Abstract

CARO, María; RUIZ, Ana; PAEZ, Valeria  and  ALBORNOZ, Patricia. Morphology, vegetative micrographic parameters, histochemistry and cytogenetics of Adesmia trijuga (Leguminosae, Papilionoideae) in northwestern Argentina. Lilloa [online]. 2020, vol.57, n.2, pp.110-124. ISSN 0075-9481.  http://dx.doi.org/https://doi.org/10.30550/j.lil/2020.57.2/3.

Adesmia trijuga is a thorny, microphyll, native and perennial shrub; growing between 1100-3000 m a.s.l. in mountainous regions of humid ravines or arid and rocky areas; it is commonly known as "cuerno de cabra", "añagua" or "suncho". A. trijuga is a polymorphic species with pinnate leaves with 3-5 pairs of leaflets with forage properties, used as firewood and widely distributed in Argentina and Chile. Back- ground knowledge on the topic refers only to the cytogenetics of populations in the Cuyo Region. The objective of this work is to establish the vegetative, histochemical and cytogenetic micrographic parameters to characterize A. trijuga in populations of Northwestern Argentina. Five individuals were randomly collected from populations located in Jujuy, Salta and Tucumán. The material was fixed in FAA and herborized; traditional anatomical, histochemical and cytogenetic techniques were applied. The results evidenced paripinnateleaves, microphylls, with leaflets of entire leaf blade, symmetrical, obovate, and pinnate-camptodromous-eucamptodromous venation. Amphistomatic leaflets, pubescent in both epidermis, with eglandular and glandular trichomes the last being of three types; isodiametric to rectangular epidermal cells, with straight to curved walls with striated cuticle; anomocytic, hemibrachyparacytic, brachyparacytic, amphibrachyparacytic, hemi-amphibrachyparacytic, and hemiamphicyclocytic stomata; equilateral mesophyll; collateral vascular bundles with a sclerenchyma cap towards the phloem surrounded by parenchyma sheath. Petiole subcircular with eglandular and glandular trichomes identical to those of the foliolate lamina; 2-3 subepidermal layers of palisade chlorenchyma; five collateral vascular bundles. Thorns circular in outline, with secondary growth, abundant sclerenchyma and with trichomes identical to those of the leaflet blade and petiole. Tubes and idioblasts containing phenolic substances are present in the mesophyll, in the petiole pith, and spines. The chromosome number was 2n= 20. The elements of diagnostic value are the type of trichomes, the amount and position of mechanical tissue, phenol-producing idioblasts and tubes, and the chromosome number.

Keywords : Adesmia; anatomy; citology; morphology.

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