Key message

This research revealed diverse PTG rates among intraspecific pollen–pistil interactions that showed variable dependency on the stigma and mature TT.

Abstract

Pollen–pistil interactions regulate pollen tube growth (PTG) rates and are determinants of fertilization and seed set. This research focuses on the diversity of intraspecific PTG rates and the spatial and temporal regulation of PTG among Nicotiana tabacum genotypes. Nonrandom mating within self-compatible species has been noted, but little is known on the mechanisms involved. To begin research on nonrandom mating, we took advantage of the model reproductive system of N. tabacum and used seventeen diverse N. tabacum genotypes in a complete pollination diallel to measure the diversity of intraspecific pollen–pistil interactions. The 289 intraspecific interactions showed surprisingly large differences in PTG rates. The interaction between specific males and females resulted in 18 specific combining abilities that were significantly different, indicating the importance of the specific genotype interaction in regulating intraspecific PTG. No single female or male genotype exerted overall control of PTG rates, as determined by a general combining ability analysis. Slow and fast pollen–pistil interactions showed spatial differences in growth rates along the style. Slower interactions had a slower initial PTG rate while fast interactions had faster consistent rates of growth indicating spatial regulation of PTG in the pistil. Removal of the stigma or the mature transmitting tissue (TT) showed the tissue-specific component of PTG regulation. Stigma removal resulted in slower or no change in PTG rate depending on the pollen and pistil genotypes. Removal of the TT, which necessitated removal of the stigma, showed no change, slower or unexpectedly, increased growth rates relative to growth rates without a stigma. These data show the diverse nature of pollen–pistil interactions in N. tabacum genotypes providing a system to further investigate the regulation of PTG.

中文翻译：

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烟草花粉-雌蕊相互作用显示基因型之间花粉管生长的意想不到的时空差异。

关键信息

这项研究揭示了种内花粉-雌蕊相互作用中不同的PTG速率，表明它们对柱头和成熟TT的依赖性不同。

抽象

花粉与雌蕊的相互作用调节花粉管的生长（PTG）速率，是受精和结实的决定因素。本研究侧重于烟草基因型中种内PTG速率的多样性和PTG的时空调控。人们已经注意到自相容物种内的非随机交配，但对涉及的机制知之甚少。为了开始非随机交配的研究，我们利用了烟草的模型繁殖系统，并使用了十七种不同的烟草完整授粉花粉中的基因型，以测量种内花粉-雌蕊相互作用的多样性。289种种内相互作用显示出令人惊讶的PTG速率差异。特定雄性和雌性之间的相互作用导致18种特异性结合能力显着不同，表明特异性基因型相互作用在调节种内PTG方面的重要性。如通过一般结合能力分析所确定的，没有一个女性或男性基因型能完全控制PTG的发生率。花粉-雌蕊缓慢和快速的相互作用显示出沿花型生长速率的空间差异。较慢的相互作用具有较慢的初始PTG速率，而较快的相互作用具有较快的一致生长速率，表明雌蕊PTG的空间调节。去除柱头或成熟的传输组织（TT）显示了PTG调节的组织特异性成分。根据花粉和雌蕊的基因型，去除柱头导致PTG速率变慢或没有变化。去除TT（需要去除柱头）相对于没有柱头的增长率没有显示出变化（较慢或出乎意料）。这些数据表明花粉-雌蕊相互作用的多样性烟草的基因型为进一步研究PTG的调控提供了系统。