Paper Details

PJB-2025-212

The impact of drought stress on two medicinal plants in karst areas

Hong Jiang, Zhibao Wang, Abdul Majeed Baloch, Jalil Ahmed, Abdul Wahid Baloch, Qin Ling, Liuhong Wu, Jiangping Wen and Jiangqing Yu
Abstract

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Karst ecosystems are characterized by shallow soils, rapid water loss, and frequent seasonal drought, posing significant challenges to the growth and sustainability of medicinal plants. To investigate drought-induced morphological adjustment patterns in karst medicinal species, a controlled pot experiment was conducted using two representative plants, Bulbophyllum odoratissimum and Pyrrosia petiolosa. Five soil moisture gradients were applied to simulate increasing drought intensity. Key morphological traits, stomatal density, and root and aboveground biomass were measured to evaluate plant responses to water deficit. The results showed that increasing drought stress significantly affected all measured morphological indices and biomass parameters in both species (P < 0.05). Under extreme drought conditions, aboveground biomass declined by 54.19% in B. odoratissimum and 57.40% in P. petiolosa, while root biomass decreased by 42.19% and 42.55%, respectively. Leaf length, width, thickness, and area exhibited progressive reductions with increasing drought severity. In contrast, stomatal density displayed a unimodal response, increasing under mild to moderate drought and declining under severe drought stress. Notably, the magnitude of variation in most morphological traits and stomatal density was greater in P. petiolosa than in B. odoratissimum. These findings indicate species-specific differences in drought sensitivity, with B. odoratissimum exhibiting relatively lower morphological sensitivity to drought stress compared to P. petiolosa. The study highlights the utility of integrative morphological indicators for assessing drought response strategies in medicinal plants and provides a scientific basis for the selection and management of drought-tolerant species in karst environments

To Cite this article: Jiang, H., Z. Wang, A.M. Baloch, J. Ahmed, A.W. Baloch, Q. Ling, L. Wu, J. Wen and J. Yu. 2026. The impact of drought stress on two medicinal plants in karst areas. Pak. J. Bot., 58(6): DOI: http://dx.doi.org/10.30848/PJB2026-6(8)  
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