Seed Storage Behaviour Research Articles

In vitro propagation and acclimatization of genipapo accessions

ABSTRACT Genipapo is a species with an intermediate seed storage behavior, and its germination is slow and asynchronous; therefore the tissue culture is an alternative strategy for the propagation in large-scale. This study aimed to evaluate three genipapo accessions at different micropropagation stages (adventitious shoot induction, in vitro rooting and acclimatization). Genipapo nodal segments from the Sabinópolis (AS), Cruz das Almas (CZA) and Núcleo Bandeirante (NB) accessions were used and inoculated in culture media with 0 and 1.0 mg L-1 6-benzylaminopurine (BAP). Different indole-3-butyric acid (IBA) concentrations were tested for in vitro rooting. Subsequently, the effect of two substrates on the seedling development of three genipapo accessions was assessed. The molecular characterization of accessions was performed using 15 inter-simple sequence repeat (ISSR) primers, and genotype clustering was performed based on genetic dissimilarity using the Unweighted Pair-Group Method with Arithmetic Mean (UPGMA). Culture media supplementation with 1.0 mg L-1 BAP favors the development of adventitious shoots and promotes a higher callogenesis percentage, leaf number and feasibility at 90 days of in vitro culture. The immersion of the basal portion of shoots for 20 seconds in all IBA solutions induces the rhizogenesis in the genipapo accessions at 90 days of in vitro culture. The substrates consisting of washed sand + dried coconut shell powder, at a 1:1 ratio by volume, and Topstrato HT(r) may be recommended for genipapo acclimatization. The NB accession is genetically different from the CZA and AS populations and shows superiority for most of the variables analyzed.

Storage behavior and cryopreservation studies in Indian rough lemon (Citrus jambhiri): a promising rootstock for long-term conservation

The study of the seed storage behavior and cryopreservation of embryonic axes was attempted in Citrus jambhiri genotypes using air desiccation-freezing, vitrification, and encapsulation-dehydration methods. Seeds of this species revealed nonorthodox seed storage behavior with moderate seed longevity and sensitivity to desiccation and freezing. Successful cryopreservation was achieved with all three methods using embryonic axes; however, the recovery growth percentage significantly differed among these methods. Cryopreservation was efficient for the embryonic axes desiccated to 13%-15% moisture content. Freezing of embryonic axes at this moisture content in liquid nitrogen showed a good recovery rate of 40%-50%. In the vitrification method, embryonic axes subjected to PVS2 treatment for 40 min had the highest recovery rate of 25% after cryopreservation. In the encapsulation-dehydration method, encapsulated axes precultured on 0.5 M sucrose medium followed by 6 h of desiccation had the highest recovery growth of 30%-60% after cryopreservation. Out of the three methods employed, the encapsulation-dehydration method gave the best recovery values for embryonic axes. High regeneration values of embryos in comparison to embryonic axes prompted us to undertake large-scale cryobanking of C. jambhiri using embryos (seeds without seed coats) and more than 100 accessions of C. jambhiri have been cryostored in the national cryobank. This would further serve the purpose of conserving nucellar embryos with zygotic embryos.

Correlation and path analysis studies in seed quality and storability characteristics of Pongamia genotypes

Pongamia is an important source for biodiesel production. As it is propagated only though seed, seed storage behaviour plays a major role in deciding the success of any afforestation programme. Keeping this in view, an experiment was conducted during 2014 and 2015 to find out correlations among twenty four pongamia genotypes for sixteen seed storability traits. Fifteen traits have a positive significant correlation with seed storability at both genotypic and phenotypic levels. The genotypic correlation coefficient values were recorded to be higher than corresponding phenotypic values. Seed storability trait expressed positive significant correlation with all fourteen traits, except with the number of simple leaves. Initial seed quality traits like seed germination, speed of germination and number of trifoliate leaves and storability traits like speed of germination, seedling length, seedling dry weight, seedling vigour index-I and number of trifoliate leaves after seed storage showed positive direct effect on pongamia seed storability both at genotypic and phenotypic levels. Seedling vigour index- II and seedling length before storage showed direct negative effect on pongamia seed storability at both genotypic and phenotypic association levels. Hence, it is revealed that the selection and breeding on the basis of traits that show positive direct effect may aid in the tree improvement programmes of the species for high seed storability in pongamia .

