Effects of ovular secretions of pollen in Pseudotsuga menziesii (Pinaceae)
Effects of ovular secretions on pollen grains were examined in Pseudotsuga menziesii. The exine is cast off in the micropylar canal. A membranelike structure covers parts of pollen grains and appears to protect them. The outer intine consists of fibrous materials, but it also shows a thicker filamen...
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Published in | American journal of botany Vol. 81; no. 4 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
01.04.1994
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Subjects | |
Online Access | Get more information |
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Summary: | Effects of ovular secretions on pollen grains were examined in Pseudotsuga menziesii. The exine is cast off in the micropylar canal. A membranelike structure covers parts of pollen grains and appears to protect them. The outer intine consists of fibrous materials, but it also shows a thicker filamentous appearance in some ovules during pollen elongation. The inner intine is electron-dense. Its fibrous nature is occasionally visible. Dissolution of the outer intine varies in amount and manner in ovules from different trees. The plasma membrane near the pollen wall alternatively appears normal and distorted. These different morphologies of the outer intine and of the plasma membrane are considered to result from secretions from the ovule. The outer intine may contain electron-dense globules that are formed in the tube cell and traverse the inner intine. Pollen tube formation appears to be triggered by a secretion from the ovule. Cross-pollinated grains are less distorted compared with self-pollinated grains |
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Bibliography: | 9529500 K01 F63 |
ISSN: | 0002-9122 1537-2197 |
DOI: | 10.1002/j.1537-2197.1994.tb15475.x |