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ROLE OF CALCIUM IN THE CALLOSE RESPONSE OF SELF‐POLLINATED BRASSICA STIGMAS
Author(s) -
Singh Anuradha,
Paolillo Dominick J.
Publication year - 1990
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1990.tb13536.x
Subject(s) - callose , pollen , pollen tube , biology , gynoecium , botany , calcium , pollination , cell wall , chemistry , stamen , organic chemistry
In Brassica oleracea , sporophytic self‐incompatibility prevents germination of self pollen, or normal growth of self pollen tubes. After self‐pollination, the papillae of stigmas synthesize callose. The role of Ca ++ in the formation of stigmatic callose was tested by adding compounds that interact with Ca ++ to suspensions of pollen that were known to induce callose formation in self stigmas. The calcium channel antagonist, lanthanum, and the calcium chelating agent, EGTA, reduced or abolished the callose response to self‐pollen suspensions. In the presence of Ca ++ , the calcium ionophore, A23187, induced callose in stigmatic papillae when added to pollen suspensions, or alone. Therefore, callose deposition in response to incompatible pollinations appears to be a calcium‐dependent process. Pretreatment of pistils with 100 μ m 2‐deoxy‐D‐glucose abolished the callose response to self‐pollination, while self pollen remained inhibited and cross pollen grew normally in treated pistils. Thus, callose formation in the stigma is not an essential part of the self‐incompatibility mechanism preventing the growth of self pollen in Brassica.