Reduced pollen viability and achene development in Solidago ×niederederi Khek from Poland

Grzegorz Migdałek,Maria Kościńska-Pająk,Artur Pliszko,Jolanta Kolczyk,Aneta Słomka

doi:10.5586/asbp.2014.025

Abstract

Pollen and achene characters of natural interspecific hybrid Solidago ×niederederi Khek were analyzed and compared with putative parental species S. virgaurea L. and S. canadensis L. to estimate the level of disturbances in generative reproduction resulting from its hybrid nature. Pollen viability (stainability) of Solidago ×niederederi from one newly discovered locality in NE Poland was evidently reduced to ~65% in both viability tests (acetocarmine and Alexander). The diameter of viable pollen (median 21.11 µm) fell between S. canadensis (median 19.52 µm) and S. virgaurea (median 23.48 µm). Both parental species produced normally developed achenes with high frequency (~90%) whereas in the hybrid, the seed set was dramatically low (6%). The results clearly indicated that sexual reproduction of hybridogenous taxon S. ×niederederi is disturbed, and its potential impact as an invasive species depends mainly on vegetative propagation.

Highlights

The phenomenon of plant hybridization between alien species and their native congeners that support biotic homogenization significantly reflects global changes in native floras
In Europe, Solidago ×niederederi Khek, a natural hybrid between the alien S. canadensis L. and the native S. virgaurea L. [3,4,5] has rarely been recorded in Austria, Denmark, Sweden, Norway, the United Kingdom, Germany, and in Poland [3,4,5,6,7,8,9,10,11,12,13]
S. canadensis and S. virgaurea, which belong to different sections – Unilaterales and Solidago, respectively

Summary

Introduction

The phenomenon of plant hybridization between alien species and their native congeners that support biotic homogenization significantly reflects global changes in native floras. Its occurrence is undoubtedly an indirect result of naturalization and invasion of North American S. canadensis [14,15] It is usually intermediate in the shape of inflorescence, the size of the capitulum, and the shape and venation of its leaf [4,5]. It has either restricted fertility, able to produce only a few well-developed achenes [4], or Handling Editor: Beata Zagórska-Marek is completely sterile [6]. Solidago ×niederederi grows in open disturbed areas (e.g., abandoned arable fields, quarries, clay pits, railway and river embankments), usually together with the parental species [4,5,6,7,8,9,10,11,12]

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