The changes in endogenous proline levels of Raphanus sativus L. seedlings was monitored in presence of exogenous amino acids in normal and osmotically stressed seedlings. In unstressed seedlings, proline uptake was detected only at higher (1 mM) concentration of applied L-proline. however, proline uptake was promoted at all (1 µM to 1000 µM) concentrations of applied L-proline under osmotic stress conditions. Amongst other exogenous amino acids, L-leucine, L-glutamic acid, L-alanine, and L-histidine enhanced endogenous levels of proline, while exogenous hydorxyproline and γ-amino butyric acid reduced it.
The use of high quality sowing material is the fundamental condition for good yielding of crop plants. One of new, unconventional methods of seed quality improvement is low-frequency variable magnetic field. It has been found that this physical factor has a favourable effect on seed germination, emergence and growth of many crop plants. The objective of the study was to determine the effect of low-frequency magnetic field (LFMF) on the germination of radish seeds, with particular emphasis on old seeds. The experimental material were seeds of 7 lots of radish cv. ‘Mila’, with germination capacity of 66.5–92.5%. The age of the seeds was from 1 to 8 years. Seeds from all the lots were treated with variable magnetic field with frequency of 50 Hz, at 3 doses of magnetic induction as follows: 0 (control), 30 and 60 mT for 30 seconds. Then, the seed germination energy and capacity were determined, as well as the length of the hypocotyl and of the radicle of the seedling, dry weight of seedling, and emergence and mean time of emergence. The low frequency magnetic field exposure (30 and 60 mT) improved radish seed germination energy and capacity of every old seed lot. The increase of germination energy of old seeds amounted to 12.3–19.2%, and the increase of germination capacity was 5.8–10%. Magnetic field stimulation caused the increase of germination energy for 3 out of 4 seed lots of high quality but did not affect the improvement of germination capacity of those lots. No significant effect of magnetic field of seeds on the hypocotyl and radicle elongation was observed with the exception of 1 out of the 7 seed lots. For the 2 old seed lots out of the 3 total, magnetic field treatment caused the increase of emergence by 4.4–13.0%.
NADP-isocitrate dehydrogenase (NADP-ICDH) activity of radish (Raphanus sativus L.) seedlings pretreated with various plant growth regulators: KiN, GA, and ABA and different nitrogen sources viz. KNO₃, NH₄Cl and NH₄NO₃ in light and dark was investigated. ICDH activity was significantly higher in light than in dark; addition of different nitrogen sources reduced it to a greater extent in NO₃ supplementation. Among hormonal treatment only KiN showed slight promotion with KNO₃ and NH₄NO₃. On the other hand in light KNO₃ and/or NH₄NO₃ promoted ICDH activity and among hormones, KiN significantly promoted the activity in KNO₃ and NH₄NO₃ supplemented seedlings while ABA was effective in NH₄CL. It is suggested that in non-photosynthetic tissues, NADP-ICDH provides both reductant and carbon skeleton for glutamate synthesis.
Intergeneric hybrids between non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino; 2n = 4x = 40) and radish (Raphanus sativus L.; 2n = 4x = 36) were obtained through ovary culture and embryo rescue. Some hybrid embryos (0.11 per ovary) were produced, but only 4 of them germinated. As most hybrid embryos failed to develop into plantlets directly, plants were regenerated by inducing shoots on the cultured cotyledon and inducing roots on the root induction medium. All hybrid plants were morphologically uniform. They resembled the non-heading Chinese cabbage in the long-lived habit, the plant status, the vernalization requirement and the petiole color, while the petiole shape, leaf venation pattern and flowers were more similar to those of radish. Upon examination of the flowers, these were found to have normal pistil, but rudimentary anthers with non-functional pollen grains. The somatic chromosome number of F1 plants was 38. Analysis of SSR banding patterns provided additional confirmation of hybridity.
Changes in the thiocyanate content in hypocotyl-roots and leaves of radish were observed in a two-year field experiment. Six cultivars were tested: early radish (Rex and Ostergruss Różowa), Japanese radish (Tokinashi and Minowase Summer Cross F₁), and winter radish (Monachijska Biała and Murzynka). A significant diversification in thiocyanate content among cultivars, plant parts, harvest dates and observation years was found. Early cultivars contained the least amount of these compounds, Murzynka — the greatest. The content of thiocyanates in leaves was 3 – 5 times higher than that in hypocotyl-roots. The changes in the thiocyanate content during root growth showed a constant rising tendency in the case of the leaves of all cultivars and the storage organs of Murzynka.
An approach which could be used for quick searches for RAPD markers is described for groups of radish lines with certain morphological traits. The lines are characterized by various morpho-physiological abnormalities, including tumor formation (lines 12, 19, and 21) and non-terminal development of the flower meristem as a variant of tumor growth (line 6). We found four markers which differentiate tumor radish lines 12, 19, and 21 from the others, and two which differentiate line 6.
Relationships between radish thiocyanate content and its dry weight, the content of sugar, protein, fibre, ascorbic acid, some minerals, the incidence of plant shooting, the firmness and pithiness of storage-roots, and the ratio of leaves to storageroot (wt/wt) were investigated. The analysis of linear correlation was based on numerous data from the 4-year field experiment with six radish cultivars and different sowing and harvest dates. The content of thiocyanate in radish roots was found to be positively correlated with their dry weight, and the content of total protein, crude fibre, and soluble sugar. A strong relationship was found between the content of thiocyanate and dry weight of radish leaves. The negative correlation between the thiocyanate content in the leaves and the firmness of storageroots and the positive correlation with their pithiness might indicate the translocation of this compounds into green plant parts during the ageing of root tissue. The root thiocyanate content and the percentage of shooting correlated significantly only in the case of Tokinashi. The closeness of relations between the ratio of leaves/storage-root and thiocyanate content, though in general small, was affected also by a cultivar. A similar effect was observed for the correlations between the thiocyanate contents in leaves and storage-roots.