Seed Storage Behavior and Seed Germination of Nine Species of Lauraceae from Yunnan, China

Seed Storage Behavior and Seed Germination of Nine Species of Lauraceae from Yunnan, China

Investigations on ex situ conservation of selected Australian palms

Of the approximately 2500 species of Arecaceae, only a very small number has been studied extensively due to their global economic significance. This includes date palm, oil palm and coconut. Other palm species are generally under-studied since they are not well known outside of their natural distribution despite the likelihood of contributing considerably to the local economy. While the western culture generally regards palms as ornamentals, palm and palm products are an integral part of life in the tropics and sub-tropics. Over-exploitation and other land-use pressures in these regions have resulted in the disappearance of many species from wild stands; while climate change coupled with stresses like weeds is forecasted to exacerbate the rate of loss. Consequently, Arecaceae has been increasingly recognised as a susceptible family with 65% of the species recorded by International Union for Conservation of Nature (IUCN) under the LSQUOthreatenedRSQUO category, hence the need for conservation and propagation. A major hurdle for in situ conservation of palms is germination, which can take up to years, while the absence of lateral buds impedes conventional vegetative propagation. This study focuses on the development of ex situ conservation methods for selected Australian palms in the genera Livistona and Archontophoenix. This includes investigations on seed storage behaviour and in vitro germination of zygotic embryos as a precursor to developing cryopreservation techniques. The results of this investigation indicate that A. cunninghamiana seeds are desiccation-sensitive whilst L. decora and L. nitida seeds are desiccation-tolerant. This suggests that seeds of these Livistona spp. may be stored using standard seed storage methods and will allow for collection and long-term seed storage of these species. This is currently being tested. For A. cunninghamiana, which is desiccation sensitive, further investigations for viability at a range of moisture contents and temperatures, including liquid nitrogen storage to try to develop a reliable seed storage protocol are currently being done. As an alternative to seed storage, in vitro germination of zygotic embryos has been investigated as a precursor to a possible cryopreservation of zygotic embryos. The results indicate that germination of zygotic embryos is both rapid and effective and this method will now be used in the development of A. cunninghamiana embryos.

English

Identification of the seed storage behaviour of a target species is essential prior to seed storage so that suitable storage strategies are taken. In the present experiments, germination characteristics, desiccation, and low temperature tolerance of seeds of Sophora tonkinensis was studied; a traditional Chinese medicine on the edge of extinction, were investigated for the first time in attempt to interpret their storage behaviour. The results indicate that the temperature optimum for seed germination ranged from 25 to 30°C, the seed germination was non-photoblastic, the seed viability declined with the decrease of moisture content by a silica gel desiccation, and a low temperature storage at -20°C for 3 months had no significant effects on the seeds desiccated to 5.4 ± 0.1% moisture content. These results suggest an intermediate seed storage behaviour. For germplasm long-term conservation purpose, a cryopreservation investigation was proposed.   Key words: Seed, desiccation tolerance, low temperature tolerance, germination, Sophora tonkinensis.

Effects of temperature, light, desiccation and cold storage on germination of Sophora tonkinensis (Leguminosae) seeds

Identification of the seed storage behaviour of a target species is essential prior to seed storage so that suitable storage strategies are taken. In the present experiments, germination characteristics, desiccation, and low temperature tolerance of seeds of Sophora tonkinensis was studied; a traditional Chinese medicine on the edge of extinction, were investigated for the first time in attempt to interpret their storage behaviour. The results indicate that the temperature optimum for seed germination ranged from 25 to 30°C, the seed germination was non-photoblastic, the seed viability declined with the decrease of moisture content by a silica gel desiccation, and a low temperature storage at -20°C for 3 months had no significant effects on the seeds desiccated to 5.4 ± 0.1% moisture content. These results suggest an intermediate seed storage behaviour. For germplasm long-term conservation purpose, a cryopreservation investigation was proposed. Key words: Seed, desiccation tolerance, low temperature tolerance, germination, Sophora tonkinensis .

