Co-adaptation of seed dormancy and flowering time in the arable weed Capsella bursa-pastoris (shepherd's purse)

Background and Aims

The duration of the plant life cycle is an important attribute that determines fitness and coexistence of weeds in arable fields. It depends on the timing of two key life-history traits: time from seed dispersal to germination and time from germination to flowering. These traits are components of the time to reproduction. Dormancy results in reduced and delayed germination, thus increasing time to reproduction. Genotypes in the arable seedbank predominantly have short time to flowering. Synergy between reduced seed dormancy and reduced flowering time would create stronger contrasts between genotypes, offering greater adaptation in-field. Therefore, we studied differences in seed dormancy between in-field flowering time genotypes of shepherd''s purse.

Methods

Genotypes with early, intermediate or late flowering time were grown in a glasshouse to provide seed stock for germination tests. Secondary dormancy was assessed by comparing germination before and after dark-incubation. Dormancy was characterized separately for seed myxospermy heteromorphs, observed in each genotype. Seed carbon and nitrogen content and seed mass were determined as indicators of seed filling and resource partitioning associated with dormancy.

Key Results

Although no differences were observed in primary dormancy, secondary dormancy was weaker among the seeds of early-flowering genotypes. On average, myxospermous seeds showed stronger secondary dormancy than non-myxospermous seeds in all genotypes. Seed filling was similar between the genotypes, but nitrogen partitioning was higher in early-flowering genotypes and in non-myxospermous seeds.

Conclusions

In shepherd''s purse, early flowering and reduced seed dormancy coincide and appear to be linked. The seed heteromorphism contributes to variation in dormancy. Three functional groups of seed dormancy were identified, varying in dormancy depth and nitrate response. One of these groups (FG-III) was distinct for early-flowering genotypes. The weaker secondary dormancy of early-flowering genotypes confers a selective advantage in arable fields.     

Pleistocene dynamics of the Eurasian steppe as a driving force of evolution: Phylogenetic history of the genus Capsella (Brassicaceae)

Capsella is a model plant genus of the Brassicaceae closely related to Arabidopsis. To disentangle its biogeographical history and intrageneric phylogenetic relationships, 282 individuals of all five currently recognized Capsella species were genotyped using a restriction digest‐based next‐generation sequencing method. Our analysis retrieved two main lineages within Capsella that split c. one million years ago, with western C. grandiflora and C. rubella forming a sister lineage to the eastern lineage consisting of C. orientalis. The split was attributed to continuous latitudinal displacements of the Eurasian steppe belt to the south during Early Pleistocene glacial cycles. During the interglacial cycles of the Late Pleistocene, hybridization of the two lineages took place in the southwestern East European Plain, leading to the allotetraploid C. bursa‐pastoris. Extant genetic variation within C. orientalis postdated any extensive glacial events. Ecological niche modeling showed that suitable habitat for C. orientalis existed during the Last Glacial Maximum around the north coast of the Black Sea and in southern Kazakhstan. Such a scenario is also supported by population genomic data that uncovered the highest genetic diversity in the south Kazakhstan cluster, suggesting that C. orientalis originated in continental Asia and migrated north‐ and possibly eastwards after the last ice age. Post‐glacial hybridization events between C. bursa‐pastoris and C. grandiflora/rubella in the southwestern East European Plain and the Mediterranean gave rise to C. thracica. Introgression of C. grandiflora/rubella into C. bursa‐pastoris resulted in a new Mediterranean cluster within the already existing Eurasian C. bursa‐pastoris cluster. This study shows that the continuous displacement and disruption of the Eurasian steppe belt during the Pleistocene was the driving force in the evolution of Capsella.     

Spatial distribution of mRNA during pre-fertilization ovule development in Capsella bursa-pastoris

Summary In situ hybridization of sections of the ovary and ovule of Capsella bursa-pastoris with ³H-polyuridylic acid [³H-poly(U)] showed the presence of polyadenylic acid-containing RNA [poly(A) + RNA] in the cells of the placenta and nucellus. During megasporogenesis there was a decrease in ³H-poly(U) binding activity of the nucellar cells concomitant with the appearance of poly(A) + RNA in the integuments. As the typical eight-nucleate embryo sac was formed, ³H-poly(U) binding was not apparent around the quartet of nuclei at the chalazal end, while it persisted at the micropylar end. Both the egg and synergids as well as the chalazal proliferating tissue showed high concentrations of poly(A) + RNA in their cytoplasm. The results suggest a role for transient localizations of poly(A) + RNA during female sporogenesis and gametogenesis in C. bursa-pastoris.     

