Adriana F. Sestras

Identification of Salt Stress Biomarkers in Romanian Carpathian Populations of Picea abies (L.) Karst.

The Norway spruce (Picea abies), the most important tree species in European forests, is relatively sensitive to salt and does not grow in natural saline environments. Yet many trees are actually exposed to salt stress due to the common practice of de-icing of mountain roads in winter, using large amounts of NaCl. To help develop strategies for an appropriate use of reproductive seed material on reforestation sites, ensuring better chances of seedling survival in salt-affected areas, we have studied the responses of young spruce seedlings to salt treatments. The specific aim of the work was to identify the optimal salt stress biomarkers in Picea abies, using as experimental material seedlings obtained by germination of seeds with origin in seven populations from the Romanian Carpathian Mountains. These responses included general, conserved reactions such as the accumulation of ions and different osmolytes in the seedlings needles, reduction in photosynthetic pigments levels, or activation of antioxidant systems. Although changes in the contents of different compounds involved in these reactions can be associated to the degree of stress affecting the plants, we propose that the (decreasing) levels of total phenolics or total carotenoids and the (increasing) levels of Na+ or K+ ions in Picea abies needles, should be considered as the most reliable and useful biomarkers for salt stress in this species. They all show very high correlation with the intensity of salt stress, independently of the genetic background of the seeds parental population, and relatively easy, quantitative assays are available to determine their concentrations, requiring simple equipment and little amount of plant material.

Screening for drought tolerance in cultivars of the ornamental genus Tagetes (Asteraceae)

Drought tolerance was evaluated in twelve cultivars of three ornamental Tagetes species (T. patula, T. tenuifolia and T. erecta). A stress treatment was performed by completely stopping watering of plants maintained in controlled greenhouse conditions. After three weeks, several plant growth parameters (stem length (SL), fresh weight (FW) and water content (WC)), photosynthetic pigments (chlorophylls and carotenoids (Car)), osmolytes (proline (Pro), glycine betaine (GB) and total soluble sugars (TSS)), an oxidative stress maker (malondialdehyde (MDA)) and antioxidants (total phenolic compounds (TPC) and total flavonoids (TF)) were measured. Considerable differences in the evaluated traits were found among the control and drought-stressed plants. Drought stress generally caused a marked reduction in plant growth and carotenoid pigments, and an increase in soluble solutes and oxidative stress. For most cultivars, proline levels in stressed plants increased between 30 and 70-fold compared to the corresponding controls. According to the different measured parameters, on average T. erecta proved to be more tolerant to drought than T. patula and T. tenuifolia. However, a considerable variation in the tolerance to drought was found within each species. The traits with greater association to drought tolerance as well as the most tolerant cultivars could be clearly identified in a principal components analysis (PCA). Overall, our results indicate that drought tolerant cultivars of Tagetes can be identified at early stages using a combination of plant growth and biochemical markers.

Biochemical responses to drought, at the seedling stage, of several Romanian Carpathian populations of Norway spruce (Picea abies L. Karst)

Key messageNorway spruce seedlings apparently showing a relatively higher tolerance to drought can be easily selected using a battery of biomarkers such as water content, chlorophyll, and proline levels in the needles, and could be eventually used as an initial screening method in reforestation programmes.AbstractNorway spruce is a native European coniferous species distributed from the Carpathian Mountains and the Alps to northern Scandinavia. In the coming decades, spruce forests will need to cope with increasing climate changes which are already threatening their natural habitats. To identify reliable water stress biomarkers in this species, which may be eventually used to select populations responding better to forecasted drought events, we studied the physiological responses to severe water stress treatments (6-week withholding irrigation in the greenhouse) of 1-year-old spruce seedlings originating from several locations in the Romanian Carpathian Mountains. Variations in the levels of the studied photosynthetic pigments, osmolytes, and non-enzymatic antioxidants were detected across the spruce populations. Several of the parameters determined in seedling needles, such as the decrease in water content (nearly 40% reduction in the most sensitive populations), the degradation of chlorophylls, or a low increase of proline levels (up to sevenfold increment in the most sensitive populations but no change in the most tolerant), could be employed as biomarkers for an early assessment of water stress at this stage. Furthermore, seedlings from two of the populations under study responded better to water stress than the other populations and also seemed to be the least affected by osmotic stress during seed germination. Therefore, the determination of these biochemical markers at early seedling stages could represent a useful tool for the initial screening of populations with relatively high tolerance to drought, warranting further research for their potential use in spruce reforestation programmes.

