Effects of genotype and stigma development stage on seed set following intra- and inter-specific hybridization of Dianthus spp.
Effects of genotype and stigma development stage on seed set following intra- and inter-specific hybridization of Dianthus spp.
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DOI：
10.1016/j.scienta.2011.02.021
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发表时间：
2011-05
影响因子：
4.3
通讯作者：
Xiaopeng Fu;Jingjing Zhang;Feng Li;PinTing Zhan;M. Bao
中科院分区：
文献类型：
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作者：
Xiaopeng Fu;Jingjing Zhang;Feng Li;PinTing Zhan;M. Bao
康乃馨科是开花植物的一个家族，通常被称为粉红色或康乃馨家族。该科的成员作为观赏植物广泛种植。种石竹（Dianthus chinensis）、石竹（Dianthus vegetatus）和石竹（Dianthus superbus）包括这种观赏品种的显著实例。种内和种间杂交对于改良品种的育种是重要的，因此，期望优化该家族内异花授粉程序的效率。在这里，我们进行了种内授粉使用四个线的D。chinensis之间的种间授粉; chinensis，中国拟步行虫D. tuberatus和D. superbus基因型对于这些杂交，我们记录的花粉生活力，柱头发育阶段在授粉时，花粉萌发的柱头表面和花粉管伸长的柱头内，最终结实的信息。花粉活力水平在花药开裂开始时测定，花药开裂发生在开花的第1天。D.中国变种'Bz2'，D.红腹原变种'Xb'和D. Superbus野生种'Qm'均表现出良好的花粉生活力水平（即在68%和75%之间）;中国茶“H58 III”、“H68 I”和“H6 II”显示出较低水平的花粉生活力（即在32%和51%之间）。在开花后1- 7 d内，观察到每个石竹品系柱头器官的形态变化。我们将这些变化描述为五个不同的发育阶段，即“柱状”（第1天）、“Y形”（第2天）、“Y形轻微弯曲”（第3-4天）、“Y形角状”（第5-6天）和“萎蔫”（第7天）。在每个发育阶段人工将花粉施加到柱头器官上，苯胺蓝染色用于跟踪花粉管在柱头表面的萌发和花粉管沿柱头长度的伸长。这说明柱头“Y形微弯”时期（3-4d）是授粉的最佳时期。“Y形角状”期（5-6d）也是授粉的敏感期。相比之下，早期的“Y形”（2d）和“柱”（1d）阶段，以及后期的“萎蔫”（7 d）阶段，接受性要差得多。进行了平行的田间试验，其中在不同发育阶段的花的人工授粉后测量结实率。这些数据还表明，授粉的最佳时间是在花开放的3-4d。这一结论适用于各种石竹系的种内和种间杂交。因此，石竹柱头可授性在开花后3-4d才达到最佳状态。由于花药开裂发生在1d（即柱头处于不接受的“柱”阶段），这表明石竹采用延迟自花受精策略。我们还发现，基因型对花粉管生长和结实值的显着影响。每花种子数最高的是D.种间杂交的母本为木荷野生种Qm。因此，基因型和柱头发育被确定为决定石竹系异花授粉成功的关键因素。
The caryophyllaceae is a family of flowering plants commonly known as the pink or carnation family. Members of this family are widely grown as ornamental plants. The species Dianthus chinensis, Dianthus barbatus, and Dianthus superbus include notable examples of such ornamental varieties. Intra- and inter-specific hybridization is important for the breeding of improved varieties and, therefore, it is desirable to optimize the efficiency of cross-pollination procedures within this family. Here, we conducted intra-specific pollination using four lines of D. chinensis, and inter-specific pollination between D. chinensis, D. barbatus and D. superbus genotypes. For each of these crosses we recorded information of pollen viability, stigma development stage at time of pollination, pollen germination on the stigma surface and pollen tube elongation within the stigma, and final seed set. Pollen viability levels were determined at the start of anther dehiscence, which occurred on day 1 of flower opening. The genotypes D. chinensis var. ‘Bz2’, D. barbatus var. ‘Xb’, and D. superbus wild species ‘Qm’ all displayed good levels of pollen viability (i.e. between 68% and 75%); D. chinensis vars. ‘H58III’, ‘H68I’ and ‘H6II’ showed lower levels of pollen viability (i.e. between 32% and 51%). In each Dianthus line, the stigma organs were observed to undergo morphological changes during the 1–7d following flower opening. We have characterized these changes as five distinct development stages, namely, ‘column’ (day 1), ‘Y-like’ (day 2), ‘Y-shaped with slight curve’ (days 3–4), ‘Y-shaped horn-like’ (days 5–6), and ‘wilting’ (day 7). Pollen was artificially applied to stigma organs at each of these development stages and aniline blue staining was used to follow pollen tube germination on the stigma surface and pollen tube elongation down the length of the stigma. This showed that the ‘Y-shaped slightly curved’ stigma stage (3–4d) was optimal for pollination. The ‘Y-shaped horn-like’ stage (5–6d) was also receptive to pollination. By contrast, the earlier ‘Y-shaped’ (2d) and ‘column’ (1d) stages, and also the later ‘wilting’ (7d) stage, were far less receptive. Parallel field experiments were conducted in which seed set was measured following the artificial pollination of flowers at different development stages. These data also indicated that the optimal time for pollination was during 3–4d of flower opening. This conclusion held true for both intra- and inter-specific crosses of the various Dianthus lines. Thus, stigma receptivity in Dianthus does not become optimal until 3–4d after flower opening. Since anther dehiscence occurs at 1d (i.e. when stigma are at the unreceptive ‘column’ stage), this suggests that Dianthus employs a delayed self-fertilization strategy. We also found a significant effect of genotype on pollen tube growth and seed-set values. The highest numbers of seed per flower were achieved when the D. superbus wild species ‘Qm’ was the female parent in inter-specific crosses. Thus, genotype and stigma development are identified as key factors that determine the success of cross-pollination in Dianthus lines.