Germinación de semillas de cuatro especies arbóreas del bosque seco tropical del Valle del Cauca, Colombia

The ecological restoration strategies for highly threatened ecosystems such as the tropical dry forest, depend on the knowledge of limiting factors of biological processes for the different species. Some of these include aspects such as germination and seed longevity of typical species present in those forests. In this study, we evaluated the effect of light and temperature on seed germination of two Fabaceae (Samanea saman and Jacaranda caucana) and two Bignoniaceae (Pithecellobium dulce and Tabebuia rosea) species having potential use in restoration, and we analyzed the seed storage behavior of these species for a three months period. To study the light effect, four levels of light quality on seeds were used (photoperiod of 12 hours of white light, darkness and light enriched in red and far-red, both for an hour each day), and we combined them with three levels of alternated temperatures (20/25, 20/30 and 25/30*C-16/8h). For the storage behavior, two levels of seed moisture content particular for each species were used (low: 3.5-6.1% and high: 8.3-13.8%), with three storage temperatures (20, 5 and -20 degrees C) and two storage times (one and three months). The criterion for germination was radicle emergence which was measured in four replicates per treatment, and was expressed as percentage of germination (PG). There were significant differences in germination of Samanea saman and Jacaranda caucana among light and temperature treatments, with the lowest value in darkness treatments, whereas germination of Pithecellobium dulce and Tabebuia rosea did not differ between treatments (PG>90%). The most suitable temperature regime to promote germination in all species was 25/30 degrees C. These four species showed an orthodox seed storage behavior. We concluded that seeds of R dulce, J. caucana and T. rosea did not have an apparent influence of all light conditions tested in their germination response, which might confer advantages in colonization and establishment processes, while S. saman did not germinate well in darkness. We suggest the use of seeds of P dulce, J. caucana and T rosea in ecological restoration processes, due to their tolerance and germination under a wide range of temperature and light conditions. Futhermore, seeds of S. saman might be used in open areas such as forest gaps.

Seed viability and oil content in seeds ofPongamia pinnataof five sources stored at different moisture and temperature regimes

The present research was conducted with the objective to study the variation in seed oil content among five seed sources across diverse agro-climatic conditions and storage behaviour of seeds up to two years. Seeds collected in May 2010 were stored up to May 2012 at three moisture levels (6%, 9% and normal), two temperature regimes (room temp. and-5°C) and three types of containers (cloth bags, polythene bags and air tight containers). The parameters of oil content (%), germination (%), seedling length (cm), seedling dry weight (mg) and seedling vigour (index-I & II) were measured. Seeds collected from the test trees of different agro-climatic zones were bulked zone-wise (seeds collected from all the 10 test trees from one agro-climatic zone were bulked). The seeds from each agro-climatic zone were divided into three equal parts. The maximum oil content was in RJ-7 agroclimatic zone and minimum in PB-3 agro-climatic zone. The oil content decreased with passage of time. Decline in the seed oil content was not significant up to a period of 12 months but by 24th month of storage the oil content declined significantly up to 6%. There was no germination after 12 months in the seeds stored at room temperature with normal and 9% moisture content irrespective of the type of containers used for storage. Seedling vigour declined significantly with increasing period of storage. Seeds stored in polythene bags and air tight containers had higher seedling length than cloth bag storage. Seeds with 6% moisture level stored at-5°C retained viability up to 16 months in air tight containers. The oil content was maximum (34.75%) in RJ-7 agro-climatic zone.

Classification of seed storage behaviour of 67 Amazonian tree species

Information was collated on the seed storage behaviour of 67 tree species native to the Amazon rainforest of Brazil; 38 appeared to show orthodox, 23 recalcitrant and six intermediate seed storage behaviour. A double-criteria key based on thousand-seed weight and seed moisture content at shedding to estimate likely seed storage behaviour, developed previously, showed good agreement with the above classifications. The key can aid seed storage behaviour identification considerably.

