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The signals to trigger the initiation of ovule enlargement are from the pollen tubes: The direct evidence
Author(s) -
Zhong Sheng,
Zhang Jun,
Qu LiJia
Publication year - 2017
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/jipb.12577
Subject(s) - ovule , pollen tube , pollen , biology , pollination , sperm , human fertilization , botany , double fertilization , anatomy
Summary In angiosperms, initiation of ovule enlargement represents the start of seed development, the molecular mechanism of which is not yet elucidated. It was previously reported that pollen tube contents, rather than double fertilization, can trigger ovule enlargement. However, it remains unclear whether the signal(s) to trigger the initiation of ovule enlargement are from the sperm cells or from the pollen tubes. Recently, we identified a mutant drop1− drop2− , which produces pollen tubes with no sperm cells. Taking advantage of this special genetic material, we conducted pollination assays, and found that the ovules pollinated with drop1− drop2− pollen could initiate the enlargement and exhibited significant enlarged sizes at 36 h after pollination in comparison with those unpollinated ovules. However, the sizes of the ovules pollinated with drop1− drop2− pollen are significantly smaller than those of the ovules pollinated with wild‐type pollen. These results demonstrate that the pollen tube, rather than the sperm cells, release the signal to trigger the initiation of ovule enlargement, and that double fertilization is required for further enlargement of the seeds.