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Seed dormancy in Avena fatua : Interacting effects of nitrate, water and seed coat injury
Author(s) -
Mclntyre G. I.,
Cessna A. J.,
Hsiao A. I.
Publication year - 1996
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1996.970212.x
Subject(s) - caryopsis , germination , avena fatua , potassium nitrate , dormancy , osmotic pressure , seed dormancy , nitrate , agronomy , horticulture , ammonium nitrate , chemistry , biology , botany , potassium , ecology , organic chemistry
In experiments conducted under controlled conditions. KNO 3 (50 or 100 m M ) promoted germination of a dormant strain (AN 474) of Avena fatua when either one or two holes were pierced in the lower (adaxial) surface of the caryopsis in contact with the nitrate solution. Germination was increased by increasing either the KNO 3 concentration or the number of holes in the seed coat. The germination response induced by the application of water to a hole pierced in the upper surface of the caryopsis was. increased by pre‐treatment of the intact caryopsis with KNO 3 . Treatment with either 50 or 100 m M KNO 3 caused a transient reduction in embryo water content of intact cary‐opses, but increased the nitrate and amino‐ N content of pierced caryopses prior to germination. Supplying a 100 m M solution of KNO 3 to pierced caryopses reduced the total water potential and osmotic potential of the embryo, and increased its pressure potential by the same amount as an equimolar solution of KC1; however, while both treatments promoted germination, the KNO 3 induced more rapid germination than the KCI. Both treatments also increased the K + content of the embryo, the KNO 3 again having the greater effect. These results are consistent with the hypothesis, based on our previous investigations, that KNO 3 promotes germination of dormant caryopses by accumulating in the embryo where it acts osmotically to increase water uptake. It is also postulated, that, in contrast to KCI, KNG 3 may combine an osmotic effect on water uptake with a nutritional effect on protein synthesis.