Developmental stability of Iris pumila flower traits: A common garden experiment

I. pumila natural populations usually occur in two different habitat types: dune and forest. These I. pumila habitats differ in many abiotic environmental factors, but mostly in available light intensity and quality. The effects of different light intensity on the developmental stability of I. pumila floral traits were analyzed on clones taken from two different natural light habitat types that were raised in contrasting light treatments in experimental garden conditions (common garden experiment). As an indicator of developmental stability, we used two fluctuating asymmetry indices (FA1 and FA8a) of three bilateral symmetric traits of I. pumila flower (FW-fall width, SW-standard width and STW- style branch width). In addition, statistically significant treatment x population interaction was observed for style width. According to the presented results, the observed FA patterns of particular traits did not reflect the whole organism buffering capacity under the given environmental conditions.Projekat ministarstva br. 17302

Morfometrijska i morfološka analiza lista crne topole (Populus nigra L.) u plavnim i neplavnim područjima sliva Dunava

Human activity induced global changes in nature, particularly the flooding regime, which is a stress factor affecting wetland ecosystems. Knowledge of plant strategies of wetland vegetation across a range of flooding gradients is therefore very important. Natural flooding events are increasing as a consequence of constant climate changes. This research was focused on the area of Special Nature Reserve “Gornje Podunavlje” which represents a complex of peculiar marshland, originating from former vast inundated parts of the Danube basin. We have selected samples located on both sides of the embankment in the defended and in the flooded area. The main aim is the assessment of Populus nigra L. riparian tree leaf morphological traits variability (centroid size, shape, developmental instability, specific leaf area and petiole lenght) between two habitats (flooded and not flooded). The geometric morphometry methods were applied to provide visual representation of differences in the leaf shape. We employed leaf composite index indices of fluctuating asymetry as a measure of developmental instability. A statistically ­significant impact of flooding was obtained only for the leaf geometric size and shape, so these traits could be an indicator of flooding as suboptimal environmental conditions.Ljudska aktivnost izazvala je globalne promjene u prirodi, posebice režim poplava, kao faktor stresa koji potencijalno utječe na močvarne ekosustave. Stoga je vrlo važno poznavanje strategija biljnog razvoja močvarne vegetacije na nizu poplavnih gradijenta. Učestale poplave su posljedica stalnih klimatskih promjena. Ovo istraživanje bilo je usmjereno na područje Specijalnog rezervata prirode “Gornje Podunavlje” koje predstavlja kompleks osebujnog močvarnog područja, koje potječe iz nekadašnjih prostranih poplavnih dijelova dunavskog bazena. Odabrali smo uzorke koji se nalaze s obje strane nasipa u branjenom području i u poplavljenom području. Glavni je cilj procena varijabilnosti morfologije lista Populus nigra L. (priobalna stabla) izmedju dva staništa (plavljeno i ne plavljeno). Metode geometrijske morfometrije primijenjene su kako bi se vizualno razlikovale oblike lista, dok smo kao mjeru razvojne nestabilnosti koristili kombinirane indeks listove fluktuirajuće asimetrije. Statistički značajan utjecaj poplava dobiven je samo za geometrijsku veličinu i oblik lista, te su ta svojstva prepoznata kao pokazatelji suboptimalnog sredinskog okruženja. Stoga je vrlo važno poznavanje strategija biljnog razvoja močvarne vegetacije na nizu poplavnih gradijenta

The influence of abiotic stressors on the development stability and morphological variability of Iris pumila in natural and experimental populations

