Light germinator

The increased germination was not the direct effect of pH alone or of the one particular buffer. Phthalate-HCl, glycine-HCl, and sodium aconitate buffers at pH 3.2 had no effect in the dark but did increase the sensitivity of seed to light. Germination in darkness occurred only when the acid or a buffered solution of gibberellin was used to moisten the substrate. 

Flax seeds were placed for germination on moist paper for three days at 22°C and in the dark then, the plantlets were transferred under continuous white light on a liquid culture medium, as previously described [6], Suspension-cultured cells of flax were obtained from hypocotyl-derived calli as described by Schaumann et al. [4] and cultured on a medium described by Murashige and Skoog [7] containing kinetin (0.75 mg 1 ) and 2-4 D (0.2 mg 1 ). 

Allen CD, Ansel KM, Low C, et al. Germinal center dark and light zone organization is mediated by CXCR4 and CXCR5. Nat Immunol 2004 5 943-952. 

Carolina in 1981. Each sample (1.4 ml of methanolic sample) was placed into a 3-cm petri dish and the solvent evaporated under a laminar flow hood at room temperature. Seventy seeds (0.035 g) were then placed into the petri dishes and 1.4 ml of sterilized (0.2 pm-filter) 15 mM Mes [2-(N-morpholino)ethanesulfonic acid Sigma Chemical Co.] buffer adjusted to pH 5.5 was added. The dishes were kept in the dark at 25°C2for 84 hr, exposed to 12-hr fluorescent light (250 p einsteins/m /sec), and then placed back in the dark for an additional 4 days (17). Percent germination, root and hypocotyl lengths were then determined. 

Five-g samples of wheat plant material were soaked in 150 ml of water for 10 hr at room temperature. The mixture was filtered and the filtrate used to germinate pitted morningglory (Ipomoea lacunosa L.) and ragweed (Ambrosia artemisiifolia L.) seed. The effect of the extract on germination was tested in the presence and absence of light. 

Table IX. Effect of Light on Morningglory and Ragweed Germination with Aqueous Wheat Extract...

Vegetative microspores of Cryptogams are unicellular objects with hard cover, blue-fluorescence in ultra-violet light and elaters [serve as anchor to a substrate (soil)]. The cells are diploid and have autotrophic nutrition due to the presence of chloroplasts, where photosynthesis occurs. They germinate well in artificial nutrient medium or in water and ultra-violet light induces significant autofluorescence. 

Fig. 1 Vegetative microspores of horsetail Equisetum arvense. Left - Dry spore with elaters fluoresce under UV light (360-380 nm) Right - Germinated spore without elaters. The blue-fluorescing cover is missed.

Procedure Pollen develops on the nutrition medium, forming pollen tube (Fig. 3). The nutrient medium for pollen was 10% sucrose solution and tested compounds were also dissolved in 10% sucrose. The pollen develops till the formation of pollen tube that lasts from 2-3 h (fresh collected and one week stored pollen) to 24 h (stored > 1 week, but < 1.5-2 months). All experiments were done at room temperature 20-22 °C. The growth occurred in the solution studied (0.05 ml = 1 drop) on the slides (object glasses) put on wet paper in Petri dishes. Five ml of water was added to the bottom of every dish and 4-5 dishes with the slides were used per treatment. Using light microscope, we determined the microspores germination (%) 2-24 h after moistening. The number of developed pollen tubes was counted. 

Krupa, J. (1964). Studies on the physiology of germination of spores of Funaria hygrometrica (Sibth.). I. The influence of light on germination with respect to water balance and respiratory processes. Acta Societatis Botanicorum Poloniae 33 177-192. 

Procedure Germination conditions were 25 1°C under continuous fluorescent light of 25 mE m 2 sec-1. Seed germination was monitored by observing the seeds directly in the Petri dishes with a stereomicroscope. They were considered germinated, when the radicle had protruded through the seed coat. Seeds sampled at different times after the beginning of imbibition were used for microscopy studies. 

Procedure Purslane seeds were collected from crop fields near Naples. Five hundred seeds were sown in 10 Petri dishes (0 =90 mm), containing 5 layers of Whatman filter paper impregnated with 7 ml of water (control) or 7 ml rue infusion/chromatographic fractions or isolated compounds as per treatment. Thereafter, daily 3 ml water was added to each Petri plate. Germination conditions were 30 1°C with a continuous light of 25 4,E/m2/... 

Protocol updated from Krolak et al. (49) and Dashek and Mills (50). Controls (a) Germinate pollen without [14C]-pro and process as before, (b) Construct a radioautographic sandwich with collodion lacking pollen, (c) Expose a slide coated with Kodak NTB-2 Nuclear Track Emulsion to light and develop emulsion with D-19. (Sample autoradiographs are presented in Fig. 3.)... 

Teasdale JR, Mohler CL (1993) Light transmittance soil temperature, and soil moisture under residue of hairy vetch and rye. Agronomy J 85 673-680 Teasdale JR, Mohler CL (2000) The quantitative relationship between weed emergence and the physical properties of mulches. Weed Sci 48 385-392 Teasdale JR, Pillai P (2005) Contribution of ammonium to stimulation of smooth pigweed germination by extracts of hairy vetch residue. Weed Biol Manag 5 19-25 Teasdale JR, Beste CE, Potts WE (1991) Response of weeds to tillage and cover crop residue. Weed Sci 39 195-199... 

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