Wednesday, July 3, 2024

[Botany • 2024] Kaempferia calcicola • Cytotaxonomy of Kaempferia subgenus Protanthium (Zingiberaceae) supports A New limestone Species endemic to Thailand

   Kaempferia calcicola Noppornch.

in Nopporncharoenkul, Sukseansri, Nopun, Meewasana, Jenjittikul, Chuenboonngarm, Viboonjun et Umpunjun, 2024. 
ดอกดินเขาหินปูน  ||   DOI: 10.3372/wi.54.54201

Thailand is the biodiversity hotspot of genus Kaempferia (Zingiberaceae) and harbours 14 species belonging to K. subgenus Protanthium. To better understand the taxonomic circumscription and verify the taxonomic status, the present characterization of cytogenetic characters included all recognized and one undescribed species of K. subg. Protanthium from Thailand. Overall, 88 accessions of plant materials were analysed cytogenetically: 84 and 42 accessions were subjected to flow cytometry and karyology, respectively. Based on genome size and mitotic chromosome numbers, 74 accessions from all species investigated were putative diploid, whereas the others were putative polyploid: triploid (three accessions) and tetraploid (11 accessions). The cytogenetic evidence indicates that 2n = 2x = 22 is the diploid number and x = 11 is the base chromosome number for K. subg. Protanthium. The genome sizes among the diploid accessions ranged from 3.687 to 6.412 pg while high intraspecific variation in genome size was observed with up to 19.4%. Two species included accessions with different ploidy levels: K. rotunda L. (diploid, triploid and tetraploid) and K. takensis Boonma & Seansouk (diploid and tetraploid). The increase in genome size of tetraploid K. rotunda is nearly in correlation to the increase in ploidy level, whereas the triploid plants represent genome expansion with an approximately 11% larger than expected genome. Interestingly, tetraploid K. takensis displays genome downsizing of 15.3% compared to their diploids. The cytogenetic characteristics, together with morphology, unequivocally clarify the taxonomic status of a new species, named Kaempferia calcicola Noppornch. A revised identification key to species of K. subg. Protanthium is provided.

KEYWORDS: chromosome number, cytogenetics, Cytotaxonomy, genome size, Kaempferia, Kaempferia subg. Protanthium, Khon Kaen province, new species, polyploidy, species circumscription, taxonomy, Thailand, Zingiberaceae

Kaempferia calcicola.
  A: habitat with plants in flowering period; B: plant habit in flowering period; C: inflorescences and flowers in top view; D: habitat with plants in rainy season; E. plant habit in rainy season.
– All photographs taken at type locality: Thailand, Khon Kaen Province, Phu Pha Man District, A: 27 Apr 2023; B, C: 6 Apr 2024; D, E: 29 Aug 2023, by N. Nopporncharoenkul.

Kaempferia calcicola Noppornch., sp. nov.  

Diagnosis — Kaempferia calcicola Noppornch. is similar to K. takensis Boonma & Seansouk in overall habit, inflorescence and floral plane, but differs by anther crest obreniform, broadly ovate, obovate to obdeltoid (vs anther crest oblong to ovate in K. takensis) with irregular undulate to crenate apex (vs bilobed to irregularly tridentate apex, usually with 2–3 small teeth between lobes in K. takensis) and labellum with an incision c. 3/5 of its length (vs labellum with an incision more than 2/3 of its length in K. takensis). It is also similar to K. lopburiensis Picheans. in inflorescence, floral plane and flower colour, but differs by prominent pseudostem upright above ground (vs pseudostem short and completely embedded in soil in K. lopburiensis), leaf blades elliptic, elliptic-oblong to lanceolate-oblong and longer petiole 3–18(–30) cm long (vs leaf blades suborbicular to ovate, adpressed on ground and subsessile petiole in K. lopburiensis).

Floral morphology of Kaempferia subg. Protanthium in Thailand
 A: K. albiflora (NNSB-546); B: K. aurora (NNSB-713); C: K. caespitosa (NNSB-733); D: K. calcicola (NNSB-903);
E: K. graminifolia (NNSB-686); F: K. grandifolia (NNSB-519); G: K. jenjittikuliae (NNSB-760); H: K. lopburiensis (NNSB-541);
I: K. noctiflora var. noctiflora (NNSB-554); J: K. noctiflora var. thepthepae (NNSB-928); K: K. rotunda (NNSB-534); L: K. simaoensis (NNSB-676);
M: K. sipraiana (NNSB-656); N: K. subglobosa (NNSB-749); O: K. takensis (NNSB-697); P: K. udonensis (NNSB-508).
 All photographs by N. Nopporncharoenkul.

Nattapon Nopporncharoenkul, Wiphada Sukseansri, Possathorn Nopun, Jiraporn Meewasana, Thaya Jenjittikul, Ngarmnij Chuenboonngarm, Unchera Viboonjun and Puangpaka Umpunjun. 2024. Cytotaxonomy of Kaempferia subg. Protanthium (Zingiberaceae) supports A New limestone Species endemic to Thailand. Willdenowia. 54(2); 149-121. DOI: 10.3372/wi.54.54201