抄録
Understanding the effects of drought and salinity stress on seed germination is essential for selecting species for arid tropical regions. The type of substrate used in germination tests further offers new perspectives on the response to drought and salinity stress. In this study, we aimed to evaluate seed germination in two fruit species (Hylocereus undatus and Carica papaya) and two cereal species (Oryza sativa and Triticum aestivum) under drought and salinity conditions on two substrates (filter paper and Kanuma soil). We established 16 treatments combining four drought stress levels (0, 50, 100, and 200 g L−1 of PEG-6000 solution) and four salinity stress levels (0, 200, 400, and 800 mmol L−1 of NaCl solution) on the two substrates, and observed seed germination in the target species. In all the species, germination rates decreased with drought and salinity stress; no synergistic effect was detected. Compared to filter paper, Kanuma soil mitigated the negative impact of drought and salinity stress on germination, particularly in the cereal species. On Kanuma soil, Triticum aestivum had higher tolerance to severe salinity stress, whereas O. sativa had greater tolerance to moderate salinity stress. In the fruit species, H. undatus was more tolerant to salinity stress than C. papaya. Based on these results, we recommend cereal species, rather than fruit species, for seeding in arid and semi-arid tropical regions. However, species showing greater tolerance than T. aestivum should be sought using seed germination tests on different agricultural soils.