Desiccation tolerance and cryopreservation of seeds of black poplar (Populus nigra L.), a disappearing tree species in Europe

Black poplar (Populus nigra L.) is a widely distributed species that plays a crucial role in riparian forest ecosystems. Due to a reduction in its natural habitats and hybridization with introduced poplar species clones, its genetic pool is decreasing and efforts are required to preserve this species. Seeds of black poplar are short-lived and quickly lose viability during conventional storage in gene banks. Therefore, in order to preserve ex situ the genetic diversity of this species, the feasibility of seed cryopreservation in liquid nitrogen (at −196 °C, LN) for periods of 24 h and 2 years was investigated. Seeds were harvested from three individual trees (two provenances) and desiccated to different levels of water content (WC) in the range of 0.02–0.35 g g−1 (g H2O/g dry mass, g g−1) prior to immersion in LN. Seed germination was assessed after each treatment. P. nigra seeds tolerated desiccation to WC 0.07 g g−1 but after severe desiccation to WC <0.05 g g−1 exhibited a significant reduction in germination. Results indicated that all black poplar seeds, regardless of origin, year of harvesting and seed quality, could be cryopreserved for 24 h when their WC was in the range of 0.11–0.17 g g−1. Physiology of P. nigra seeds showed in this paper is consistent with attributes of intermediate seed storage behavior. This study provides a foundation for using cryopreservation for the ex situ conservation of P. nigra seeds.

In vitro propagation and shoot encapsulation as tools for ex situ conservation of the aquatic plant Ludwigia palustris (L.) Ell.

Ludwigia palustris (L.) Ell. is an aquatic perennial herb present in several regions of Italy, which is one of its native countries. In this research, micropropagation and encapsulation protocols were established from axillary buds of L. palustris. Shoots proliferated on half-strength Murashige and Skoog medium without growth regulators. Different culture vessels were tested. Shoots in GROWTEK bioreactor showed the highest fresh and dry weight and total length while the plantlets grown in the RITA bioreactor showed the highest shoot number per explant. Encapsulation of L. palustris microcuttings with sodium alginate formed small and whitish beads which were stored for 14 or 28 days at 7° or 25°C. Storage for 14 days at both temperatures gave the best results but prolonged storage at 25°C decreased the shoot viability to 73%. After 4 weeks of recovery, all the plantlets showed the typical features of the species. Even though the latest Italian IUCN Red List does not mention L. palustris, conservation measures are proposed at local level because this species locally remains vulnerable mainly due to the loss of adequate habitats.Our protocol could be one of the methods for ex situ conservation of L. palustris particularly because its seed storage behavior is uncertain.

Seed storage behaviour of 101 woody species from the tropical rainforest of southern China: a test of the seed-coat ratio–seed mass (SCR–SM) model for determination of desiccation sensitivity

The Xishuangbanna tropical rainforest in Yunnan Province is the greatest biodiversity hotspot in China. However, the biodiversity of this region is under threat, making seed conservation through seed and/or germplasm banking particularly urgent and crucial. Seed desiccation sensitivity limits the possibility of seed banking of 47% of tropical rainforest species. Thus, knowing if a species has desiccation-sensitive seeds is an important first step in seed banking; however, often resources are limited, making it difficult to determine storage behaviour for all the species in a region. Prediction of seed sensitivity using the SCR–SM model based on seed-coat ratio (SCR) and seed dry mass (SM) might be an alternative for determining desiccation sensitivity of seeds of each species. Here, seed-desiccation sensitivity of 101 woody species from the Xishuangbanna tropical forest were analysed using this model, and physiological determinations were made for a total of 25 species. Seed storage behaviour for 59 species was used for model validation, and storage behaviour of 88% of these species was successfully predicted. Seed storage behaviour of 83% of the 59 species was successfully predicted using the 1000-seed weigth–moisture content (TSW–MC) criteria, which include seeds with 1000-seed weight &gt;500 g and seed moisture content at shedding of 30 –70%. The two predictive methods were subsequently used to predict seed desiccation sensitivity for another 42 species from Xishuangbanna whose storage behaviour was uncertain. Our results indicated that ~50% of the species in Xishuangbanna are likely to have desiccation-sensitive seeds.

