1992/93 1993/94 Fig. 9. Variation in the proportion of small diameter vessels through the growth rings of 1991/92, 1992/93 and 1993/94.

Prosopis argentina Prosopis alpataco

Fibres 60

60

~ 50 01) ~ 8 40 & 0; ~ ~ 30 ] ~ 20

10

o

Growth ring 1991/92 1992193 1993/94 Fig. 10. Variation in the proportion of fibres through the growth rings of 1991/92,1992/93 and 1993/94.

Downloaded from Brill.com10/05/2021 06:27:52AM via free access Villagra & Roig - Edaphic factors and wood structure of Prosopis 49

Zimmermann 1983). Several authors (Fahn & Sarnat 1963; Baas et al. 1983; Carlquist 1988) point out that species with a high percentage of grouped vessels are common in arid environments. A large number of vessels per group suggests xeromorphism (Carl• quist & Hoekman 1985). Prosopis alpataco and P. argentina are both semi-ring-porous, but P. argentina shows a strong decrease in the proportion of large diameter vessels through the ring, while in P. alpataco these differences are less obvious. All the characteristics above suggest that in the Monte Desert the wood of P. argentina tends to be xeromorphic, a fact that is interpreted as a strategy to maximize water con• duction safety, which enables the plant to resist extreme events of water stress in arid environments. On the other hand, the wood of P. alpataco shows features that tend to be mesomorphic, maximizing water conduction efficiency. The aforementioned differences between the wood of P. argentina and P. alpataco can be accounted for by the life form strategies of these species. Following the classi• fication given by Solbrig et al. (1977), P. argentina could be considered as an 'ever• green shrub' . Species with this life form, known as 'true xerophytes', develop a series of xeromorphic features that allow soil water extraction and photosynthesis at very negative soil water potentials. Examples of these xeromorphic features are leaf reduc• tion, photosynthesizing green stems, thick cuticles, the capacity to withstand negative water pressures. Wood structure should be considered as one of the xeromorphic char• acteristics of P. argentina. According to Roig (1987, 1993) and Solbrig et al. (1977), P. alpataco could be considered as a phreatophyte. The development of a deep root system gives this spe• cies the possibility of reaching underground water, and thus access to the water supply may allow different degrees of mesomorphism, depending on the predictability of water availability. Carlquist and Hoekman (1985) stated that the desert phreatophytes are essentially opportunists in their ability to develop deep roots, therefore wood adapta• tions to drought are relatively few. We suggest that the ability of P. alpataco to occupy clayish and saline soils is probably related to the type of root architecture and not to wood structure. Villalba and Bonisegna (1989) analyzed the wood structure of P.flexuosa from the inner rings to the bark. The proportions of the different tissues of P. argentina are sim• ilar to those of P. flexuosa in its early years. However, P. alpataco shows values similar to those of the older wood of P. flexuosa, when this species has reached the phreatic layer. It would be interesting to study age-related changes in the wood of P. alpataco. The high proportion of gelatinous fibres observed in P. argentina may be related to mechanical stress in stems (Metcalfe & Chalk 1983), perhaps provoked by the activity of sand dunes.

CONCLUSIONS

Prosopis argentina, growing in sand dunes, develops a hydraulic architecture that might be capable of making maximum use of available water, but might also be capable of maximizing the safety of the water-conducting system through the presence of a large

Downloaded from Brill.com10/05/2021 06:27:52AM via free access 50 lAWA Journal, Vol. 180),1997 number of grouped vessels and small diameter vessels. This structure may allow it to withstand the extreme events of water stress, typical of sand dunes. Prosopis aipataco, though prevalent in clayish and somewhat saline soils, has wood with a tendency towards mesomorphism, with a greater proportion of solitary and large diameter vessels. This species has a deep root system that enables it to reach underground water, and get a regular water supply. Consequently, it likely achieves a relative independence from the variations in water availability of the upper soil layers.

ACKNOWLEDGEMENTS

To Dr. E. Ancibor, lng. J. Bonisegna, lng. F. Roig, lng. S. Trione for their ideas and suggestions, to Dr. E.A. Wheeler for her helpful comments, to M.E. Soler and N. Horak for the English version.

