Comparison of Initial Growth Responses to Water Availability of Two Chinese Desert Dune Species and Nine Cultivated Species

Seed traits and germination responses to water availability can be related to seedling emergence and survival in sand and thus can affect the adaptability of species to desert dune environments. Water absorption by seeds, germination speed, responses of germination to water stress (imposed using polyethylene glycol-6000), and the effects of irrigation on seedling emergence and survival in sand were compared among two desert dune herbs from northeastern China (Astragalus adsurgens and Melilotus albus) and nine cultivated species (lettuce, carrot, turnip, sesame, Welsh onion, radish, cucumber, barley, and snap bean). Seeds that germinated rapidly after irrigation, those that germinated under low water potential, and those with small dry weight tended to produce emergent seedlings in response to a smaller amount of irrigation. However, these seedlings did not survive long, indicating that ready seedling emergence did not always promote seedling establishment. Drought resistance of seedlings was not correlated with seed traits or germination responses. The results indicated that the desert dune species were not less sensitive to water deficiency than the cultivated species at the initial growth stage. This may result from the fact that precipitation occurs predominantly during the summer in the desert dunes of northeastern China. As a result, species tend not to suffer from water deficiency during the initial growth stage.