Uticaj različitog inteziteta svetlosti, kao jednog od abiotičkih faktora životne sredine, na nivo stabilnosti razvića i morfološku varijabilnost osobina cveta I. pumila ispitivan je na jedinkama populacija koje naseljavaju dva prirodna staništa različitiog inteziteta i kvaliteta raspoložive svetlosti (otvoreno i zasenčeno stanište), kao i na jedinkama populacija poreklom sa otvorenog i zasenčenog staništa, koje su bile izložene tretmanima visokog i niskog svetlosnog inteziteta svetlosti u eksperimentalnim uslovima. Osnovna hipoteza je bila da pod uticajem suboptimalnog intenziteta svetlosti dolazi do smanjenja stabilnosti razvića cvetnih organa što se može utvrditi na osnovu stepena asimetrije radijalno i bilateralno simetričnih cvetnih organa. Stepen fluktuirajuće asimetrije i radijalne asimetrije kao mere nestabilnosti razvića jedinke ili populacije, zavisi od intenziteta delovanja biotičkih i abiotičkih stresora, a pošto je stepen asimetrije negativno korelisan sa stabilnošću razvića, a pozitivno sa razvojnim šumom, na osnovu toga treba očekivati veće vrednosti indeksa asimetrije, tj. veću nestabilnost razvića u stresnijim sredinskim uslovima. Veličina i obrazac stabilnosti razvića osobina cveta I.pumila su se razlikovali u zavisnosti od analizirane osobine, kao i od evolucione istorije istraživanih populacija. Prosečne vrednosti indeksa radijalne asimetrije su bile više u zasenčenom nego u otvorenom staništu, ukazujući da je zasenčeno stanište verovatno stresnija sredina. Populacije poreklom sa otvorenog i zasenčenog staništa su se razlikovale u srednjoj vrednosti indeksa radijalne asimetrije osobina cveta u okviru svakog od svetlosnih tretmana. Fluktuirajuća asimetrija, kao mera bilateralne simetrije osobina cveta I.pumila, imala je veće vrednosti u prirodnim staništima sa visokim svetlosnim intezitetom u poređenju sa niskim, na osnovu čega bi se moglo zaključiti da je otvoreno stanište stresnije za ovaj tip osobina cveta. Aktuelni svetlosni uslovi u alternativnim svetlosnim staništima su indukovali statistički značajne razlike u strukturi fenotipskih i genetičkih korelacionih matrica morfoloških osobina cveta I.pumila. Jaka korelativna veza između veličine fola i standarda na unutar-individualnom nivou u sredinama različitog svetlosnog inteziteta može da ukazuje na bliske veze procesa razvića pomenutih osobina.The main goal of thesis was to examine the influence of an abiotic environmental factor, such as light intensity, on the developmental stability level and morphological variability of I. pumila floral traits. The individuals, from natural habitat populations which located different light condition habitats (exposed and shaded one), as well as the individuals of populations derived from natural habitat but raised in experimental light conditions of low and high intensity, were used. The basic hypothesis was whether suboptimal light intensity decreased developmental stability of floral traits. Since the level of fluctuating and radial asymmetry is in negative correlation with developmental stability, but is positively correlated with developmental noise, the larger values of asymmetry index are to be expected in more stressful conditions. The developmental stability size and pattern of I. pumila floral traits differed depending on analyzed trait, as well as on the evolutionary history of analyzed populations. The radial asymmetry index showed higher average values in shaded habitat comparing to the exposed one, meaning that the exposed location is more stressful environment for development of the identical replicas of different floral organs. Populations derived from open and shaded habitat differed in an average value of radial asymmetry index of floral traits inside each light intensity treatments, but didn’t differ in fluctuating asymmetry level.Statistically significant interaction between treatment and population, that we got for the radial asymmetry of the standard length and all the indices of fluctuating asymmetry, indicate that the effect of the light intensity on the sensitivity of developmental stability of Iris pumila floral traits depends on the population origin: whether they originated from an open or a shaded habitat. The actual light regimes in different habitats create statistically significant differences in phenotypic and genetic correlation matrices’ structures of morphological Iris pumila floral traits. The correlation matrices of morphological Iris pumila floral traits coincided within and between populations derived from alternative light intensity treatments

Evolutionary biology studies on the Iris pumila clonal plant: Advantages of a good model system, main findings and directions for further research

Evolutionary studies on the dwarf bearded iris, Iris pumila L., a perennial clonal monocot with hermaphroditic enthomophylous flowers, have been conducted during the last three decades on plants and populations from the Deliblato Sands in Serbia. In this review we discuss the main advantages of this model system that have enabled various studies of several important genetic, ecological, and evolutionary issues at different levels of biological organization (molecular, physiological, anatomical, morphological and population). Based on published research and its resonance in international scientific literature, we present the main findings obtained from these studies, and discuss possible directions for further research

Developmental stability of Iris pumila flower traits: A common garden experiment

I. pumila natural populations usually occur in two different habitat types: dune and forest. These I. pumila habitats differ in many abiotic environmental factors, but mostly in available light intensity and quality. The effects of different light intensity on the developmental stability of I. pumila floral traits were analyzed on clones taken from two different natural light habitat types that were raised in contrasting light treatments in experimental garden conditions (common garden experiment). As an indicator of developmental stability, we used two fluctuating asymmetry indices (FA1 and FA8a) of three bilateral symmetric traits of I. pumila flower (FW-fall width, SW-standard width and STW- style branch width). In addition, statistically significant treatment x population interaction was observed for style width. According to the presented results, the observed FA patterns of particular traits did not reflect the whole organism buffering capacity under the given environmental conditions.Projekat ministarstva br. 17302

PROSTORNA I VREMENSKA VARIJABILNOST CVJETANJA HRASTA LUŽNJAKA (Quercus robur L.)

