Differences in Morphological, Physiological and Growth Traits between Two Endemic Subspecies of Brassica rupestris Raf.: Implications for Their Conservation

Maria Fiore Crescente, Loretta Gratani

Department of Environmental Biology, Sapienza University of Rome, Rome, Italy..

DOI: 10.4236/ajps.2013.46A007                

Abstract

The goal of this work was to analyze the phenological and physiological responses of Brassica rupestris Raf. subsp. hispida Raimondo & Mazzola and Brassica rupestris Raf. subsp. rupestris to environmental factors also in consideration of global change. We used seedlings of the two subspecies originated from wild plants from the natural habitats in Sicily and cultivated in the Botanical Garden of Rome. Leaf morphological and physiological traits and growth dynamic were analyzed as well as the response to an imposed water stress experiment. The results underlined a higher relative growth rate in plant height (RGR_H, cm·cm^-1·d^-1) in B. rupestris subsp. rupestris also attested by the highest plant height (H, cm), leaf area (LA, cm²), specific leaf area (SLA, cm·g^-1), total leaf area per plant (TLA, cm²) and total plant dry mass (PDM, g plant^-1). Moreover, the significantly highest net photosynthetic rates (A, μmol CO₂ m^-2·s^-1) during the study period of this subspecies was related to the high Chlorophyll content (Chl, SPAD units). B. rupestris subsp. rupestris was also the most tolerant subspecies to imposed water stress showing the highest relative water content (RWC, %), A and water use efficiency (WUE, μmol·mmol^-1).

Keywords

Brassica rupestris Raf. subsp. hispida Raimondo & Mazzola; Brassica rupestris Raf. subsp. rupestris; Conservation; Drought Stress; Endemism; Global Change; Growth Analysis; Physiological Traits; Red-Listed Species

Conflicts of Interest

The authors declare no conflicts of interest.

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