Germination behaviour in populations ofCapsella bursa-pastoris (Cruciferae)

Germination behaviour of variousCapsella bursa-pastoris populations collected from Scandinavia, Middle Europe and the Alps, was tested in unheated, non-illuminated greenhouses (46 populations) and in growth chambers using 5–7 alternating temperature regimes (16 populations). For all populations, the influence of temperature on germination rate is straightforward: the higher the temperature, the greater the germination. Germination capacity, however, may depend on the geographical region. There is also a strong seed age effect on both, rate and capacity of germination. Once dormancy was broken, seeds from all populations were able to germinate over the entire range of temperatures. Some populations revealed a more or less pronounced temperature optimum for germination capacity, others germinated equally well over the entire temperature range. This indicates genetic heterogeneity between populations. However, no correlation between germinability and any environmental pattern was detected. The data indicate thatCapsella bursa-pastoris has adopted a germination strategy which includes a broad temperature tolerance. Germination of wildCapsella plants seems to be regulated by the factors contributing to the inception and breaking of dormancy which depend on pre- and postharvest conditions. Adaptation in germination behaviour inCapsella bursa-pastoris is different from that in other life history traits (flowering behaviour, growth form parameters).     

Production and genetic analysis of partial hybrids in intertribal crosses between Brassica species (B. rapa, B. napus) and Capsella bursa-pastoris

Capsella bursa-pastoris (L.) Medic (2n = 4x = 32) is a natural double-low (erucic acid < 1%, glucosinolates < 30 micromol/g) germplasm and shows high degree of resistance to Sclerotinia sclerotiorum. Hybridizations were carried out between two Brassica species viz. B. rapa (2n = 20) and B. napus (2n = 38) as female and C. bursa-pastoris as male parent to introduce these desirable traits into cultivated Brassica species. Majority of F(1) plants resembled female parents in morphology and only a few expressed some characters of male parent, including the white petals. Based on cytological observation of somatic cells, the F(1) plants were classified into five types: two types from the cross with B. rapa, type I had 2n = 27-29; type II had 2n = 20; three types from the crosses with B. napus, type III was haploids with 2n = 19; type IV had 2n = 29; type V had 2n = 38. One to two chromosomes of C. bursa-pastoris were detected in pollen mother cells (PMCs) of type I plant by genomic in situ hybridization (GISH), together with chromosomal segments in ovary cells and PMCs of some F1 plants. Amplified fragment length polymorphism (AFLP) bands specific for the male parent, novel for two parents and absent bands in Brassica parents were generated in majority of F1 plants, even in Brassica-types and haploids, indicating the introgressions at various levels from C. bursa-pastoris and genomic alterations following hybridization. Some Brassica-type progeny plants had reduced contents of erucic acid and glucosinolates associated with improved resistance to S. sclerotiorum. The cytological and molecular mechanisms behind these results are discussed.     

Somatic embryogenesis from cell suspension and protoplast cultures ofCapsella bursa-pastoris (L.) Medic

Summary Rapidly growing cell suspension cultures of shepherd’s purse (Capsella bursa-pastoris L. Medic.) were established from leaf-derived calli. These suspensions remained unorganized in the presence of 2,4-D, but underwent extensive root organogenesis in a growth regulator-free liquid medium. Attempts to induce direct embryogenesis in liquid cultures were unsuccessful, but numerous embryos were obtained from cells plated onto growth-regulator-free solid medium. These embryos were frequently abnormal, and secondary embryogenesis was problematic for plant recovery but fertile plants were recovered. Viable protoplasts could readily be isolated from these cell suspensions. After 1 wk of culture, protoplast viability was 62%, and 7% of the cells had divided. Embryogenesis was observed from protoplast-derived microcolonies, plated on growth-regulator-free medium. Although these somatic embryos were difficult to root, plants were recovered. New cell suspensions were more recently established, which were only 4 to 6 mo. old when plant regeneration was attempted. Numerous shoots were obtained when these cells were plated onto growth-regulator-free solid media. However, these shoots differed from the embryos previously obtained in that they readily rooted and rapidly developed into plantlets. This system may allow the use of shepherd’s purse as a gene source for introgression of agronomically interesting traits intoBrassica crop species through protoplast manipulation and somatic hybridization.     

