Root Formation in Deteriorated (Aged) Wheat Embryos

Abstract

Inability of aged seeds to grow into successful plants in the field is primarily due to their age-associated loss of rooting ability. The present work describes an attempt to initiate roots in nonrooting aged embryos of wheat (Triticum aestivum L.). Data presented give a comparative study of root formation and seedling growth on different culture media. Such studies indicate that sucrose alone is enough to bring about root development in nonrooting aged embryos.The ability of nutrient media to achieve improved growth of isolated immature and mature embryos has often been reported in the literature. Excised barley embryos measuring 90 ,um in length could grow rapidly in phosphate-enriched White's medium (7). Plants were successfully regenerated from a callus that resulted from the growth of young wheat embryos (14-31 d old) on RM-64 media supplemented with 2,4-D (10). Plants from regenerable callus, obtained by growing immature embryos on MS' + 2,4-D, have even been reported to produce seeds (9). Again, immature embryos of Medicago sativa directly produced complete plants in hormone-free MS medium (5).Embryos that have completed organogenesis (mature embryos) but have failed to germinate in intact seeds under favorable germination conditions (presumably due to deterioration of inherent germination ability) have been reported to germinate successfully in culture media (3). Growth of mature, nongerminating (due to insufficient pre-germination imbibition) embryos of pea when cultured aseptically in hormone-free medium of Raghavan and Torry (8) was reported to respond to different concentrations of sucrose in the medium (4). Our work describes the effect of nutrient medium on rooting ability and the growth pattern of embryos isolated from appreciably deteriorated wheat seeds. MATERIALS AND METHODSWheat seeds (Triticum aestivum L. cv HD 2189) were obtained from Indian Agricultural Research Institute, New Delhi, India. Deteriorated wheat seeds showing low germination2 percentage (I1% G) were prepared by the method described earlier (2).Dehydrogenase activity was assayed by reducing TTC to form formazan. Hundreds of 99% G and 1% G wheat seeds were imbibed in water for 1 h and then incubated on moist cotton at 'Abbreviations: MS, Murashige and Skoog medium; G, germinating; HMS, half the concentration of all the components of MS medium; TTC, 2,4-triphenyltetrazolium chloride. 2Growth of embryos initiated by protrusion of radicle or plumule.25 ± 1°C for 1 h. The seeds were then cut longitudinally into two identical halves; each half was immersed in freshly prepared 0.2% TTC solution for 20 min at 25 ± 1°C. The half seeds were washed thoroughly in distilled water and were placed in moist cotton, embryo facing upward. The extent of colored region in each half was assessed visually. The stainability pattern of individual embryos was categorized into diagrammatic representations ( Fig. 1, A-F). The percentage of embryos stained under each category was scored in the two G stocks (viz. 99% and 1% G). The results are pres...

Protein repair l -isoaspartyl methyltransferase 1 (PIMT1) in rice improves seed longevity by preserving embryo vigor and viability

“…7c, d). The isolated embryos had higher germination percentages and this was also observed in wheat seed after artificial aging (Das and Sen-Mandi 1988;Petruzzelli and Taranto 1989). The greater germination percentage of isolated seed from the OE lines supported the conclusion that OsPIMT1 has a role in maintaining embryo vigor, and that OsPIMT1 is specifically involved in repairing isoAsp damage in the embryo proteome, which, in turn, enhances embryo and seed survival rates under artificial aging treatment.…”

10.1007/s11183-008-1003-6

“…The final germination percentage of seeds and fresh weight of seedlings produced decreased with increasing accelerated ageing, as was also found in wheat seeds by Guy and Black [26] and in Beta vulgaris seeds by Song et al [27]. As determined by tetrazolium staining, deterioration began from the root and moved through the embryo in both naturally and artificially aged Triticum aestivum seeds [28,29]; and embryonic axes of A. hypogaea were the most sensitive seed parts to deterioration [30]. 1a-1j).…”

Optimized qualitative and quantitative methods for barley viability testing using triphenyl tetrazolium chloride staining

“…Using TTC for assessing seed viability was originally developed by Lakon (1949). Since then, TTC has been used to evaluate the seed viability for various agricultural crops such as maize, wheat, barley, and rice (Bennett & Loomis, 1949;Das & Sen-Mandi, 1988;Harty, Paleg, & Aspinall, 1972). A quantitative TTC test by formazan extraction and quantifying formazan content using spectrophotometry was also reported before (Harty et al, 1972;Norton, 1985).…”