Morphological Variability of Nitraria Species in Central and Southern Kazakhstan

Abstract

The variability of metric traits has been studied in 20 Kazakhstan populations of three Nitraria species (N. schoberi L., N. sibirica Pall., and N. komarovii Iljin & Lava ex Bobrov). According to the results, N. sibirica differs from N. schoberi and N. komarovii in small leaves, fruits, and seeds, as well as in the structural features of inflorescences and flowers. N. sibirica is characterized by a greater number of flowers per inflorescence (25–66 on average) than N. schoberi and N. komarovii (14–28 on average). Additionally, N. sibirica differs from N. schoberi by narrower (1.3×) petals and smaller anthers (1.46× in length and 1.2× in width) and pistils (1.25× in length and 1.44× in width). N. komarovii differs from N. schoberi by narrower leaves (1.7×). N. komarovii is characterized by relatively large (especially in width) size of anthers that, together with smaller petals, makes it possible to distinguish this species during flowering. Flowers of N. komarovii are bright yellow, while those in N. schoberi and N. sibirica are white and light purple, respectively. N. komarovii fruits are orange, pale red, or bright red. Fruits of N. schoberi and N. sibirica are dark burgundy and black, respectively. At the intraspecific level, most of the studied metric traits (except for the habitus of N. sibirica plants) are stable and do not depend on the 16 climatic parameters of plant habitats. At the same time, a number of morphological features have been revealed in N. sibirica plants from the Ili Depression. In these populations, N. sibirica plants form shrubs up to 1.8 m in height with a large (up to 90) number of flowers per inflorescence, large petals (3.5 mm in length and 2.2 mm in width on average), small (~0.6 mm) anthers, small (5–5.5 mm in length) fruits, and small (~4 mm in length) narrow ovate stones. These features indicate the ecological–geographical differentiation of N. sibirica under the extra-arid conditions of the stony desert of the depression and evidence a separate taxonomic rank of these populations.

Pollen Morphology of Some Species from Genus Nitraria

“…Striae are relatively loose, packed in the mesocolpia, and short (Figure 3k,l). Previously, we have documented differences between the populations of N. sibirica from Basshi and Taskarasu in many morphological traits of vegetative and generative organs, bush habitus [30], the profile and levels of phenolic compounds [31,32], and in the analysis of the ITS2 region of nuclear ribosomal DNA [33,34]. The above findings support the taxonomic separation of these populations.…”

Integrative Taxonomy of Nitraria (Nitrariaceae), Description of the New Enigmatic Species and Key to All Currently Known Species

“…Analysis of the sequence of the ITS of the nuclear ribosomal DNA identified two main N. sibirica ribotypes [ 32 , 33 ]. The heterogeneity of N. sibirica is also supported by data on composition and content of phenolic compounds in plants from Siberian and Kazakh populations [ 34 ] and the presence of morphological differences in plants from these populations [ 4 , 35 ].…”