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Dive into the research topics where M. A. Lo Gullo is active.

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Featured researches published by M. A. Lo Gullo.


Biologia Plantarum | 2002

Changes in stem and leaf hydraulics preceding leaf shedding in Castanea sativa L.

Sebastiano Salleo; Andrea Nardini; M. A. Lo Gullo; L.A. Ghirardelli

This paper describes changes in leaf water status and in stem, petiole and leaf blade hydraulics preceding leaf senescence and shedding in Castanea sativa L. (chestnut). Measurements of maximum diurnal leaf conductance to water vapour (gL), minimum water potential (ψL), hydraulic conductance per unit leaf surface area of stems (KSL), petioles (KPL) and leaf blades (KLL) and number of functional conduits and inside diameter distribution were performed in June, September and October 1999. In September, still green leaves had undergone some dehydration as indicated by decreased gL (by 75 %) and ψL with respect to June. In the same time, KSL decreased by 88 %, while KPL and KLL decreased by 50 % and 20 % of the conduits of stems and 10 % of the petioles (all belonging to the widest diameter range) were no longer functioning, causing a decrease in the theoretical flow by 82 % in stems and 27 % in petioles. Stem xylem blockage was apparently due to tyloses growing into conduits. We advance the hypothesis that the entire process of leaf shedding and winter rest may be initiated by extensive stem embolism occurring during the summer.


Plant and Soil | 2003

Drought resistance of 2-year-old saplings of Mediterranean forest trees in the field: relations between water relations, hydraulics and productivity

M. A. Lo Gullo; Sebastiano Salleo; Rosa Rosso; Patrizia Trifilò

Drought resistance was examined for 2-year-old saplings of Ceratonia siliqua L., Olea oleaster Hoffmgg. et Link., Quercus suber L. and Q. pubescens Willd. growing in the field in Sicily, with the aim of testing their possible use in the reforestation of degraded areas. To this purpose, leaf conductance to water vapour (gL), transpiration rate (EL), relative water content (RWC) and water potential (ΨL) were measured between pre-dawn and sunset, monthly from May to November. Parallel measurements of loss of hydraulic conductance of twigs of the current year (PLC) were made together with an estimate of whole-plant hydraulic conductance (KPLANT) on the basis of the ratio of maximum EL to (ΨPD-ΨMIN), where ΨPD is pre-dawn ΨL and ΨMIN is the minimum diurnal ΨL. C. siliqua saplings maintained high gL throughout the study period with high RWC (over 90%) and ΨL. They grew rapidly and increased their foliage area (AL) by over 60% from May to winter rest. This was accompanied by low twig PLC (about 20% in September) resulting in high KPLANT all through the study period. In contrast, O. oleaster saplings underwent distinct dehydration in July, i.e. they showed stomatal closure due to a drop in RWC (to 75%) and ΨL (to the turgor-loss point). This was apparently due to twig cavitation, resulting in a strong decrease of KPLANT. Plants, however, tolerated summer drought, and showed growth (AL increased by 15% from May to November). Saplings of Q. suber and Q. pubescens were much more vulnerable to twig cavitation (PLC was 35–48% from June to November) than the other two species, and their average KPLANT was lower. Saplings of Q. suber and Q. pubescens grew only during the wet spring period, and no new foliage was produced thereafter. Changes in twig hydraulic conductance played a dominant role in determining changes in KPLANT in that the two variables were well correlated to each other (r=0.68 for P=0.001). We conclude that C. siliqua is an ideal candidate for reforestation of Sicilian degraded areas as is O. oleaster that, however, requires some additional water supply in the summer, at least during the early years after plantation. In wetter locations of Sicily, to an altitude between 0 and 500 m, Q. suber and Q. pubescens can be used for reforestation with expected higher competitiveness of the latter over the former species.


Plant Biosystems | 1998

Root hydraulic conductance of six forest trees: possible adaptive significance of seasonal changes

Andrea Nardini; S. Salleo; M. A. Lo Gullo

ABSTRACT Root hydraulic conductance (KR was measured in terms of the ratio of volume flow through roots (F) and to the pressure (P) driving the flow in six forest trees growing in habitats characterized by different water availabilities Le. Acer campestre L., Castanea sativa Miller, Fraxinus ornus L., Fraxinus oxycarpa Bieb., Ceratonia siliqua L. and Olea oleaster Hoffmg. et Link. Measurements were made in May, August and November 1996. KR as normalized for unit leaf surface area (KRL), was higher in species growing in humid environments (A. campestre and C. sativa) than in others (C. siliqua and O. oleaster) typical of aria zones. A. campestre and C. sativa showed declining KRL values from spring to autumn while the latter had highest KRL values in summer. This is in agreement with the typical drought avoidance strategy of C. siliqua which is based on large water losses balanced by equal water uptake from the soil. Plots of F and of A (leaf surface area) to KRL as well as annual percent changes in F, AL ...