Climate change, as well as biotic and abiotic stress environmental factors and the exploitation of oak forests have the greatest impact in reducing the pedunculate oak areas. These factors on one side reduce the pedunculate oak living area, while on the other side they create unfavorable conditions for its renewal. In the last decades, there has been an attempt to change this situation, primarily by planting appropriate provenances and more resistant varieties. Knowledge of the phenological variability is one of the essential elements useful in separation of genotypes better adapted to changing environmental conditions.One of the phenological studies of the pedunculate oak implied the analysis of the pollination time as one of the intermediate phase of the flowering phenophase. Observations were carried out in two populations at two locations in the area of Belgrade (Serbia), "Ada Ciganlija" and "Bojčinska šuma", a total of 58 trees (29 trees per location) in three consecutive years (2004, 2005, 2006). According to the ANOVA results differences between locations and years were statistically significantly (all p <0.0001). Time of pollination in the location of "Bojčinska šuma" was earlier compared to location "Ada Ciganlija" in all three years of observation. The obtained time difference gives rise to the assumption that there are different varieties of the pedunculate oak: the "early" and the "late" one. According to the phenological pattern of population, the majority of trees maintain the same trend from year to year, i.e. remain in the same phenological group (labeled as "early", "average" and "late"), or change it for one phenological level, suggesting the genetic influence on the expression of this trait. Since those populations are located in similar environmental conditions, obtained differences between them can be regarded as a consequence of intraspecific variability of the pedunculate oak and of the genetic structure of population.U radu je analizirana individualna i populacijska varijabilnost polinacije kao međufaze fenofaze cvjetanja lužnjaka. Istraživanja su obavljena na 58 stabala u dvije populacije lužnjaka na dva lokaliteta na području Beograda (Srbija) tijekom tri uzastopne godine (2004, 2005, 2006). Populacije se nalaze u oblasti umjereno-kontinentalne klime, na staništima koja odgovaraju lužnjaku, mješovite su strukture, raznodobne, vegetativnog i sjemenog porjekla, starosti 60–120 g. Promatranje je vršeno jedanput tjedno u travnju/svibnju. Lužnjak na analiziranim lokalitetima, uzimajući u obzir sva stabla i godine promatranja, počinje cvjetati najranije 7. travnja a najkasnije 2. svibnja. Cvjetanje na lokalitetu "Bojčinska šuma" događa se oko tjedan dana ranije u odnosu na lokalitet "Ada Ciganlija". Statističkom obradom potvrđen je značajan učinak lokaliteta, godine i individue. Prema fenološkom obrascu populacija i podeli u odnosu na vrijeme cvjetanja, većina stabala na lokalitetu "Bojčinska šuma" pripada fenološkoj grupi "rani" lužnjak, a na lokalitetu "Ada Ciganlija" grupi "kasni" lužnjak. Tijekom godina promatranja, najveći broj stabala ostajao je u istoj fenološkoj grupi ili se mijenjao samo za jednu razinu. S obzirom da se populacije nalaze u sličnim sredinama i stanišnim uvjetima, dobivene razlike mogu se smatrati posljedicom unutarvrsne varijabilnosti lužnjaka i genetičke strukture populacije. Genetička stabilnost fenofaze cvjetanja korisna je u odabiru "ranih" i "kasnih" formi lužnjaka u procesu individualne selekcije pod utjecajem promjene klimatskih čimbenika

Pollen viability in Quercus robur L.

The variability of viability (germination rate and the length of pollen tubes) of fresh pedunculate oak (Quercus robur L.) pollen grains was studied in vitro on a medium containing 15% sucrose. Spatial variability was studied by sampling fresh pollen grains from a total of thirteen trees at four different sites in the area of Belgrade (Košutnjak, Banovo Brdo, Ada Ciganlija and Bojcin Forest) in a single year (2011). In order to assess temporal variability and determine the effects of climate change on a small time scale, we studied the viability of the pollen grains collected from one tree at the Banovo Brdo site in six different years (2004, 2005, 2006, 2007, 2011 and 2012). Interindividual variability was tested on the pollen grains sampled from eight trees at Ada Ciganlija in 2004. The percentage values of the pollen grain germination rate and the pollen tube length showed no statistically significant differences between the sites. However, the studied characteristics of the pollen grain viability (germination rate and pollen tube length) showed statistically significant differences in both temporal (between the pollen collection years) and interindividual variability. This type of research makes a valuable contribution to pedunculate oak breeding programs through the identification of trees with stable production and a good quality of pollen. Furthermore, it can be important in defining the patterns of spatial, temporal and individual variability of pollen grain viability under the influence of climate factors, which are showing compelling changing trends from year to year.Archives of Biological Sciences (2017), 69(1): 111-11