Advances in seed conservation of wild plant species: a review of recent research.

Seed banking is now widely used for the ex situ conservation of wild plant species. Many seed banks that conserve wild species broadly follow international genebank guidelines for seed collection, processing, storage, and management. However, over the last 10-20 years, problems and knowledge gaps have been identified, which have led to more focused seed conservation research on diverse species. For example, there is now greater ecogeographic understanding of seed storage behaviour and of the relative longevity of orthodox seeds, and we are therefore able to predict which species should be conserved using cryostorage techniques; seed development studies have identified when seeds should be harvested for maximal tolerance of desiccation and longevity in storage, as well as highlighting how seed development can vary between species; and there is now a wealth of literature on the dormancy-breaking and germination requirements of wild species which, as well as enabling better management of accessions, will also mean that their use in restoration, species reintroduction, or for evaluation for other applications is possible. Future research may be focused, for example, on nursery and plant production systems for wild plant species that maximize genetic diversity, so that introduced seeds and plant materials have the resilience to cope with future environmental stresses.

Morphology, ecophysiology and germination of seeds of the Neotropical tree &lt;i&gt;Alibertia patinoi&lt;/i&gt; (Rubiaceae)

Alibertia patinoi (Rubiaceae) is of economic and cultural importance for communities in the Colombian Pacific and Amazon regions, where it is cultivated and mature fruits are highly appreciated and consumed. Since there is a lack of knowledge of the seed physiology of this species, we describe here the germination behavior and morphometry of seeds of Alibertia patinoi, and relate them to its habitat. Fruits were collected from a mixed food crop and a commercial plantation in Guaimía village, Buenaventura, Colombia, a tropical rain forest area. We measured length, width, thickness, mass (n = 1 400), and moisture content of seeds (n = 252). Primary dormancy tests were conducted (n = 200), followed by imbibition (n=252) and germination dynamics, under different conditions of light and temperature specific to understory and forest clearings (n = 300 seeds). Finally, seed storage behavior was established (n = 100 seeds). We observed that size and mass of seeds had a narrow range of values that did not differ within or among fruits and that the species did not exhibit primary dormancy. The seeds are recalcitrant, and recently harvested seeds exhibited higher seed moisture content (ca. 44%) and continuous metabolism. The seed germination percentage was observed to be higher under the specific dense canopy forest light and temperature conditions; furthermore, neither enriched far-red light nor darkness conditions inhibited germination. We concluded that rapid germination could be the establishment strategy of this species. Also, the physiological traits (i.e., rapid germination rate, low germination requirements, absence of primary dormancy, and recalcitrant behavior) and seed size and mass, suggest that A. patinoi is adapted to conditions of mature tropical rain forests.

Germination capacity and seed storage behaviour of threatened metallophytes from the Katanga copper belt (D.R.Congo): implications for ex situ conservation

Background and aims – Plant species adapted to metalliferous soil are of high conservation value, and actions for preserving these species (some of them are endemics) are urgent given the threat of mining activities. In the framework of an integrated conservation programme of cuprophytes (plants that tolerate a soil with a high level of copper) in Katanga (D. R. Congo), this study aims at: (1) providing new data on species whose germination has never been studied so far; (2) gaining new insight into the storage behaviour of these species; (3) discussing implications for ex situ conservation of these highly threatened species. Methods – Germination tests were conducted on fresh seeds of nineteen species. These tests were repeated after 6, 12 and 24 months of storage in dry-cold conditions. Key results – Most species kept or increased their germination capacity after 2 years storage in dry-cold conditions. Nine species showed a slight decrease in their viability (from 100% to &gt; 80%) after 2 years storage in dry-cold conditions. The present study gives evidence that at least six of the 19 studied species are desiccation-tolerant (orthodox). Among these, two are strict endemics, Haumaniastrum robertii and Faroa malaissei, and two are broad endemics, Diplolophium marthozianum and Gladiolus robiliartianus . This means that ex situ seed banking of these species could form a useful part of a more comprehensive conservation strategy. Only two species have been identified as desiccation-sensitive (recalcitrant), i.e.inappropriate for conservation in standard seed bank conditions. An orthodox behaviour has not been ruled out for the other species tested, but their response was less clear and needs further investigation.