Annals of Botany | 2012

Mistletoes and mutant albino shoots on woody plants as mineral nutrient traps

M. A. Lo Gullo; G. Glatzel; M. Devkota; Fabio Raimondo; Patrizia Trifilò; Hanno Richter

Background and Aims Potassium, sulphur and zinc contents of mistletoe leaves are generally higher than in their hosts. This is attributed to the fact that chemical elements which are cycled between xylem and phloem in the process of phloem loading of sugars are trapped in the mistletoe, because these parasites do not feed their hosts. Here it is hypothesized that mutant albino shoots on otherwise green plants should behave similarly, because they lack photosynthesis and thus cannot recycle elements involved in sugar loading. Methods The mineral nutrition of the mistletoe Scurrula elata was compared with that of albino shoots on Citrus sinensis and Nerium oleander. The potential for selective nutrient uptake by the mistletoe was studied by comparing element contents of host leaves on infected and uninfected branches and by manipulation of the haustorium–shoot ratio in mistletoes. Phloem anatomy of albino leaves was compared with that of green leaves. Key Results Both mistletoes and albino leaves had higher contents of potassium, sulphur and zinc than hosts or green leaves, respectively. Hypothetical discrimination of nutrient elements during the uptake by the haustorium is not supported by our data. Anatomical studies of albino leaves showed characteristics of release phloem. Conclusions Both albino shoots and mistletoes are traps for elements normally recycled between xylem and phloem, because retranslocation of phloem mobile elements into the mother plant or the host is low or absent. It can be assumed that the lack of photosynthetic activity in albino shoots and thus of sugars needed in phloem loading is responsible for the accumulation of elements. The absence of phloem loading is reflected in phloem anatomy of these abnormal shoots. In mistletoes the evolution of a parasitic lifestyle has obviously eliminated substantial feeding of the host with photosynthates produced by the mistletoe.


Plant Biosystems | 1990

Wood anatomy of some trees with diffuse- and ring-porous wood : some functional and ecological interpretations

M. A. Lo Gullo; S. Salleo

Abstract The xylem conduit dimensions (i.e. their width and length) have been measured in 1-year-old internodes, nodes and node-to-petiole (N-P) junctions of three species with diffuse-porous wood, namely Ceratonia siliqua L., Laurus nobilis L. and Olea europaea L. as well as of three species with ring-porous wood, namely Quercus ilex L., Q. suber L. and Q. pubescens Willd‥ The xylem conduit diameter and length distributions have been related to the drought resistance strategies adopted by the six species. C. siliqua and Q. ilex (drought avoiding water spenders) showed the widest xylem conduits (each species within its characteristic pattern of wood anatomy). This is consistent with their high demand of efficient water transport to leaves. L. nobilis (drought avoiding water saver) showed relatively narrow xylem conduits, efficient enough, however, to assure water supply to leaves at the reduced transpiration rate exhibited by the species. O. europaea, Q. suber and Q. pubescens (drought tolerants) showed t...


Marine and Freshwater Research | 2014

Multidisciplinary ecological assessment of the Alcantara River (Sicily, Italy) using bioindicators

L. Guglielmo; F. Azzaro; C. Baviera; A. Bergamasco; Spencer N. Bissett; C. Brugnano; G. Caruso; F. Decembrini; A. L. Garey; A. Granata; C. Gugliandolo; V. Lentini; M. A. Lo Gullo; T. L. Maugeri; M. Pansera; Fabio Raimondo; L. P. Rodriguez Valdes; L. A. Smock; A. Spanò; Patrizia Trifilò; Jaclyn K. Vick; Donald R. Young; G. Zagami; Julie C. Zinnert; R. Minutoli

This study was developed within the framework of a broad international project, ‘Ecological water quality assessment of the Alcantara (Italy), James (USA) and Guadalfeo (Spain) rivers using bioindicators’, established by the Center for Integrative Mediterranean Studies (CIMS), a collaborative research centre consisting of the University of Messina – Italy, Virginia Commonwealth University – USA, and the University of Cordoba – Spain. The primary objective of the study was the validation of a multi-disciplinary ecological approach at different taxonomic levels for biomonitoring of the Alcantara River (Sicily, Italy) using bioindicators. This study examined the primary physical, chemical and biological features of the river through an interdisciplinary and synoptic approach using bioindicators that included riparian plant physiology, the microbial, zooplanktonic and macroinvertebrate assemblages, Coleoptera (Insecta) and river hydrology. Sampling of the river and riparian areas was conducted at sites from the river’s headwaters to the mouth. The study provided information on the ecological status of the Alcantara River along its course and tested the use of a variety of bioindicators, rather than a single biotic or physicalattribute, to determine the river’s health.


Plant Biosystems | 1997

Xylem embolization by the pressure collar in Salix viminalis L.: sites for embolization and ultrasound acoustic emission

M. A. Lo Gullo; S. Zhang; S. B. Kikuta; Hanno Richter

ABSTRACT Pressurized air (3.5 MPa) produced massive embolization and loss of hydraulic conductivity in detached willow twigs (Salix viminalis L.) enclosed in a pressure collar. A state of tension in the xylem water column was not a necessary precondition for this embolization. Ultrasound acoustic emissions on the distal side and close to the collar were recorded only when air-saturated water was leaving the collar, whether moved by transpiration or by an overpressure applied to a reservoir at the base of the twig. Water released from embolized xylem elements increased the water potential of the leaves. The results show that air entry into xylem elements inside the pressure collar is the main mechanism responsible for the loss of hydraulic conductivity with the pressure collar technique, and that ultrasound signals originating within the collar are not sensed on the outside.


New Phytologist | 1988

Different strategies of drought resistance in three Mediterranean sclerophyllous trees growing in the same environmental conditions

M. A. Lo Gullo; S. Salleo


Plant Cell and Environment | 1993

Different vulnerabilities of Quercus ilex L. to freeze- and summer drought-induced xylem embolism: an ecological interpretation

M. A. Lo Gullo; S. Salleo


Annals of Botany | 1990

Sclerophylly and Plant Water Relations in Three Mediterranean Quercus Species

S. Salleo; M. A. Lo Gullo

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S. Salleo

University of Messina

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Hanno Richter

University of Agricultural Sciences

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S. B. Kikuta

University of Agricultural Sciences

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A. Spanò

University of Messina

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