REFERENCES

Baas, P. & S. Carlquist. 1985. A comparison of the ecological wood anatomy of the floras of southern California and Israel. IAWA Bull. n.s. 6: 349-353. Baas, P., E. Werker & A. Fahn. 1983. Some ecological trends in vessel characters. IAWA Bull. n.s.4: 141-160. Burkart, A. 1976. A monograph of the genus Prosopis (Leguminosae subfam. Mimosoideae). J. Arnold Arbor. 57: 219-249; 450-455. Burkart, A. & S. Simpsom. 1977. The genus Prosopis, an annotated key to the species of the world. In: B.B. Simpson (ed.), Mesquite, its biology in two desert scrub ecosystems. US/ IBP Synthesis 4: 201-216. Dowden, Hutchinson & Ross, Inc. Cabrera, A.L. 1976. Regiones fitogeognHicas argentinas. In: w.P. Kugler (ed.), Enciclopedia Argentina de Agricultura y Jardineria. ACME. Buenos Aires. 85 pp. Carlquist, S. 1988. Comparative wood anatomy. Springer-Verlag, Berlin, Heidelberg. 435 pp. Carlquist, S. & D.A. Hoekman. 1985. Ecological wood anatomy of the woody southern Californian flora. IAWA Bull. n.s. 6: 319-347. Carman, N. J. 1973. Systematic and ecological investigations in the genus Prosopis (Mimosoideae) emphasizing the natural products chemistry. PhD Thesis, Univ. Texas, Austin, Texas. Castro, M.A. 1994. Maderas argentinas de Prosopis. Atlas anatomico. Secretaria General de la Presidencia de la Nacion. Republica Argentina. 101 pp. Dalmasso, A., M. Homo & R.J. Candia. 1988. Utilizacion de especies nativas en la fijacion de medanos. In: Fundacion Cargill (ed.), Erosion: Sistemas de produccion, manejo y conser• vacion del suelo y del agua: 221-289. Buenos Aires. D' Ambrogio de Argueso, A. 1986. Manual de tecnicas en histologfa vegetal. Editorial Hemisferio Sur. Buenos Aires. 84 pp. D'Antoni, H.L.D. & O.T. Solbrig. 1977. Algarrobos in South American cultures: past and present. In: B.B. Simpson (ed.), Mesquite, its biology in two desert scrub ecosystems. US/ IBP Synthesis 4: 189-200. Dowden, Hutchinson & Ross, Inc. Fahn, A. 1964. Some anatomical adaptations of desert plants. Phytomorphology 14: 93-102. Fahn, A. & c. Samat. 1963. Xylem structure and annual rhythm of development in trees and shrubs of the desert. IV. Shrubs. Bull. Res. Council Israel 11: 198-209. Gimenez de Bolzon, A.M. 1993. Rasgos estructurales caracteristicos del xilema secundario de las principales especies arboreas de la Region Chaquefia Seca. Quebracho (Santiago del Estero, Argentina) I: 5-14.

Downloaded from Brill.com10/05/2021 06:27:52AM via free access Villagra & Roig - Edaphic factors and wood structure of Prosopis 51

IAWA Committee. 1964. Multilingual glossary of terms used in wood anatomy. Konkordia, Winterthur. 184 pp. IAWA Committee. 1989. List of microscopic features for hardwood identification. IAWA Bull. n.s. 10: 219-332. Lindorf, H. 1994. Eco-anatomical wood features of species from a very dry tropical forest. IAWA 1. 15: 361-376. Little, T.M. & F.J. Hills. 1975. Metodos estadisticos para la investigaci6n en la agricultura (10 ed.). Editorial Trillas. Mexico. 270 pp. Mateucci, S. & A. Colma. 1982. Metodologia para el estudio de la vegetaci6n. Monograffa N° 22. Secretarfa General Organizaci6n de los Estados Americanos. 168 pp. Metcalfe, c.R. & L. Chalk. 1983. Anatomy of the Dicotyledons. Vol. II. Wood structure and conclusion of the general introduction. Second Edition. Clarendon Press, Oxford. Morello, 1. 1958. La Provincia Fitogeografica del Monte. Opera Lilloana 2: 5-115. Roig, F.A. 1987. Arboles y arbustos en Prosopis flexuosa y P. alpataco. Parodiana 5: 49-64. Roig, F.A. 1993. Informe nacional para la selecci6n de germoplasma en especies del genero Prosopis de la Republica Argentina. In: Unidades de Botanica y Fisiologia Vegetal (IADIZA) (eds.), Contribuciones Mendocinas a la Quinta Reuni6n Regional para America Latina y el Caribe de la Red de Forestaci6n del CUD. Conservaci6n y Mejorarniento de Especies del Genero Prosopis. (Mendoza, Argentina). pp. 1-36. Roig, F. A., M. Gonzalez Loyarte, E. Martinez Carretero, A. Berra & C. Wuilloud. 1992. La Tra• vesia de Guanacache, Tierra Forestal. Multequina (Mendoza, Argentina) 1: 83-91. Simpson, B.B. & O.T. Solbrig. 1977. Introduction. In: B.B. Simpson (ed.), Mesquite, its biol• ogy in two desert scrub ecosystems. US/IBP Synthesis 4: 1-26. Dowden, Hutchinson & Ross, Inc. Solbrig, O.T., M.A. Barbour, 1. Cross, G. Goldstein, C.H. Lowe, J. Morello & T.w. Yang. 1977. The strategies and community patterns of desert plants. In: G.H. Orians & O.T. Solbrig (eds.), Convergent evolution in warm deserts. US/IBP Synthesis 3: 67-106. Dowden, Hutchinson and Ross, Inc. Tortorelli, L.A. 1956. Maderas y Bosques Argentinos. Buenos Aires. ACME. 910 pp. Villalba, R. 1985. Xylem structure and cambial activity in Prosopis flexuosa DC. IAWA Bull. n.s. 6: 119-130. Villalba, R. & J.A. Bonisegna. 1989. Dendrochronological studies on Prosopis flexuosa DC. IAWABull.n.s.lO: 155-160. Zimmermann, M.H. 1983. Xylem structure and the ascent of sap. Springer-Verlag, Berlin, Hei• delberg. 143 pp.

Downloaded from Brill.com10/05/2021 06:27:52AM via free access