Chlorophyll in desiccated seeds of a euhalophyte, Suaeda physophora, and its significancy in plant adaptation to salinity during germination.

The seed cotyledons of a euhalophyte, Suaeda physophora, were found to be dark green. The pigment extracted from the cotyledons was proved to be chlorophyll for the absorption spectra curve of extracts the same as that for leaves. Photosynthetic oxygen-exchanging could be detected after the seeds were moistened for 6 h. Microstructure of organelles in cotyledons of ungerminated seeds was detected by transmission electron microscopy. Histochemical pigmentation was used to investigate the degree of damage on the membrane of radicles. A xerophyte, Haloxylon persicum, whose cotyledons of desiccated seeds also contain chlorophyll was used as a comparative species. The results showed that S. physophora maintained the ultra-structure of chloroplasts, the integrity of plasma membranes of radicles kept much better than that of H. persicum, which showed the great adaptability to salinity of the euhalophyte even at the seed-germination stage. Seeds were incubated in 0 and 700 mmol/L NaCl for 10 days in darkness at 20 degrees C, then ungerminated seeds in NaCl solution were transferred to deionised water and reincubated for another 8 days and was recorded the germination recovery. Dry seeds moistened with deionised water germinated gradually in the dark and germination was maximal after 3 or 4 d. Seeds at 700 mmol/L NaCl for 10 d and transferred back to deionised water germinated abruptly, most seeds germinated in one day and photosynthesis was also detected. It is concluded that recovery germination of S. physophora ensured the seeds could germinate rapidly after salinity declines, for example under the mild but transitory favorable edaphic condition in early spring. Photosynthesis function in seeds might also promoted radicle growth and seedling establishment.

Germination of dimorphic seeds of the desert annual halophyte Suaeda aralocaspica (Chenopodiaceae), a C4 plant without Kranz anatomy.

BACKGROUND AND AIMS: Suaeda aralocaspica is a C4 summer annual halophyte without Kranz anatomy that is restricted to the deserts of central Asia. It produces two distinct types of seeds that differ in colour, shape and size. The primary aims of the present study were to compare the dormancy and germination characteristics of dimorphic seeds of S. aralocaspica and to develop a conceptual model of their dynamics. METHODS: Temperatures simulating those in the natural habitat of S. aralocaspica were used to test for primary dormancy and germination behaviour of fresh brown and black seeds. The effects of cold stratification, gibberellic acid, seed coat scarification, seed coat removal and dry storage on dormancy breaking were tested in black seeds. Germination percentage and recovery responses of brown seeds, non-treated black seeds and 8-week cold-stratified black seeds to salt stress were tested. KEY RESULTS: Brown seeds were non-dormant, whereas black seeds had non-deep Type 2 physiological dormancy (PD). Germination percentage and rate of germination of brown seeds and of variously pretreated black seeds were significantly higher than those of non-pretreated black seeds. Exposure of seeds to various salinities had significant effects on germination, germination recovery and induction into secondary dormancy. A conceptual model is presented that ties these results together and puts them into an ecological context. CONCLUSIONS: The two seed morphs of S. aralocaspica exhibit distinct differences in dormancy and germination characteristics. Suaeda aralocaspica is the first cold desert halophyte for which non-deep Type 2 PD has been documented.

Row distance method sowing of forage Kochia, eastern saltwort and winterfat.

In this study, we used three native range species of eastern saltwort, winterfat and forage Kochia. These species are extremely adapted to dry lands and have high productivity comparison with other forage species. In order to increase range production in poor, dry and sub dry land in the province of Khorasan (Sabzevar) the seeds of these species naturally were sowed. They were sowed individually on rows and mixed of the two by 2 or 3 species on the alternative rows. The research was carried out statistically in Completely Randomized Block Design (CRBD) as a factorial experiment by two factors. The first factor was row distance of seeding (three levels, 50, 75 and 100 cm distance between each row) and the second was kinds of intercropping methods (seven level of individual seeding by three mentioned species and mixed alternative rows of two by 2 and 3 species together) with four replicates (3x7x4). Number of seed was accounted by the number of bushes were germinated or died in each experimental unit. The results showed that maximum abundant of seed germination of all treatments was occurred from late April to late May. Sowing in the row spaces of 50 cm had highly statistically significant production than the ones of 75 and 100 cm spaces. Also, by comparing relative frequency percentage of germinated seeds and relative germinated died seed revealed that individual sowing seed of Salsola orientalis and Eurotia ceratoides, by 50 cm row space in Sabzevar region had better result, respectively, because of lowest mortality of plants and highest productivity of biomass.

Seed protein variations of Salicornia L. and allied taxa in Turkey.

Electrophoretic seed protein patterns of a number of accessions of Salicornia europaea L. sl., S. prostrata Palas, S. fragilis P.W. Ball and Tutin, Sarcocornia fruticosa (L.) A. J. Scott, Sarcocornia perennis (Miller.) A. J. Scott, Arthrocnemum glaucum (Del.) Ung.-Sternb., Microcnemum coralloides (Loscos and Pardo) subsp. anatolicum Wagenitz and Halocnemum strobilaceum (Pall.) Bieb. were electrophoretically analysed on SDS-PAGE. In total 48 different bands were identified. The obtained data have been treated numerically using the cluster analysis method of unweighted pair group (UPGMA). Finally it was determined that all species separated according to seed protein profiles. And the cladogram obtained studied taxa have been given.

[Bacterial microflora on disinfected sugar beets]. / Bakterail'naia mikroflora protravlennykh semian sakharnoi svekly.

Sugar beet seeds disinfected with the carbofuran-containing insecticide adifur and the fungicide tachygaren by seed-producing firms were found to be abundantly populated with bacterial microflora. The bacteria isolated from the seed surface were identified to a species level. The selection of bacteria with respect to pesticide resistance may lead to the obtaining of agronomically useful bacterial strains.