Seed dormancy and storage behaviour in tropical Fabaceae: a study of 100 species from Sri Lanka

AbstractSeeds of legumes are generally considered to have physical dormancy and to be orthodox, but most seed biologists are unaware of the various kinds and combinations of dormancy and storage behaviour in seeds of this family. The aim of our study was to document the dormancy and storage behaviour of seeds of 100 native and introduced tropical Fabaceae species in Sri Lanka and classify them into germination/storage behaviour categories. Moisture content (MC) was &lt; 16% for fresh seeds of 94 species and &gt;29% for those of six. Seeds of these six species had low tolerance for desiccation and for low temperatures. Thus, seeds of six species are non-orthodox and 94 species orthodox. Nine of the 100 species were non-dormant, and 2, 3 and 86 had physiological, physiological epicotyl and physical dormancy, respectively. Six germination/storage behaviour categories were identified among the 100 species. However, as in extratropical regions of the world, orthodox storage behaviour and physical dormancy are characteristic of seeds of the majority of species of Fabaceae in tropical Sri Lanka.

Current status of coffee genetic resources and implications for conservation.

Coffee genetic resources are being lost at a rapid pace, leading to loss of genetic diversity. Some of the threats contributing to the erosion of coffee genetic diversity include human population pressures, which lead to conversion of land to agriculture, deforestation and land degradation; low coffee prices leading to abandoning of coffee trees in forests and gardens and shifting cultivation to other more remunerative crops; and global climate change. Conservation of coffee germplasm as seeds is not a viable option because of the recalcitrant/intermediate storage behaviour of seeds. Hence, development of a comprehensive conservation strategy for coffee should take into account complementary methods of in situ and ex situ conservations. The development of molecular techniques has expanded the possibilities and tools for genetic analysis for efficient conservation and use of coffee genetic resources. Before it is too late, a thorough evaluation of existing germplasm should be performed based on which a comprehensive conservation strategy can be developed.

The physiology of extremely desiccated Brassica juncea (L) seeds

Seeds of four raya cvs., viz. RL 1359, RLM 198, RLM 619 and RLM 514 were desiccated for 2, 7, 15 and 45 days wchich led to different levels of seed moisture. Data on germination capacity speed of germination, seedling dry weight, electrical conductance, dehydrogenase activity and seed storage behaviour for up to two years after desiccation were recorded. Based on this data, cvs. RL 1359 and RLM 514 were found to be tolerant to desiccation 10 as low as 0.73 and 1.16 per cent seed moisture levels, respectively. Seeds of RLM 198 tolerated desiccation up to 2.28 per cent seed moisture. However, RLM 619 seeds showed desiccation injuries in seedling dry weight, electrical conductance and speed of germination at moisture levels below 5.67 per cent.

Role of Relative Humidity in Processing and Storage of Seeds and Assessment of Variability in Storage Behaviour in Brassica spp. and Eruca sativa

The role of relative humidity (RH) while processing and storing seeds of Brassica spp. and Eruca sativa was investigated by creating different levels of relative humidity, namely, 75%, 50%, 32%, and 11% using different saturated salt solutions and 1% RH using concentrated sulphuric acid. The variability in seed storage behaviour of different species of Brassica was also evaluated. The samples were stored at 40 ± 2°C in sealed containers and various physiological parameters were assessed at different intervals up to three months. The seed viability and seedling vigour parameters were considerably reduced in all accessions at high relative humidity irrespective of the species. Storage at intermediate relative humidities caused minimal decline in viability. All the accessions performed better at relative humidity level of 32% maintaining seed moisture content of 3%. On analyzing the variability in storage behaviour, B. rapa and B. juncea were better performers than B. napus and Eruca sativa.