Independent FLC Mutations as Causes of Flowering-Time Variation in Arabidopsis thaliana and Capsella rubella

Capsella rubella is an inbreeding annual forb closely related to Arabidopsis thaliana, a model species widely used for studying natural variation in adaptive traits such as flowering time. Although mutations in dozens of genes can affect flowering of A. thaliana in the laboratory, only a handful of such genes vary in natural populations. Chief among these are FRIGIDA (FRI) and FLOWERING LOCUS C (FLC). Common and rare FRI mutations along with rare FLC mutations explain a large fraction of flowering-time variation in A. thaliana. Here we document flowering time under different conditions in 20 C. rubella accessions from across the species’ range. Similar to A. thaliana, vernalization, long photoperiods and elevated ambient temperature generally promote flowering. In this collection of C. rubella accessions, we did not find any obvious loss-of-function FRI alleles. Using mapping-by-sequencing with two strains that have contrasting flowering behaviors, we identified a splice-site mutation in FLC as the likely cause of early flowering in accession 1408. However, other similarly early C. rubella accessions did not share this mutation. We conclude that the genetic basis of flowering-time variation in C. rubella is complex, despite this very young species having undergone an extreme genetic bottleneck when it split from C. grandiflora a few tens of thousands of years ago.     

Capsella as a model system to study the evolutionary relevance of floral homeotic mutants

Several lines of evidence suggest that homeotic changes played a considerable role during the evolution of flowers. This, however, is difficult to reconcile with the predominant evolutionary theory which rejects any drastic, saltational change of the phenotype as reasonable mode of evolution due to its assumed negative impact on the fitness of the affected organism. A better understanding of the evolutionary potential of homeotic transitions requires a study of the performance of respective mutant varieties in the wild. Here we introduce ``Stamenoid petals' (Spe), a variety of Capsella bursa-pastoris (shepherd's purse), as a suitable model to study the evolutionary potential of floral homeotic mutants. In the flowers of the Spe variety all petals are transformed into stamens, while all other floral organs are unaffected. In contrast to most other homeotic mutants the Spe variety occurs on several locations in relatively large and stable populations in the wild. Due to its close relationship to the model plant Arabidopsis thaliana, the Spe variety of C. bursa-pastoris can be rigorously studied, from the molecular genetic basis of the phenotype to its consequences on the fitness in wild habitats. Investigations on Spe may thus help to clarify whether homeotic transformations have the potential to contribute to macroevolution.     

Drosophila Trap1 protects against mitochondrial dysfunction in a PINK1/parkin model of Parkinson's disease

Mitochondrial dysfunction caused by protein aggregation has been shown to have an important role in neurological diseases, such as Parkinson''s disease (PD). Mitochondria have evolved at least two levels of defence mechanisms that ensure their integrity and the viability of their host cell. First, molecular quality control, through the upregulation of mitochondrial chaperones and proteases, guarantees the clearance of damaged proteins. Second, organellar quality control ensures the clearance of defective mitochondria through their selective autophagy. Studies in Drosophila have highlighted mitochondrial dysfunction linked with the loss of the PTEN-induced putative kinase 1 (PINK1) as a mechanism of PD pathogenesis. The mitochondrial chaperone TNF receptor-associated protein 1 (TRAP1) was recently reported to be a cellular substrate for the PINK1 kinase. Here, we characterise Drosophila Trap1 null mutants and describe the genetic analysis of Trap1 function with Pink1 and parkin. We show that loss of Trap1 results in a decrease in mitochondrial function and increased sensitivity to stress, and that its upregulation in neurons of Pink1 mutant rescues mitochondrial impairment. Additionally, the expression of Trap1 was able to partially rescue mitochondrial impairment in parkin mutant flies; and conversely, expression of parkin rescued mitochondrial impairment in Trap1 mutants. We conclude that Trap1 works downstream of Pink1 and in parallel with parkin in Drosophila, and that enhancing its function may ameliorate mitochondrial dysfunction and rescue neurodegeneration in PD.     

