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XI Съезд Русского ботанического общества

generated based on chloroplast

rbcL

gene sequences from 108 species of these two families. In addition, the

nuclear ribosomal transcribed spacer (ITS) region was/is sequenced in numerous taxa o f

Suaedoideae

(43

spp.),

Camphorosmeae

(43 spp. so far) and

Salsoleae

(71 spp. so far) in order to get an independent data set

and a better resolution in groups particularly rich in C4 taxa. Phylogenetic trees obtained from maximum

parsimony and maximum likelihood analysis were/are cross-checked and compared with the results of anatomical

studies (Kadereit et al.2003).

Results

The

rbcL

and the ITS phytogenies allow a first"estimate of the number and topologies of C4 lineages in

Chenopodiaceae

. We found strong molecular evidence for 10 independent shifts from C3 to C4 photosynthesis, and

weak support for 6 more, numbers far higher than suggested before (4) on base of leaf anatomy by Carolin et al.

(1975, 1982). Most C4 lineages correspond to particular C4 leaf types. In

Chenovodioideae

(sect

Atripliceae

s. str.)

the C4pathway is restricted to

Atriplex.

Within that genus, one C4 lineage corresponds with the

Atriplex halimus

leaf

type, whereas a second, probably independent shift to C4might be associated with the

A. dimorphostegia

type which

differs by lack of hypodermis. In

Saiicomioideae

(tribe

Salicornieae

), a single C4 origin in

Halosarcia

corresponds

with the

Halosarcia indica

type of stem cortex. In

Suaedoideae

four shifts are reflected in the

Bienertia, Borszczowia,

Schoberia

and

Salsina

leaf types, as was postulated before from relevant anatomical studies byFreitag and Stichler

(2002). In

Camphorosmeae

which proved to be closely related to

Salsoleae

and should be included in

Salsoloideaef

at least one origin occurred in the

Kochia prostrata

clade and probably a second one in the

Camphorosma

subclade.

The three leaf types found in

Camphorosmeae

, viz the

K. laniflora

K. prostrata

and

Kirilowia

type, do not correspond

to the different lineages.

Salsoleae

contain the bulk of C4 species. At least three independent shifts are indicated, but

so far no clear-cut relationships between C4 lineages and the 5-7 different C4 leaf types could be found.

Conclusions

With c. 45 genera and c. 570 species performing C4photosynthesis,

Chenopodiaceae

is the most prominent C4

family among dicots. In that family, contrary to the widely accepted hypothesis on the dominant impact of reduced

PCOv

(e. g., Sage, 2001), C4photosynthesis is interpreted as a most successful evolutionary response to permanent

shortage in water supply, with high temperatures and strong radiation input being necessary preconditions. Diversity in

leaf anatomy is higher than in any other family, presumably because evolution of C4 leaf types started very early in

geologic histoiy and from different C3 leaf types. However, while some C4 clades were extremely successful in terms

of species diversity (e. g.,

Atriplex

Salsoleae

Suaeda

sect.

Salsina)

and with regard to ecophysiological and competitive

fitness, others obviously were not (e, g.

Bienertia

Halosarcia

). The conclusion is drawn that the invention of C4

photosynthesis as such does not guarantee evolutionary success in terms of species diversification. The efficiency of C4

photosynthesis may differ among anatomical leaf types and biochemical subtypes, and its contribution to fitness might

be hampered by other anatomical, morphological and physiological properties of the taxa concerned. Our data strongly

suggest independent origins of the two biochemical subtypes of C4 photosynthesis known from

Chenopodiaceae

because in any C4 clade either the NAD-ME or the NADP-ME subtype had been found so far.

REFERENCES

Carolin R. C, Jacobs S W.L

and

Vesk

M Leaf structure in

Chenopodiaceae

// Bot. Jahrb. Syst, 1975. - Vol. 95. - P. 226-255.

Carolin R.C

Jacobs S. W.L.

and

Vesk M.

The chlorenchyma of some members of the

Salicornieae

(

Chenopodiaceae)

Austr. J. Bot., 1982. - Vol. 30. - P. 387-392.

FreitagH.

and

Stichler W Bienertia cycloptera

Bunge ex Boiss.,

Chenopodiaceae

, another C4plant without Kranz tissues /

/ Plant Biol., 2002. - Vol. 4. - P. 121-131.

Kadereit G, Borsch XWeisingK.

and

FreitagH.

Phylogeny of

Amaranthaceae

and

Chenopodiaceae

and the evolution of

C4photosynthesis // Int. J. Plant Sci., 2003, (in press).

Sage R.F

Environmental and evolutionary preconditions for the origin and diversification of the C4photosynthetic syndrome /

/ Plant Biol., 2001. - Vol. 3. - P. 202-213.

СОДЕРЖАНИЕ ХЛОРОФИЛЛА И ИНТЕНСИВНОСТЬ ФОТОСИНТЕЗА НЕКОТОРЫХ

ДРЕВЕСНЫХ ИНТРОДУЦЕНТОВ В УСЛОВИЯХ ГОРОДСКОЙ СРЕДЫ

Калашникова Л. М., Цепкова Н. Л.*

Кабардино-Балкарский госуниверситет, *Кабардино-Балкарская госсельскохозяйственная академия

г. Нальчик

Влияние городской среды сказывается на самых разных сторонах жизнедеятельности растений. Фото

синтезирующий аппарат, имеющий огромную поверхность контакта с окружающей средой, в первую очередь

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