prilagođeno pretraživanje po punom tekstu

ŠUMARSKI LIST 7-8/2014 str. 28     <-- 28 -->        PDF

wild cherry plus trees has been started according to natural distribution of the species and information about seed sources. On this occasion, totally 58 genotypes, from five localities were described. Geographical coordinates of plus trees were determined and stored in the database together with information about stem straightness, branching, diameter, height and vitality of trees (Pilipović et al. 2011). Similar activities were continued in the following years, as well. During 2011, seeds of 61 genotypes from 12 localities in Serbia, were collected and sown in seedbeds for the purposes of establishing of progeny test. These tests has an important role in plant breeding, because it provides useful information, both, about the properties of the progeny tested and parent trees.
Variations in net photosynthesis and related gas exchange parameters have been reported as determinants of plant productivity. Researches of numerous authors showed that research of these parameters can provide useful information about growth potential of genotype and plant productivity (Kundu & Tigerstedt 1998; Orlović et al. 2001; Orlović et al. 2006). For example, investigating the relationships between growth and leaf-scale physiological parameters in five WildstarTM cherry clones, Stokes and Kerr (2006) reported that varieties with high net photosynthesis tended to have good height increment and relative growth rate, while those with low net photosynthesis, transpiration and stomatal conductance had poor height increment. Similarly, discussing about possibility of use of physiological traits in tree breeding for improved yield in drought-prone environments, Pita et al. (2005) highlighted the relevance of stomatal conductance and water use efficiency, as well as hydraulic traits.
This paper presents study on the variability of leaf photosyntetic traits of five Serbian wild cherry families, assessed in a nursery trial. The objectives of the study were to: 1) estimate the magnitude of the family variability in gas exchange parameters and 2) to determine the physiological parameters which has the highest discriminatory capacity.
Materijali i metode
The trial is situated in the nursery of the Institute of Lowland Forestry and Environment, which is located at the territory of Experimental Estate "Kaćka šuma" in Kać (N 45°17´; E 19°53´). The site is at 76 m altitude with temperate continental climate. Mean annual temperature is 11.1°C and annual precipitation sum of 624 mm. During the vegetation period (April-September) mean air temperature is 17.8°C and the sum of precipitations amounts 369 mm. The climate records are from the weather station Rimski Sancevi (N 45°20´, E 19°51´; 84 m a.s.l). Temperature and precipitation have been averaged for the time period between 1966–2004.
Study involved five families of wild cherry (Prunus avium L.) originating from Northern part of Serbia (Figure 1). Details of the families used in trial are given in Table 1.
Seed used for the establishing of progeny trial was collected separately from each plus tree during the vegetation period of 2011 and sown in seedbeds during October of the same year. Measurements were carried out in August 2012 at the one year old seedlings.
Net photosynthesis (A, μmol m–2 s–1), transpiration (E, mmol m–2 s–1) and stomatal conductance (gs, mol m–2 s–1) were recorded by using ADC Bioscientific Ltd. LCPro+ portable gas analysis system, on 10 plants from each family, in five replications per single plant. Measurements were made on fully expanded leaves, between 09:00 and 11:00 hours a.m., on days with clear and sunny weather. Photosynthetic active radiation (PAR) has been set to volume of 1000 μmol m–2 s–1, while the temperature, humidity and the concentration of CO2 in the device’s chamber were set to ambient. The ratio of net photosynthesis (A) to transpiration (E) was calculated to determine water use efficiency (WUE, μmol mmol−1) (Zhang et al. 2004).
Statistical analyses were conducted by using software Statistica 10 (StatSoft, Inc.). Descriptive statistics and one-way