Drosophila ref(2)P is required for the parkin-mediated suppression of mitochondrial dysfunction in pink1 mutants

Autophagy is a critical regulator of organellar homeostasis, particularly of mitochondria. Upon the loss of membrane potential, dysfunctional mitochondria are selectively removed by autophagy through recruitment of the E3 ligase Parkin by the PTEN-induced kinase 1 (PINK1) and subsequent ubiquitination of mitochondrial membrane proteins. Mammalian sequestrome-1 (p62/SQSTM1) is an autophagy adaptor, which has been proposed to shuttle ubiquitinated cargo for autophagic degradation downstream of Parkin. Here, we show that loss of ref(2)P, the Drosophila orthologue of mammalian P62, results in abnormalities, including mitochondrial defects and an accumulation of mitochondrial DNA with heteroplasmic mutations, correlated with locomotor defects. Furthermore, we show that expression of Ref(2)P is able to ameliorate the defects caused by loss of Pink1 and that this depends on the presence of functional Parkin. Finally, we show that both the PB1 and UBA domains of Ref(2)P are crucial for mitochondrial clustering. We conclude that Ref(2)P is a crucial downstream effector of a pathway involving Pink1 and Parkin and is responsible for the maintenance of a viable pool of cellular mitochondria by promoting their aggregation and autophagic clearance.     

Biosystematic studies onCapsella bursa-pastoris (Brassicaceae): Enzyme polymorphism in natural populations

The genetic variability of natural populations ofCapsella bursapastoris in North- and Middle-Europe has been estimated by means of enzyme assays. Zymograms of 81 populations have been developed. 17 loci could be identified, and 8 of them can be heterozygous. Genetic variability is greater between populations than within. No correlation between actual population sizes and genetic heterogeneity could be detected. Some electromorphs shift their frequencies proportionally to increasing adversity of climatic conditions, some appear to be constant over the whole area, and others are characterized by an apparently irregular variation pattern. Marginal populations comprise a significantly higher proportion of heterozygous plants than central ones. Apart from this clinal variation pattern, a mosaic pattern, strongly related to habitat conditions, was observed: genetic heterogeneity is greater in more intensively disturbed sites. The pattern of genetic variation in natural populations ofCapsella bursa-pastoris is rather highly influenced by the breeding system.     

Complete genome sequence of Leptotrichia buccalis type strain (C-1013-b)

Leptotrichia buccalis (Robin 1853) Trevisan 1879 is the type species of the genus, and is of phylogenetic interest because of its isolated location in the sparsely populated and neither taxonomically nor genomically adequately accessed family 'Leptotrichiaceae' within the phylum 'Fusobacteria'. Species of Leptotrichia are large, fusiform, non-motile, non-sporulating rods, which often populate the human oral flora. L. buccalis is anaerobic to aerotolerant, and saccharolytic. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first complete genome sequence of the order 'Fusobacteriales' and no more than the second sequence from the phylum 'Fusobacteria'. The 2,465,610 bp long single replicon genome with its 2306 protein-coding and 61 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.     

Variation of development time until flowering in natural populations ofCapsella bursa-pastoris (Cruciferae)

Seed samples were collected from wild populations ofCapsella bursa-pastoris along a transsect from Northern to Southern Europe. Progeny was grown in (a) open-field random block experiments (47 populations) and (b) in growth chambers under five to seven controlled temperature regimes (18 populations). Beginning of flowering was recorded, and great differences between and also within populations are documented. Some populations are extremely heterogenous whereas others are homogenous in this respect. Some biotypes react positively when exposed to lower temperatures, others are inhibited. In many cases specific effects of day- and/or night-temperatures can be inferred. In some progenies begin of flowering is independent of temperature as long as this exceeds the 5:10°C regimen. Altogether,Capsella bursa-pastoris displays definite intraspecific variation in time required until flowering. Adaptations to local ecological conditions are obvious. In addition to a genotypic component pronounced environmental interactions provide the plants with a component of phenotypic plasticity. The degree of modificability apparently varies itself and seems to be controlled by selection; the phenotypic plasticity, therefore, displays adaptive variation patterns, too.Adaptation in Life History Traits of Colonizing Plant Species; Part of a doctoral thesis by the first author.     

