Germination of palm seeds under periods of rehydration

Palm seeds are indicative of being recalcitrant species. Seeds germination for many species, is slow and uneven, even in favorable conditions, often due to the resistance of the woody endocarp that makes them impermeable to water. Most species also have the characteristic of not tolerating the drying process at low moisture levels, thus losing their viability. In view of these considerations, the objective was to evaluate the effect of different periods of rehydration on the germinative process of seeds of royal palm, dwarf palm and jeriva. Seeds were homogenized and immersed in water containing 3 times their volume, with daily replacement. The experimental design used was completely randomized, with 5 treatments (0, 3, 6, 9, and 12 days of rehydration), with 4 replications of 25 seeds. The seeds were placed in transparent “gerbox” plastic boxes containing medium vermiculite as substrate and placed in BOD with a photoperiod of 16-hour of light and their respective optimum temperatures for each species. The number of germinated seeds was counted every 2 days until germination stabilized. The variables analyzed were germination percentage, germination speed index (GSI), average germination time (AGT) and distribution of germination over the days. Rehydration for 3 days increased the germination rate of royal palm seeds. For dwarf and jeriva species, rehydration did not influence the analyzed variables. The GSI and AGT were negatively influenced by the rehydration periods for royal palm. Rehydration prolonged the peak of germination of the studied species.

Antioxidant effect of cathodic water on seeds

ABSTRACT: Recalcitrant and intermediate seeds have limitations regarding conservation because of their sensitivity to desiccation and response to storage. Establishing a method for seed storage is difficult because these seeds deteriorate rapidly, which can intensify production of reactive oxygen species that cause lethal oxidative damage to plant tissues. Orthodox seeds, which have greater tolerance to desiccation and storage, are also subject to deterioration processes, in degrees that vary according to the species. Damage caused by harmful levels of free radicals can be mitigated by the action of endogenous or exogenous antioxidants. Recent studies have led to new technologies for protection coming from antioxidants, one of which is cathodic protection. This is a technique with promising results in recalcitrant species, as well as in other living organisms. This paper reviews results regarding the antioxidant activity of cathodic water produced from electrolysis of a calcium chloride and magnesium chloride solution.

Efficient Shoot Regeneration via Indirect Organaogenesis of a Highly Recalcitrant Species of Cissampelos pareira (L.)

An efficient protocol was standardized for successful regeneration of Cissampelos pareira (L.) through indirect organogenesis. Nodal explants were cultured on MS fortified with 0.5 ± 1.0 mg/l BAP, Kn either single or in combination with NAA 0.5 mg/l. The combinations induced profuse, compact, light green to greenish coloured calli. Some differences in the morphology of callus such as change in the colour and texture was also observed with increasing the concentration of BAP 0.5 ± 2.0 mg/l + NAA 0.5 mg/l. Maximum callus induction was observed on 1.0 mg/l BAP and 0.5 mg/l NAA showed greenish, friable and granular lush colour. The calli were subcultured on fresh MS that contained BAP and Kn single or in combination with NAA (BAP 0.5 ± 2.0 mg/l, Kn 0.5 ± 2.0 mg/l, NAA 0.5 mg/l). The maximum regeneration frequency of shoot organogenesis was recorded on BAP (2.0 mg/l) + NAA (0.5 mg/l). Healthy microshoots were separated and transferred to the rooting medium. Here, MS augmented with IBA 1.0 mg/l showed maximum rooting. Well rooted plantlets were transferred to the field and maximum survival frequency was recorded when BAP (1.0 mg/l) + NAA (0.5 mg/l) for callus induction, for shooting BAP (2.0 mg/l) + NAA (0.5 mg/l) and for rooting IBA (1.0 mg/l) was used. The regenerated whole plants were subjected for hardening where the maximum survival frequency was found to be 80%. This reproducible protocol can be used for regeneration and genetic transformation studies.