Ramiro Castillo

Effect of abscisic acid and jasmonic acid on partial desiccation of encapsulated somatic embryos of sugarcane

Embryogenic calli of sugarcane (Saccharum sp. hybrid, clone CP52-43), with somatic embryos in the late scutelar stage, were subjected to different treatments for increasing embryo tolerance to desiccation. The medium was supplemented with abscisic acid (ABA) (3.8 μM), jasmonic acid (JA) (4.7 μM) or a combination of them. A control treatment without growth regulators was also included. The embryos were encapsulated in alginate beads and dehydrated or not in sucrose (0.5 M). Thereafter, they were further dehydrated in chambers containing silicagel until the beads reached either 60% or 30% of water content (WC). Survival of encapsulated-dehydrated embryos was achieved only in the control and ABA treatment. ABA induced an increase in protein, polyamines, free proline levels and starch levels as a response to desiccation tolerance. JA treatment showed the lowest protein and polyamines levels and increased the starch content almost two-fold compared to the ABA treatment. The JA treatment induced high levels of 4-methylcatechol and the lowest levels of gallic acid. However, the ABA treatment increased gallic acid and p-coumaric acid content in the induction medium. Some differences were found in growth regulator free-medium in relation to the induction medium. JA is not effective in these desiccation processes. The mechanisms by which these two plant growth regulators act on the induction of tolerance to stress are presumably different.

Biochemical characterization of embryogenic and non-embryogenic calluses of sugarcane

SummaryWith the aim to determine a possible relationship between somatic embryogenesis and some metabolic contents in embryogenic and non-embryogenic calluses of sugarcane (Saccharum sp. var CP-5243), the present study was carried out. Embryogenic callus has more soluble proteins, free proline, proteolytic activity, soluble sugars, and invertase, and lower putreseine/(spermidine + spermine) than non-embryogenic tissue. Non-embryogenic callus has a higher peroxidase and gallic acid level, lower dry matter/fresh matter ratio, and more gross fat compared with embryogenic callus.

Field performance of artificial seed-derived sugarcane plants

This study shows the behaviour of sugarcane plants cv. CP-5243 derived from artificial seed compared with traditional and isolated bud methods. Artificial seed-acclimatised plants were planted in field conditions simultaneously with two-control treatments previously germinated: macropropagated plants derived from stems of three buds and axillary buds isolated from field-grown plants. Plants from artificial seed were taller and had a smaller diameter at 8 months, but these differences disappeared at 12 months. With respect to sugar analysis and yield, no differences in all parameters evaluated were found between artificial seed-derived plants and plants derived from the two other methods.

Storage proteins in sugarcane : An interesting exception in monocots

Storage proteins were extracted from sugarcane seeds, globular embryos (formed on embryogenic calluses and collected in early developmental stages) and embryogenic cells. In all cases, the major percentage of storage proteins were albumins and globulins and the lower percentage were prolamins and glutelins. Sugarcane is an interesting exception in monocots which usually have high levels of prolamins and glutelins.