Complete genome sequence of Streptobacillus moniliformis type strain (9901)

Streptobacillus moniliformis Levaditi et al. 1925 is the type and sole species of the genus Streptobacillus, and is of phylogenetic interest because of its isolated location in the sparsely populated and neither taxonomically nor genomically much accessed family 'Leptotrichiaceae' within the phylum Fusobacteria. The 'Leptotrichiaceae' have not been well characterized, genomically or taxonomically. S. moniliformis,is a Gram-negative, non-motile, pleomorphic bacterium and is the etiologic agent of rat bite fever and Haverhill fever. Strain 9901(T), the type strain of the species, was isolated from a patient with rat bite fever. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is only the second completed genome sequence of the order Fusobacteriales and no more than the third sequence from the phylum Fusobacteria. The 1,662,578 bp long chromosome and the 10,702 bp plasmid with a total of 1511 protein-coding and 55 RNA genes are part of the Genomic Encyclopedia of Bacteria and Archaea project.     

Scenario of the spread of the invasive species Zaprionus indianus Gupta, 1970 (Diptera, Drosophilidae) in Brazil

Zaprionus indianus was first recorded in Brazil in 1999 and rapidly spread throughout the country. We have obtained data on esterase loci polymorphisms (Est2 and Est3), and analyzed them, using Landscape Shape Interpolation and the Monmonier Maximum Difference Algorithm to discover how regional invasion occurred. Hence, it was apparent that Z. indianus, after first arriving in São Paulo state, spread throughout the country, probably together with the transportation of commercial fruits by way of the two main Brazilian freeways, BR 153, to the south and the surrounding countryside, and the BR 116 along the coast and throughout the north-east.     

Crossing the line: increasing body size in a trans-Wallacean lizard radiation (Cyrtodactylus,Gekkota)

The region between the Asian and Australian continental plates (Wallacea) demarcates the transition between two differentiated regional biotas. Despite this striking pattern, some terrestrial lineages have successfully traversed the marine barriers of Wallacea and subsequently diversified in newly colonized regions. The hypothesis that these dispersals between biogeographic realms are correlated with detectable shifts in evolutionary trajectory has however rarely been tested. Here, we analyse the evolution of body size in a widespread and exceptionally diverse group of gekkotan lizards (Cyrtodactylus), and show that a clade that has dispersed eastwards and radiated in the Australopapuan region appears to have significantly expanded its body size ‘envelope’ and repeatedly evolved gigantism. This pattern suggests that the biotic composition of the proto-Papuan Archipelago provided a permissive environment in which new colonists were released from evolutionary constraints operating to the west of Wallacea.     

Biogeographic variation in genetic variability,apomixis expression and ploidy of St. John's wort (Hypericum perforatum) across its native and introduced range

Background and Aims

St. John''s wort (Hypericum perforatum) is becoming an important model plant system for investigations into ecology, reproductive biology and pharmacology. This study investigates biogeographic variation for population genetic structure and reproduction in its ancestral (European) and introduced (North America) ranges.

Methods

Over 2000 individuals from 43 localities were analysed for ploidy, microsatellite variation (19 loci) and reproduction (flow cytometric seed screen). Most individuals were tetraploid (93 %), while lower frequencies of hexaploid (6 %), diploid (<1 %) and triploid (<1 %) individuals were also identified.

Key Results

A flow cytometric analysis of 24 single seeds per individual, and five individuals per population demonstrated opposite patterns between ploidy types, with tetraploids producing more apomictic (73 %) than sexual (24 %) seed, while hexaploids produced more sexual (73 %) than apomictic (23 %) seed. As hexaploids are derived from tetraploids, these data imply that gene dosage, in addition to the effects of hybridization, influences the switch from apomictic to sexual reproduction. No significant differences in seed production were found between Europe and North America. An analysis of population structure based upon microsatellite profiling demonstrated three major genetic clusters in Europe, whose distribution was reflective of Pleistocene glaciation (e.g. refugia) and post-glacial recolonization of Europe.

Conclusions

The presence of pure and mixed populations representing all three genetic clusters in North America demonstrates that H. perforatum was introduced multiple times onto the continent, followed by gene flow between the different gene pools. Taken together, the data presented here suggest that plasticity in reproduction has no influence on the invasive potential of H. perforatum.     

