Seed dormancy, seedling establishment and dynamics of the soil seed bank of Stipa bungeana (Poaceae) on the Loess Plateau of northwestern China.
Studying seed dormancy and its consequent effect can provide important information for vegetation restoration and management. The present study investigated seed dormancy, seedling emergence and seed survival in the soil seed bank of Stipa bungeana, a grass species used in restoration of degraded land on the Loess Plateau in northwest China. Dormancy of fresh seeds was determined by incubation of seeds over a range of temperatures in both light and dark. Seed germination was evaluated after mechanical removal of palea and lemma (hulls), chemical scarification and dry storage. Fresh and one-year-stored seeds were sown in the field, and seedling emergence was monitored weekly for 8 weeks. Furthermore, seeds were buried at different soil depths, and then retrieved every 1 or 2 months to determine seed dormancy and seed viability in the laboratory. Fresh seeds (caryopses enclosed by palea and lemma) had non-deep physiological dormancy. Removal of palea and lemma, chemical scarification, dry storage (afterripening), gibberellin (GA3) and potassium nitrate (KNO3) significantly improved germination. Dormancy was completely released by removal of the hulls, but seeds on which hulls were put back to their original position germinated to only 46%. Pretreatment of seeds with a 30% NaOH solution for 60 min increased germination from 25% to 82%. Speed of seedling emergence from fresh seeds was significantly lower than that of seeds stored for 1 year. However, final percentage of seedling emergence did not differ significantly for seeds sown at depths of 0 and 1 cm. Most fresh seeds of S. bungeana buried in the field in early July either had germinated or lost viability by September. All seeds buried at a depth of 5 cm had lost viability after 5 months, whereas 12% and 4% seeds of those sown on the soil surface were viable after 5 and 12 months, respectively.
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China.
Xiao Wen
XW
Hu
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China.
Yan Pei
YP
Wu
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China.
Xing Yu
XY
Ding
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China.
Rui
R
Zhang
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China.
Yan Rong
YR
Wang
Department of Biology, University of Kentucky, Lexington, Kentucky 40506-0225, United States of America.
Jerry M
JM
Baskin
Department of Biology, University of Kentucky, Lexington, Kentucky 40506-0225, United States of America; Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546-0312, United States of America.
Carol C
CC
Baskin
D000704:Analysis of Variance; D002681:China; D003247:Conservation of Natural Resources / Q000379:methods*; D018525:Germination / Q000187:drug effects / Q000502:physiology; D005875:Gibberellins / Q000494:pharmacology; D009566:Nitrates / Q000494:pharmacology; D057445:Plant Dormancy / Q000502:physiology*; D006109:Poaceae / Q000502:physiology*; D017680:Potassium Compounds / Q000494:pharmacology; D000068098:Seed Bank; D036226:Seedlings / Q000254:growth & development*; D012639:Seeds / Q000502:physiology*; D013997:Time Factors
D005875:Gibberellins; D009566:Nitrates; D017680:Potassium Compounds; C023844:potassium nitrate