Abstract
Lemongrass [Cymbopogon citrates (DC) Stapf] is a cosmopolitan economically important grass with a natural potential to
adapt to different climates. However, the mechanisms of cross-locational adaptability are not studied in this grass species. To
explore some physiological basis of cross-locational adaptability potential of lemongrass, experiments were performed on one
population each from Faisalabad and Quetta, Pakistan. Both the population were planted at both the locations in a reciprocal
swap arrangement using randomized complete block design with three replicates. The data were recorded on monthly basis
from June to December over two consecutive years (2015 and 2016). The swap reciprocated lemongrass populations from
Quetta and Faisalabad exhibited differential growth patterns from their native counterparts thus showing flexibility among the
populations. Enhanced tillering, root proliferation and increased dry shoot and root weight was observed in the Quetta
population adapted in Faisalabad. However, Faisalabad population adapted in Quetta produced taller plants with longer roots,
while tillering and number of leaves were greatly reduced in the Quetta adapted population as compared to its counterpart in
Faisalabad. Tissue analysis for hydrogen peroxide (H2O2) and malondialdehyde (MDA) data revealed that both the native and
adapted populations in Faisalabad accumulated greater H2O2 and MDA in summer months while Quetta population did so in
the winter months, thus showing that summer months in Faisalabad and winter months in Quetta to be stressful for the
populations in the respective locations. Both native and adapted populations in Quetta displayed dark green leaf color, which
was accompanied by increased chlorophyll a and b contents in summer months in Quetta and winter months in Faisalabad,
while carotenoids accumulation was greater in the season with high temperature in Faisalabad and chilling temperature in
Quetta. Fitting regression equation and finding correlation between maximum and minimum temperatures and relative
humidity (RH) revealed negative correlations of temperatures with growth, H2O2 and MDA at both the locations in native and
adapted population, while positive correlation of chlorophylls and carotenoids at Quetta and negative ones at Faisalabad, while
RH was regressed with none of these attributes (data not shown). This implied that temperature was a major determining factor
in the adaptation of populations at either location based on flexibility in physiological adjustments at both the locations.