A revision of the Chinese Trigonalyidae (Hymenoptera,Trigonalyoidea)

The Chinese fauna of the family Trigonalyidae Cresson, 1887, is revised, keyed and fully illustrated for the first time. Eight genera of this family (Bakeronymus Rohwer, 1922, Bareogonalos Schulz, 1907, Jezonogonalos Tsuneki, 1991, re-instated, Lycogaster Shuckard, 1841, Orthogonalys Schulz, 1905, Pseudogonalos Schulz, 1906, Taeniogonalos Schulz, 1906 and Teranishia Tsuneki, 1991) are recorded from China. The genus Ischnogonalos Schulz, 1907, is synonymized with Taeniogonalos Schulz, 1906. In total 40 valid species are recognized. Twenty species are new for science: Jezonogonalos elliptifera sp. n., J. jiangliae sp. n., J. luteata sp. n., J. nigrata sp. n., Lycogaster angustula sp. n., L. flavonigrata sp. n., L. nigralva sp. n., Orthogonalys cheni sp. n., O. clypeata sp. n., O. robusta sp. n., Pseudogonalos angusta sp. n., Taeniogonalos bucarinata sp. n., T. cordata sp. n., T. geminata sp. n., T. sculpturata sp. n., T. triangulata sp. n., T. tricolorisoma sp. n., T. uncifera sp. n., Teranishia crenulata sp. n. and T. glabrata sp. n. Two species are reported new for China: Orthogonalys elongata Teranishi, 1929 and Nanogonalos flavocincta Teranishi, 1929 (renamed to Taeniogonalos subtruncata nom. n.). Seven new synonyms are proposed: Poecilogonalos yuasai Teranishi, 1938, and P. maga taiwana Tsuneki, 1991, of Taeniogonalos taihorina (Bischoff, 1914); Taiwanogonalos minima Tsuneki, 1991, and T. similis Tsuneki, 1991, of Taeniogonalos alticola (Tsuneki, 1991); P. intermedia Chen, 1949, and P. unifasciata Chen, 1949, of Taeniogonalos formosana (Bischoff, 1913). Six taxa are recognised as valid species: Bakeronymus seidakka Yamane & Terayama, 1983, Jezonogonalos laeviceps (Tsuneki, 1991), J. satoi (Tsuneki, 1991), Taeniogonalos alticola (Tsuneki, 1991), T. flavoscutellata (Chen, 1949) and T. gestroi (Schulz, 1908). Five new combinations are made: Jezonogonalos laeviceps (Tsuneki, 1991), comb. n., J. satoi (Tsuneki, 1991), comb. n., Taeniogonalos flavoscutellata (Chen, 1949), comb. n., T. gestroi (Schulz, 1908), comb. n. and T. lachrymosa (Westwood, 1874), comb. n. Lectotypes are designated for Lycogaster violaceipennis Chen, 1949, Poecilogonalos flavoscutellata Chen, 1949, P. rufofasciata Chen, 1949, and P. tricolor Chen, 1949.     

The influence of cone age on the relative longevity of Banksia seeds

Background and Aims

Serotiny is common in the genus Banksia, so any seed collection is likely to be comprised of seeds that were produced in many different years. This study aimed to determine the impact of cone age and degree of serotiny on longevity in ex situ storage.

Methods

Cones of identifiable age classes were collected from three species of Banksia. Seeds were extracted from cones and the degree of serotiny calculated. An estimate of initial viability (K_i), the time for viability to fall by one probit (σ) and the relative longevity of seeds (p₅₀) for each species and cone age class was determined using a comparative longevity test (50 °C, 63 % relative humidity).

Key Results

The degree of serotiny ranged from moderate (7·9) for Banksia attenuata to strong (40·4) for B. hookeriana. Survival curves for all seed age classes within each species could be described by regressions with a common slope (1/σ), but with different values for K_i. The time taken for viability to fall by one probit (σ) could be described by a common value (29·1 d) for all three species.

Conclusions

Differences in seed longevity between cone age classes and species was related to variation in initial viability (K_i) rather than to differences in σ. While targeting the youngest mature seed cohort on a plant will maximize the viability of seeds collected, a wide range of age classes should be collected (but stored as separate cohorts if possible) for quality conservation/restoration seed collections where genetic diversity is important.