EFFECT OF HYPOXIA ON BURIED WEED SEED GERMINATION

Summary Trials were carried out in order to investigate the effect of hypoxia on seed germination of Datura stramonium L. in Petri dishes and when buried at various depths in soil. Hypoxia was found to cause a decrease in germination capacity and germination rate. This inhibition was partially alleviated by daily exchange of hypoxic gas surrounding the seeds during incubation. Similarly, seed scarification allowed maintenance of a higher germination capacity under conditions of low oxygen availability, showing that the seed coat was only partially gas permeable. Oxygen deficiency led to a decrease in respiratory capacity. However, this was probably compensated for by induction of fermentation metabolism. The possibility of removing the final products of fermentation exerts a decisive influence on seed germination, especially in an environment such as soil, where their diffusion into the surrounding environment is restricted. Thus daily nitrogen flushing partially eliminated this inhibition, even under conditions of low external oxygen availability. It was therefore postulated that the main depth–derived inhibition was not caused directly by oxygen deficiency but by the increasing difficulty in eliminating toxic fermentation products, which was found to be proportional to the degree of hypoxia. Finally, incubation for several days under completely anaerobic conditions induced secondary dormancy. This was probably due to an ecological adaptation mechanism that prevents germination under conditions that are unfavourable for survival.

[1]  C. C. Black,et al.  Growth, partitioning, and harvest index of tuber-bearing solanum genotypes grown in two contrasting peruvian environments. , 1986, Plant physiology.

[2]  L. Stolzy,et al.  Plant Responses to Oxygen Supply and Physical Resistance in the Root Environment1 , 1966 .

[3]  P. Perata,et al.  Plant responses to anaerobiosis , 1993 .

[4]  P. Wareing,et al.  The Role of Light in the Germination of Naturally Occurring Populations of Buried Weed Seeds , 1969 .

[5]  E. Schweizer,et al.  Weed Seed Decline in Irrigated Soil after Six Years of Continuous Corn (Zea mays) and Herbicides , 1984, Weed Science.

[6]  R. Crawford,et al.  Tolerance of Anoxia and Ethanol Toxicity in Chickpea seedlings (Cicer arietinum L.) , 1984 .

[7]  D. Mandoli,et al.  Some spectral properties of several soil types: implications for photomorphogenesis* , 1990 .

[8]  L. Wax,et al.  An Index Model for Predicting Seed Germination and Emergence Rates , 1993, Weed Technology.

[9]  R. Kennedy,et al.  Anaerobic Metabolism in Germinating Seeds of Echinochloa crus-galli (Barnyard Grass) : METABOLITE AND ENZYME STUDIES. , 1981, Plant physiology.

[10]  W. Hurtt,et al.  Chemical manipulation of weed emergence , 1986 .

[11]  J. Kigel,et al.  Short soaking in water inhibits germination of Datura ferox L. and D. stramonium L. seeds , 1989 .

[12]  C. M. Karssen,et al.  Environmental factors influencing the expression of dormancy patterns in weed seeds. , 1989 .

[13]  P. Perata,et al.  Ethanol-induced injuries to carrot cells : the role of acetaldehyde. , 1991, Plant physiology.

[14]  M. Zhang,et al.  Evolution of volatile compounds by seeds during storage periods , 1993 .

[15]  R. H. Callihan,et al.  Longevity of Yellow Starthistle (Centaurea solstitialis) Achenes in Soil , 1993, Weed Technology.

[16]  H. Yoshikawa,et al.  VARIATION IN THE PHOTOCHEMICAL REACTIVITY OF THYMINE IN THE DNA OF B. SUBTILIS SPORES, VEGETATIVE CELLS AND SPORES GERMINATED IN CHLORAMPHENICOL*,† , 1966, Photochemistry and photobiology.

[17]  Eric D. Kerr,et al.  Potential for Using Weed Seed Content in the Soil to Predict Future Weed Problems , 1985, Weed Science.

[18]  C. Baskin,et al.  Role of temperature in regulating timing of germination in soil seed reserves of Thlaspi arvense L. , 1989 .

[19]  F. Forcella,et al.  Prediction of weed seedling densities from buried seed reserves , 1992 .

[20]  Harry Smith,et al.  Penetration of light into soil and its role in the control of seed germination , 1985 .

[21]  B. R. Somerhalder,et al.  Effect of Seedbed Preparation for Corn on Distribution of Weed Seed , 1971, Weed Science.

[22]  H. A. Roberts,et al.  Emergence patterns of weed seedlings in relation to cultivation and rainfall , 1980 .

[23]  C. Ballaré,et al.  PHOTOMORPHOGENIC PROCESSES IN THE AGRICULTURAL ENVIRONMENT , 1992 .

[24]  C. M. Karssen,et al.  Changes in dormancy of Sisymbrium officinale seeds do not depend on changes in respiratory activity , 1993 .

[25]  P. Perata,et al.  Ethanol metabolism in suspension cultured carrot cells , 1991 .

[26]  D. Mandoli,et al.  Phytochrome control of two low-irradiance responses in etiolated oat seedlings. , 1981, Plant physiology.

[27]  C. Baskin,et al.  The Annual Dormancy Cycle in Buried Weed Seeds: A Continuum , 1985 .

[28]  F. Corbineau,et al.  Interrelated effects of temperature, light and oxygen on Amaranthus caudatus L. seed germination , 1992 .

[29]  M. Tester,et al.  The penetration of light through soil , 1987 .

[30]  G. Barralis.  EVOLUTION COMPARATIVE DE LA FLORE ADVENTICE AVEC OU SANS DESHERBAGE CHIMIQUE , 1972 .

[31]  R. Bellinder,et al.  Comparisons of HOE-39866, SC-0224, Paraquat, and Glyphosate in No-Till Corn (Zea mays) , 1985, Weed Science.

[32]  A. Pradet,et al.  Germination, respiration, and adenylate energy charge of seeds at various oxygen partial pressures. , 1985, Plant physiology.

[33]  G. Hendrỳ.  Oxygen, free radical processes and seed longevity , 1993, Seed Science Research.

[34]  R. E. Holm.  Volatile metabolites controlling germination in buried weed seeds. , 1972, Plant physiology.

[35]  M. A. Warwick.  Buried seeds in arable soils in Scotland , 1984 .

[36]  M. Evenari,et al.  Integumentary Mucilage as an Oxygen Barrier During Germination of Blepharis persica (Burm.) Kuntze , 1969, Botanical Gazette.

[37]  H. A. Roberts,et al.  CHANGES IN THE NUMBERS OF VIABLE WEED SEEDS IN SOIL UNDER DIFFERENT REGIMES , 1973 .

[38]  A. F. Wiese,et al.  The Effects of Temperature and Rainfall on Emergence and Growth of Eight Weeds , 1985, Weed Science.

[39]  Y. Esashi,et al.  A mechanism of seed deterioration in relation to the volatile compounds evolved by dry seeds themselves , 1994, Seed Science Research.

[40]  M. Jackson,et al.  An examination of the importance of ethanol in causing injury to flooded plants , 1982 .

[41]  M. K. Upadhyaya,et al.  Seed Germination Ecophysiology of Meadow Salsify (Tragopogon pratensis) and Western Salsify (T. dubius) , 1993, Weed Science.