Length of vegetation period as parameter of common oak (Quercus robur L.) phenological variability

Paper presents results for length of vegetation period as factor in common oak’s (Quercus robur L.) phenological variability. Trees in two common oaks populations on two locations in area of Belgrade were researched. Average length of vegetation period on site Ada Ciganlija is 166 days, while in location Bojčinska šuma is 179 days. Regarding that populations are in similar environmental and habitual conditions, differences in results should be treated as consequence of common oaks intra-specific variability and genetic structure of population. Significant differences in three consecutive years of observation are confirmed.U radu su predstavljeni rezultati analize dužine trajanja vegetacije kao faktora fenološke varijabilnosti lužnjaka (Quercus robur L.). Istraživanja su obavljena na stablima u dve populacije lužnjaka na dva lokaliteta na području Beograda. Prosečno dužina trajanja vegetacije na lokalitetu Ada Ciganlija iznosi 166 dana a na lokalitetu Bojčinska šuma 179 dana. Obzirom da se populacije nalaze u sličnim sredinskim i stanišnim uslovima, dobijene razlike se mogu smatrati posledicom unutarvrsne varijabilnosti lužnjaka i genetičke strukture populacije. Potvrđene su značajne razlike između tri uzastopne godine osmatranja.Projekat ministarstva br. 4300

Inter and intra-population variation of leaf stomatal traits of Quercus robur L. in Northern Serbia

The research involved the examination of inter- and intra-population variation of stomatal traits: stomatal density, stomatal length and width, stomatal pore surface, potential conductance index and stomatal shape coefficient, in Quercus robur L. leaves. The research was conducted in northern Serbia and included five populations ('Ada Ciganlija', 'Bojčinska šuma', 'Subotica', 'Sombor' and 'Vršac'). The stomatal characteristics were examined in fully expanded leaves, from two leaf positions - the sun-exposed and shaded side of the tree. The leaf position in the tree crown, forming a part of the phenotypic variance, was relevant for the stomatal dimension traits. Within populations, the differences between the genotypes (i.e. trees), were relevant for all analyzed traits. On the basis of the analysis of the inter-populational differences, the 'Bojčinska šuma' population had a statistically significantly lower stomatal density in comparison to the other populations.Projekat ministarstva br. 33012 and 17302

The phenotypic plasticity of of Picea omorika /Panc./Purkyne morphological pollen traits

The variability of morphological traits of Picea omorika /Panč./Purkyne pollen was analyzed in two successive years on the pollen sampled from 24 trees in a seed stand at the site of Bela Zemlja in the area of Mt. Zlatibor (Serbia). The aim of the research was to obtain the index of phenotypic plasticity of the equatorial and polar axes and the coefficient of shape of pollen. According to the obtained results, Serbian spruce pollen grains are 93.3 μm/53.2 μm in size with their shape being oblate 57.5%. The climate characteristics of the study years initiated different responses of the pollen traits for each tree. Reaction norms were slightly steep and they crossed as confirmed by the significant interaction between the variability factors of the year and the tree. In the year with lower temperatures and less precipitation, the mean values of the equatorial axis were higher and the polar axis smaller, giving the pollen grain a more oblate form. According to the results of the applied model of analysis of variance where the year and the tree, as well as the interaction between them, were taken as factors of variability, the values of the pollen equatorial axis (length) and the coefficient of shape showed statistically significant differences between the years. Genetic variability (interindividual differences) for the values of both axes of pollen grains was confirmed by statistically significant differences between the trees in a single year. Interindividual differences in the observed morphological pollen traits were affected by environmental conditions specific to the year of sampling (statistically significant year x tree interaction). All the analyzed traits showed interindividual differences in the values of the plasticity index. The lowest values of plasticity were obtained for the equatorial axis (length) of the pollen grain, and they were significantly different from the plasticity indexes of the other traits analyzed herein. The plasticity of pollen traits has an important role in the controlled selection and breeding of species with the aim of obtaining more resistant genotypes with a greater ability to adapt to the fluctuations of environmental factors caused by global climate change