Seed germination performance of nine Arabica coffee (Coffea arabica L.) varieties under the laboratory condition after six months of storage period.

Coffee seeds are classified into intermediate seeds which require high moisture content during the storage and possess a short shelf life. Seed germination testing aims to determine the potential of a seed lot, evaluate seed quality during the storage and also to estimate the success of seedling in the nursery. This experiment aimed to determine the germination performance of several Arabica coffee varieties after being stored for six months at controlled temperature. Nine varieties of Arabica coffee, namely Abesinia-3, Andungsari-1, BLP, Gayo-2, Goiaba, Kartika-1, Kayumas, MP-3, and S-795 were used in this study. The seeds were harvested in the 2019 harvest season (September) and the germination was tested in April 2020. The germination test was carried out in laboratory by using petridish. The result showed that the tested Arabica coffee seeds still had a high germination percentage which was more than 85%. Only three varieties namely S-795, Abesinia-3, and Goiaba had low germination growth (<80%). Meanwhile, Kayumas, BLP, and Kartika-1 coffee varieties had the best germination growth with an average length of 34.19 mm; 39.79 mm and 39.41 mm, respectively. Kartika-1 variety needs 6–7 days to germinate; Kayumas, BLP, and Goiaba varieties took 7–8 days; S-795 and MP-3 took 10 days; as well as Andungsari-1, Abesinia-3, and Gayo-2 which took 10–12 days. Arabica coffee seeds that had a short germination time will had a high germination rate and otherwise. Each variety displayed a different germination performance. BLP, Kartika-1, Gayo-2 and MP-3 varieties had high potential germination, 86.67%; 89.17%; 86.67%, and 93.33%, respectively. Kayumas, BLP, and Kartika-1 varieties showed significantly longer germination, namely 34.19 mm; 39.79 mm and 39.41 mm, respectively. The fastest of average germination time was possessed by Kartika-1 variety (6.54 days) and the highest seed germination rate was also possessed by Kartika-1 variety (0.153 per day).

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.

Seed comparative genomics in three coffee species identify desiccation tolerance mechanisms in intermediate seeds

In contrast to desiccation-tolerant ‘orthodox’ seeds, so-called ‘intermediate’ seeds cannot survive complete drying and are short-lived. All species of the genus Coffea produce intermediate seeds, but they show a considerable variability in seed desiccation tolerance (DT), which may help to decipher the molecular basis of seed DT in plants. We performed a comparative transcriptome analysis of developing seeds in three coffee species with contrasting desiccation tolerance. Seeds of all species shared a major transcriptional switch during late maturation that governs a general slow-down of metabolism. However, numerous key stress-related genes, including those coding for the late embryogenesis abundant protein EM6 and the osmosensitive calcium channel ERD4, were up-regulated during DT acquisition in the two species with high seed DT, C. arabica and C. eugenioides. By contrast, we detected up-regulation of numerous genes involved in the metabolism, transport, and perception of auxin in C. canephora seeds with low DT. Moreover, species with high DT showed a stronger down-regulation of the mitochondrial machinery dedicated to the tricarboxylic acid cycle and oxidative phosphorylation. Accordingly, respiration measurements during seed dehydration demonstrated that intermediate seeds with the highest DT are better prepared to cease respiration and avoid oxidative stresses.

Regulatory redox state in tree seeds

Peroxiredoxins (Prx) are important regulators of the redox status of tree seeds during maturation and long-term storage. Thioredoxins (Trx) are redox transmitters and thereby regulate Prx activity. Current research is focused on the association of Trx with Prx in tree seeds differing in the tolerance to desiccation. The results will allow for better understanding the regulation of the redox status in orthodox, recalcitrant, and intermediate seeds. The findings will also elucidate the role of the redox status during the loss of viability of sensitive seeds during drying and long-term storage.

Orchid cryopreservation

Orchids are lush and highly valuable plants due to their diversity and the beauty of their flowers, which increases their commercialization. The family Orchidaceae comprises approximately 35,000 species, distributed among more than 1,000 distinct genera and 100,000 hybrids, totaling approximately 8% to 10% of all flowering plants. With the advance of agriculture and the constant destruction of their natural habitat, orchid species are collected in an indiscriminate manner by collectors and vendors, and this extractive activity threatens many species with extinction, drastically reducing their genetic variability in nature. Therefore, it is essential to seek alternatives that make the preservation of such species feasible using techniques with low maintenance costs that provide greater storage time and that enable good phytosanitary conditions for the plant material for commercial use. Cryopreservation involves the conservation of biological materials at ultra-low temperatures, generally in liquid nitrogen at -196 ºC or in its vapor phase at -150 ºC. This is the only technique currently available for the long-term preservation of the germplasm of plant species that are vegetatively propagated or that have unviable, recalcitrant or intermediate seeds. The objective of this bibliographic review is to report on the importance, methods and application of cryopreservation for orchids. According to the studies reviewed, this is an incipient, developing and relevant field that generates a lot of discussion and requires further research relative to the type of treatment to use for cryopreservation and the methodology to be applied according to the species. The types of methods that are used for cryopreservation and the large variation in the responses of orchids to the cryopreservation methods observed in this study emphasize the need for the development of more appropriate protocols for the preservation of orchids.

Colonization of a South Australian grassland by invading Mediterranean annual and perennial pasture species

Spatial variation in the composition of the soil seed bank was studied in a 5 ha area of pasture in South Australia dominated by naturalized annuals originating from the Mediterranean basin. The results were analysed with regression, cluster and principal component analysis. A total of 34 species was collected, including 17 grasses, seven legumes, eight broad-leaved species and two rushes. The total size of the seed bank was over 200 seeds dm-2, equivalent to about 450 kg ha-1 Although the site was nearly flat, elevation affected the distribution of all species, probably because of its effect on drainage in winter. Five legumes (Tbifilium clusii, T. ornithopioides, T. dubium, T. glomeratum and T. subterraneum) dominated the seed bank, but the dominant species changed with elevation above the zone of winter-waterlogging. Of the grasses Serrafalcus hordeaceus and Vulpia spp. were present at well drained sites, while Lolium perenne and Hordeum geniculatum were found at low sites, with Holcus lanatus intermediate. Seeds of legumes were more frequent at sites where soil nitrogen and phosphorus were low, and seeds of grasses where they were high. The results are compared with those obtained from perennial species in north Europe, and the implications for pasture deterioration and improvement in Australia are discussed. It is concluded that genetic diversity is likely to be important in the successful invasion of pasture by Mediterranean annuals. The presence of several naturalized legumes in niches incompletely occupied by subterranean clover suggests that germplasm is available to increase the legume component of many annual pastures