Molecular and flow cytometric evaluation of pear (Pyrus L.) genetic resources of the German and Romanian national fruit collections

A total of 188 German and 28 Romanian pear accessions were evaluated using flow cytometry and molecular markers to detect homonymous and synonymous genotypes, triploids, which are not useful for breeding, and genotypes having favorable traits for breeding. Genotyping was done using a set of 11 simple sequence repeat markers proposed by the European Cooperative Program for Plant Genetic Resources, along with a standard set of six reference pear genotypes used in previous studies. The observed number of alleles ranged between 21 and 38 per locus. Twenty-three accessions could be confirmed as triploids. Because of the expected cross-incompatibility they are only of limited interest for breeding. The study confirmed that 180 of the 188 tested German accessions represent unique genotypes, while some accessions were found to be genetically identical. In parallel additional markers, which are known to be linked to resistance/susceptibility to major pathogens (e.g. black spot, aphid, fire blight, and apple scab), were applied to the German accessions. The comparative screening of the Romanian pear genetic resources demonstrated that only a few accessions with identical/very similar names to German accessions really have an identical fingerprint. Mislabeling and homonymous designation of different genotypes seems to occur frequently in different collections.

Study of genitors influence on apple seeds germination within the cross combinations.

The studies regarding the germination of seeds obtained from 23 cross-combinations between different parental forms of apple, performed in the field of the Genetic and Breeding Department, of the Research Institute for Fruit Growing Pitesti, during 2006-2008 period, were conducted in the nursery. The seeds from the crossing programmes were extracted, washed in distilled water, dried and stored until December. After stratifications, the greatest number of seeds germinated from two combinations made in 2007: Rebra x DL 35 (97,72%) and Rebra x Goldrush (91,66%) and the least from three combinations made in 2006: Ardelean x Falstaff, Romus 5 x Dalinbel, Romus 4 x Goldrush. The studies regarding the genitors influence on the germination of apple hybrid seeds demonstrated a quite different potential in developing numerous hybrid progenies related to the parents involved, as well as to the value of various parental pairs.

THE VARIABILITY OF SOME CHARACTERISTICS OF THE BELL PEPPER CULTIVAR CIPRIAN (CAPSICUM ANNUUM L.)

The new bell pepper cultivar, created in 2007, is further cultured in conservative selection fields, in order to maintain biological authenticity and purity. Here we are presenting a brief study regarding the plant (height, diameter and the shape of the bush) and some features that determine productivity (number of fruits/plant, height, diameter and the mass of the fruits).

THE SEGREGATION OF TREE HABIT ON PEAR SEEDLINGS IN SIX HYBRID COMBINATIONS

Trees habit is an important trait in pear breeding and pear culture (1, 2, 3). The segregation for trees habit of F1 pear hybrids belonging from six combinations was analysed. The seedlings originate in incomplete diallel cross, effectuated with four genitors (Comtesse de Paris, Milenium, Virgiliu Hibernal, Cluj 89-1-81 selection), were framed in six classes of growth (after UPOV Guidelines), respectively architectural ideotype: 1. Fastigiate; 2. Upright; 3. Semi-upright; 4. Spreading; 5. Drooping; 6. Weeping. In each combination, the majority of F1 hybrids had spreading habit (between 57% in Comtesse de Paris x Milenium and 81% in Milenium x Cluj 89-1-81). The occurrence of high percentages of spreading habit seedlings in all combinations (see the table) suggests that this ideotype of tree growth is easy to obtain in pear breeding. Because a valuable type of tree habit for modern plantation is with a spurred growth habit and strong apical control, it can be appreciated that Milenium (a relative new cultivar created at Fruit Research Station Cluj-Napoca) can be used as genitor for this trait. Especially used as mother genitor in cross with Virgiliu Hibernal (another new cultivar obtained at FRS Cluj), Milenium gave birth to the highest percentage of upright seedlings (16%), and with fastigiate habit (3%)

THE INFLUENCE OF WATER TREATED BY PHYSICAL METHODS UPON THE GROWTH OF SOME DENDROLOGICAL SPECIES

In 2006, at Fruit Research Station Cluj were carri ed out experiments regarding the influence of water treated by some physical methods upon the growth of some dendrological varieties. The results of the study are presented i this poster. The experiments were made at the pot plants from Weigela florida “Variegata” and Thuja occidentalis “Smaragd” species and were used 3 variants of physical treat ed water in comparison with untreated water. During each wateri ng, it was used the same water quantity from each variant. The water variants used for watering, for both spe cies, were: V1untreated water; V2modified water by Ancu-Dinc ă effect; V3magnetized water with magnet, produced by Energet ix wi h magnetical field intensity of 1200 Gs; V4vibrated water. The experiment was organized in 4 repetitions, for 5 plants/repetition, for each species. The plants’ growth was monitored. At both species, it was found a positive influence, but insignificant in the case of watering with wate r modified by Ancu-Dincă effect and distinguishable positive influences in the case of watering with magnetised water. In conclusion: 1. Water magnetised by Energetix permanent magnet, by maintaining the water a certainn period of time in the magnetic field, stro ngly influences, positively, the growth of the Weigela florida „Variegata” and Thuja occidentalis „Smaragd” plants. 2. Water physically modified by Ancu-Dinc ă effect, also positively influences the growth of the two species, but in a less evident way (not significantly), and less economically.