Introduzione e valorizzazione di rose siciliane autoctone a fini ornamentali
Author(s)
Fascella, Giancarlo
Date Issued
March 18, 2011
Type
Doctoral Thesis
Abstract
A study aimed to the localization, the introduction, the propagation and the cultivation of
Sicilian wild roses for ornamental uses was conducted during a three-year period. Their
potentialities were determined through the evaluation of some specific characteristics
(multiplicative, agronomic, eco-physiological) as well the aesthetic effect.
In 2008, seven autochthonous species were found in different areas of Sicily: Rosa canina
L., R. corymbifera Borkh, R. heckeliana Tratt., R. micrantha Borrer ex Sm, R. rubiginosa
L., R. sempervirens L., R. sicula Tratt. Regional distribution, natural habitats and biomorphological
features were described. Vegetative propagation (by cuttings) was also
tested using three rooting substrates (perlite, brown peat, perlite/peat 1:1, v/v) and two
naphtalen acetic acid concentrations (NAA, 0 and 4000 ppm).
In 2009, collected material was in vitro introduced through initial multiplication with four
benzyladenine levels (BA 0, 0.25, 0.5, 0.75 mg/L) and successive rooting by using three
indole acetic acid doses (IAA 0, 0.3, 0.6 mg/L). Seed propagation was also checked by
means of seeds that, after a 5-month cold storage, were sown directly or after physical
scarification with hot water for 30 or 60 seconds.
In 2010, plants derived from rooted cutting of R. canina e R. sempervirens were grown in
containers under drought stress by progressively reducing substrate water content (900,
600, 300 ml/plant) during irrigation; moreover, plants of R. sempervirens only were potcultivated
under salt stress by using irrigation water with increasing sodium chloride
content (NaCl 0, 40, 80 mM).
The present research showed that, among the studied accessions, R. canina resulted the
most diffused in the regional territory (found from 0 to 1500 m above sea level) followed
by R. sempervirens (from 100 to 800 m) which was the unique evergreen and reflowering
bush with a crawling trend; R. rubiginosa was the least common (over 1600 m only); R.
sicula evidenced the most compact habit as well as the shortest flowering period and ripe
fruits retention.
Higher rooting rates of cuttings (40.3%) were obtained with perlite/peat substrate and
NAA treatment; lower percentage (3.2%) were recorded on cuttings in brown peat and
with no auxin application; R. sempervirens cuttings showed the highest rooting rate
(32.6%), whereas those from R. rubiginosa the lowest values (0.8%).
Seed germination, as well as related parameters (mean germination time, number and
length of roots of seedlings), was not influenced by scarification treatments but only by
genotypes, with a high variability among species (from 98.6% in R. sempervirens to 0.2%
in R. heckeliana).
Micropropagation assay showed that in vitro multiplication phase was influenced by
genotype (R. canina was the most effective, three species were recalcitrant) and BA level:
rates increased (from 0.53 to 1.4 shoots/explant) according to the increase of hormone
concentration. In vitro rooting stage was also affected by genotype as well as IAA dose as
higher number of rooted plantlets was obtained with maximum auxin content for R. canina
(68.5%), and with the control for R. sempervirens (98.1%).
Trials of water deficit evidenced that higher stress level determined lower growth of
canopy and root of R. canina and R. sempervirens plants, as well reduced dry biomass
production and partitioning. Water stress negatively affected, by reducing average values,
plant water potential ( ) of both species (from -0.7 to -1.2 MPa) and main ecophysiological
activities (gas exchanges).
Salt stress experiment on R. sempervirens provided similar outcomes than those obtained
from drought trial as decreasing plant growth and biomass yield were recorded with the
increase of NaCl concentration in the irrigation water. Eco-physiological aspects were
partially influenced by the increasing salt content as some parameters (leaf relative water
content, stomatal conductance, transpiration) were significantly reduced, while others
(chlorophyll content, net photosynthesis) did not vary.
Additional information
Dottorato di ricerca in Ortoflorofrutticoltura
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