Effects of Temperature, Dry Storage, and Burial on Dormancy and Germination of Seeds of 13 Desert Plant Species from Sand Dunes in the Gurbantunggut Desert, Northwest China

Abstract

Temperature, dry storage, and burial are three factors that can potentially affect seed dormancy and germination. We investigated the influence of dry storage and burial on breaking primary dormancy and on germination of the seeds of 13 desert species in different temperature regimes. Germination percentages of freshly matured seeds differed significantly among species in the same temperature regime, indicating that each species had a particular temperature requirement. Except for Minuartia regeliana and Stipagrostis pennata, the species required a longer time to initiate germination at 15/5°C than at 25/10°C or 35/20°C. Seed germination of Leymus racemosus, Ceratocarpus arenarius, Artemisia ordosica, Cousinia affinis, Bassia dasyphylla, and Agriophyllum squarrosum was more sensitive to change in thermoperiod than that of the other species. Except for B. hyssopifolia and Petrosimonia sibirica, fresh seeds of the species have different degrees of primary dormancy. Germination did not differ among life forms, except for the annuals P. sibirica and B. hyssopifolia and the shrubs Artemisia ordosica. Germination percentage of both annuals and perennials was generally less than 50%. Seed germination percentages differed significantly in the dry storage and buried storage treatments. Dry storage increased germination percentages of A. ordosica, C. arenarius, B. dasyphylla, and C. affinis, and burial increased germination percentages of A. ordosica, Chenopodium aristatum, C. arenarius, B. dasyphylla, Horaninowia ulicina, Cousinia affinis, and L. racemosus. Except for A. ordosica and L. racemosus, germination percentages of the species did not reach 50%, thus burial treatments did not completely break physiological dormancy. Both dry storage and burial decreased germination percentage of (viability test) P. sibirica, indicating that dehydration, hypoxia, fluctuating water content, and/or frequent temperature fluctuations may induce seeds into secondary dormancy.