Kaempferia galangal, belonging to the ginger family, is an important plant widely used as a traditional spice and medicine in Asia. Recent cytological studies show that Kaempferia has various ploidy levels. K. galanga var. latifolia, a variety of K. galanga, is morphologically different from K. galanga var. galanga by the suborbicular leaves with short petiole and leaves laying on the ground. However, some species ploidy level remains unexplored. 

In a study published in Scientia Horticulturae, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) systematically analyzed the differences between K. galanga var. galanga and K. galanga var. latifolia using cytology, morphological comparisons of leaves, stomata, flowers, and active compounds. 

The researchers used flow cytometry (FCM) to measure cell types (cytotypes) and found that K. galanga var. latifolia is tetraploid while K. galanga var. galanga is pentaploid. Leaves of tetraploid Kaempferia galanga var. latifolia are wider compared with pentaploid Kaempferia galanga var. galanga. 

Comparative analyses of morphological characters showed that polyploidization significantly affected some traits; tetraploid individuals had wider leaves, and pentaploid individuals displayed a higher stomatal density, wider lateral staminodes, longer bracteoles, and bracts. 

The results confirmed that the morphological differences are explained by the different cytotypes. Pentaploids had bigger flowers, higher stomatal density, and higher (E)-Ethyl-p-methoxycinnamate (EPMC) content in rhizomes than the tetraploids. Kaempferia has multiple ploidy levels from 2x, 3x, 4x, to 5x. 

"We believe that including more species and varieties would help to explain more unknown biological phenomena, and provide a reference for spice crops breeding,” said XU Youkai of XTBG. 

Contact 

XU Youkai 

Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun 666303, Yunnan, China                       

E-mail:  xyk@xtbg.org.cn     

Kaempferia galanga var. galanga (Image by LU Jianmei) 

Kaempferia galanga var. galanga (Image by LU Jianmei) 

Kaempferia galanga var. latifolia (Image by LU Jianmei) 

Kaempferia galanga var. latifolia  (Image by LU Jianmei)