Radish seeds

The rate of germination of white clover seed was stimulated by 100 pM ferullc acid through the Initial 24 hr of the test (Table II). Germination of clover was delayed by 500 pM ferullc acid, but after 36 hr no differences were observed at 100 to 500 UM concentrations. High concentrations (1000-2000 pM) were consistently inhibitory. Radish seed germination was not affected by ferullc acid levels tested except at 24 hr when those In 500 PM were less than controls. 

TABLE II. Effect of Ferullc Acid (FA) on the Germination of White Clover and Radish Seed... 

Five ml aliquots of leachate or extract were pipetted onto 3 sheets of germination paper in a petri dish. Twenty five tomato or radish seeds were placed in each dish. Each treatment/seed combination was replicated five times. The assays were incubated at 20°C radish roots length was measured at 96 hrs and tomato at 168 hrs. 

Root elongation bloassay of root exudates. Five ml aliquots of the root exudates were pipetted onto three layers of Anchor1 germination paper In a 10 by 10 by 1.5 cm plastic petri dish. Twenty five radish or tomato seeds were placed in a 5x5 array in each petri dish. Radish seeds were incubated at 20C for 96 hours tomato seeds were incubated at 20C for 168 hours, before the root length was measured. Experimental design was a completely randomized design with three replications (dishes) per treatment per bioassay seed species. The bioassay was repeated each week for 23 weeks. 

O Donoghue K., Clapham A., Evershed R.P., Brown T.A. Remarkable preservation of biomo lecules in ancient radish seeds, Proceedings of the Royal Society London B, 1996,263,541 547. 

Rue infusion was tested for its allelopathic activity in vitro on water uptake and germination of radish seeds. Seeds of radish (Raphanus sativus L.) Saxa, collected during 2003, were purchased from Improta Co., Naples. 

Experiment 1. To determine the water uptake of radish seeds... 

Procedure Ten radish seeds (80 5 mg) were sown in each Petri dish (9-cm diameter) on three layers of filter paper (Whatman No. 3) previously moistened either with 7 ml of distilled water (control) or 7 ml of rue infusion (treated). Eighteen hours after sowing, control and rue treated radish seeds were differently moistened, having weight increases of 110 and 80 % respectively. The water uptake was evaluated as the difference in weight between moist and dry seeds (% of initial weight)(Fig.l.). 

Fig. 1 Water uptake by radish seeds in presence (o) and absence ( ) of rue extract (on a percent of initial weight of seeds).

Figure 2 reports the time dependent germination pattern of radish seeds in the presence and absence of rue extract. Although the germination curves have the same general shape, important differences between control and treated seeds are evident. In fact, the rue extract induces a delay in the onset and a decrease in the rate of germination. 

By means of stereo, light and electron microscopy, we have studied the anatomical and ultrastructural aspects of hilum-micropylar region of the radish seed, where the radicle protrudes. 

I. Stereomicroscopy of radish seeds The studies were carried out after 18 h in the presence and absence of rue extract, when most of the seeds soaked in water were germinating. Treated seeds were dormant, and the different uptake of water into these seeds was evident. 

II. Scanning electron microscopy of radish seeds For scanning electron microscopy (SEM) observations, seed coats and endosperms were fixed in 3% glutaraldehyde in 0.065 M phosphate buffer (pH 7.4) for 2 h at... 

Fig. 4 Graphic showing the structural features of a seed coat and endosperm of a radish seed, according to Vaughan and Whitehouse (1971). e, epidermis p, palisade pi, pigment layer al, aleurone layer hi, hyalin layer. 

III. Transmission electron microscopy of radish seeds Transmission electron microscopy (TEM) of radish seeds was done as listed below For TEM preparations, the specimens after fixation and dehydration, were embedded in Epon 812 resin (Luft, 1961). Thick sections (ca. 1mm each) were stained with 0.1% toluidine blue and observed with a Zeiss light photomicroscope. Thin sections, obtained with a diamond knife on a Supernova microtome, were sequentially stained at room temperature with 2% uranyle acetate (aqueous) for 5 min and by lead citrate for 10 min (Reynolds, 1963). Ultrastructural studies were made using a Philips CM12 transmission electrone microscope (TEM) operated at 80 KV. 

Based on the results from radish seeds, we also studied the influence of the rue extract on germination of purslane. Purslane is a major weed worldwide of 45 crops in 81 countries. The ploughable layer of the soil cropped with maize contains about 220,000 purslane seed per m2. Purslane fruit is a capsule with a pyxidium and a caliptra containing 50-70 black seeds (Holm etal.,1977). 

Aliotta, G., Cafiero, G., De Feo, V. and Sacchi, R. (1994). Potential allelochemicals from Ruta graveolens L. and their action on radish seeds. Journal of Chemical Ecology 20 2761-2775. 

The germination experiments (in quadmplicate) were carried out on filter paper in peril dishes. The corresponding water extracts (5 mL) (1/10) from the sewage sludge or soils were introduced into the dishes, with distilled water as the control in other dishes. Twenty-five radish seeds Raphanus sativus) were then placed on the filter paper and the dishes placed in a germination chamber maintained at 20°C. The root lengths were measured after three days. 

Soil microcosms with radish seeds planted on top... 

Radish seeds were treated with RO fraction at dilutions 1 8, 1 10 and 1 14 as described above and were processed for electron microscopy 46 h after the start of the treatment. Roots from control seeds, moistened with distilled water, were fixed after 2, 16 and 46 h in order to get several developmental stages as references for treated seeds. The root apex, about 1 mm long, was cut under a dissecting microscope from at least 10 seeds and fixed in the primary fixative for 2 h at room temperature under mild vacuum. Since the control seeds had not yet started germination after 2 h imbibition and nearly 100% of the seeds treated with 1 8-diluted had not germinated after 46 h, in these two cases the seed integument was cut open with a razor blade in order to dissect the root. 

Seed germination and seedling growth of radish in petri dishes were designed to evaluate the phytotoxicity of OMW fractions, thirteen polyphenols isolated from RO fraction and a mixture of these compounds. Radish seed (Raphanus sativus L. cv Saxa), collected during 1999, were purchased from Improta Co., Naples. To test the inhibitory effect of OMW fractions and RO, 20 seeds of radish were placed on two layers of filter paper (Whatman No. 1) in Petri dishes (90 mm diameter). The paper was wetted with 4 mL of buffered distilled water (BDW) with MES (2-N-[morpholino]ethanesulfonic acid) 10 mM, or test solution (undiluted fraction and a series of dilutions 1 2, one part of fraction to two parts of DW, 1 6 1 8 1 10 and 1 14). All pH values were adjusted to 6.0 before bioassay with MES. Experiments were made in triplicate. 

Other plants harmonize because they mature at different times. Radish and carrot seeds are often sown together the larger radish seeds mark the row as you plant, and the quick-emerging radish seedlings hold the soil against rain for the slower-growing carrots. You ll harvest the radishes long before the carrots need the space to fatten. 

Caryophyllene comprises almost 20Z of the Identified hydrocarbons. The steam volatiles of L. nodlflora also contain the monoterpenes 8-plnene and -cyrnene which Asplund (Ref.55) found Inhibitory toward radish seed germination. These terpenes may well be acting as allelochemlcals In nodlflora. contributing to Its ability to grow rampantly and to Inhibit lettuce seedling growth. 

Radish seeds were incubated in Petri dishes on filter paper with 10 ml solutions of 0, 2.5 UM, 0.25 UM and. 025 pJ ... 

Radish seeds Raphonus sativus L. cv national, Vilmorin,... 

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