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Yellowhorn (Xanthoceras sorbifolium Bunge) is a woody oil species that is widely distributed in northwestern China. To investigate the molecular mechanisms underlying the drought and heat tolerance response of yellowhorn seedlings, changes in protein abundance were analyzed via comparative proteomics. Drought and heat treatment of seedlings was applied in growth chamber, and the leaves were harvested after 7 days of treatment. The total protein was extracted, and comparative proteomic analysis was performed via isobaric tag for relative and absolute quantitation (iTRAQ). The abundance of most of the proteins associated with oxidative phosphorylation, NADH dehydrogenase and superoxide dismutase (SOD) was reduced. The differential proteins associated with photosynthesis enzymes indicated that stress had different effects on photosystem I (PSI) and photosystem II (PSII). After comprehensively analyzing the results, we speculated that drought and heat stress could hinder the synthesis of riboflavin, reducing NADH dehydrogenase content, which might further have an impact on energy utilization. Yellowhorn seedlings relied on Fe-Mn SOD enzymes rather than Cu/Zn SOD enzymes to remove reactive oxygen species (ROS). In addition, heat-shock proteins (HSPs) had significant increase and played a key role in stress response, which could be divided into two categories according to their transcription and translation efficiency. Over all, the results can provide a basis for understanding the molecular mechanism underlying resistance to drought and heat stress in yellowhorn and for subsequent research of posttranslational modification-related omics of key proteins.

Sea buckthorn ( Hippophae L.) is an economically important shrub or small tree distributed in Eurasia. Most of its well-recognized medicinal and nutraceutical products are derived from its berry oil, which is rich in monounsaturated omega-7 (C16:1) fatty acid and polyunsaturated omega-6 (C18:2) and omega-3 (C18:3) fatty acids. In this study, tandem mass tags (TMT)-based quantitative analysis was used to investigate protein profiles of lipid metabolism in sea buckthorn berries harvested 30, 50, and 70 days after flowering. In total, 8626 proteins were identified, 6170 of which were quantified. Deep analysis results for the proteins identified and related pathways revealed initial fatty acid accumulation during whole-berry development. The abundance of most key enzymes involved in fatty acid and triacylglycerol (TAG) biosynthesis peaked at 50 days after flowering, but TAG synthesis through the PDAT (phospholipid: diacylglycerol acyltransferase) pathway mostly occurred early in berry development. In addition, the patterns of proteins involved in lipid metabolism were confirmed by combined quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and parallel reaction monitoring analyses. Our data on the proteomic spectrum of sea buckthorn berries provide a scientific basic for understanding lipid metabolism and related pathways in the developing berries.

Variations in floral traits and floral structures influence plant mating systems. Hibiscus trionum produces large, showy flowers typical of an outcrossing species, yet flowers are autonomously self-pollinated. In this study, we measured floral morphology, breeding system and outcrossing rate estimated by ISSR markers. Results indicate that two types of flowers were observed in H. trionum , and the type I with bigger petals appears to be much more visible to pollinators, demonstrated by than type II flowers with smaller petals. The flowers with hand pollination were closed 1 h earlier than intact flowers, whether they were type I or II. The relationship between the amount of pollen deposited on the stigma and the number of seeds per capsule was highly significant, and 80 or more pollens per flower can make the mean number of seeds (mean = 37) in H. trionum . Delayed selfing in H. trionum did not provide a large contribution to seed production, since reproductive assurance were only 0.025. However, successful reproduction of 72.5% flowers in the absence of pollinators suggested that selfing provides reproductive assurance during seasons, in which pollinators were limiting. The multilocus outcrossing rates in different populations varied from 0.982 to 1.200, with a mean of 1.116. Our data provide an empirical demonstration of a predominantly outcrossing species with potential delayed selfing when pollinators are absent or scarce.

Tea oil camellia (Camellia oleifera) is a perennial evergreen shrub or small tree with multiple uses. Its seed oil contains rich bioactive compounds with powerful nutritional and medicinal values. To improve low seed yield in natural forests of this species, the new grafting technique of high-grafting and change-crown is being widely used. This usually has three grafting methods, inlay graft by separating bark (IGSB), bark xylem graft by cutting stock (BXGCS), and cleft graft (CG). In this research, we (1) investigated growth, development, fruit yield, and traits of trees after high-grafting and (2) tested effects of grafting methods (IGSB, BXGCS, and CG) and times (spring, summer, and autumn) on survival rates. Results indicated that sprouted scions flowered and set fruit in the third year after high-grafting, and grafted trees produced higher oil yields in the fourth year. Both grafting methods and times significantly influence grafting survival rates. The optimal grafting method for this specie...

Yellow horn (Xanthoceras sorbifolia) is a woody deciduous shrub or small tree native to northwest China that has been widely planted for bioactive oil production and ecological restoration. Ten years of field experiments indicate that yellow horn is well adapted to desert and xeric habitats of Liaoning, Inner Mongolia, and Xinjiang, China, and is an excellent prospect for alternative agricultural production and revegetation of arid regions as well as production of bioactive oils. In Horqin Sandy Lands, 7–11 year old unselected mixed lines averaged 152.30 kg/ha seeds, and selected pure lines averaged 1944.89 kg/ha, with average seed oil content of 25% and 34%, respectively. Seeds contain about 90% unsaturated fatty acids (C18:1, C18:2, C18:3, C20:1, C20:2, C20:5, C22:1 and C24:1) and 10% fatty acids comprised primarily of C16:0 and C18:0. Yellow horn seed oils are very high quality with low acid levels of 0.52 mg KOH/g (73% of which is unsaturated C18). Interestingly, the concentration of C24:1, an important bioactive compound is over 2%. Yellow horn is a unique plant species with potentially strong value for both ecological restoration of arid habitats and control of desertification, as well as an important and sustainable producer of high quality bioactive oils, which are used for food, healthy diets, and medical products.

SUMMARYSea buckthorn (Hippophae rhamnoides) is an ecologically and economically important shrub or small tree widely distributed in China, Russia, and Mongolia and its berries are rich in bio-active compounds. Inter-simple sequence repeat (ISSR) markers were used to assess genetic relationships among 78 cultivars and lines of H. rhamnoides ssp. mongolica and hybrids between ssp. mongolica and ssp. sinensis. Thirteen ISSR primers generated 143 bands, 139 (97.2%) of which were polymorphic, with the number of polymorphic bands per primer ranging from 8–17. A low coefficient of gene differentiation (0.0588) indicated that genetic diversity existed mainly within populations. Pairwise genetic similarities among the 78 cultivars and lines ranged from 0.362–0.939. Cluster analysis indicated that these 78 cultivars and lines could be classified into two groups, in good agreement with their taxonomic classification. Euclidean distances and multi-dimensional scaling confirmed the spatial positions of cultivars and l...

Camellia japonica produces different color and bigger flowers, widely being used for gardening green in southern China. However, cultivars were introduced from different regions, but their origin and pedigree information is either not available poorly documented, causing problems in authentication. Many low-yield trees in Camellia oleifera forests have been used as stocks for grafting C. japonica. However, the survival rate of grafts between these two species is related to genetic relationship between stock of C. oleifera and scion of C. japonica. We used simple sequence repeat (SSR) markers to genotype 41 C. japonica cultivars from different regions, as well as nine genotypes of C. oleifera in China. Twenty-one SSR markers generated 438 alleles, with an average of 20.85 alleles per locus. All alleles were used to generate Dice coefficients between two genotypes of all genotypes of these two species. Cluster analysis based on SSR data clustered genotypes showed clustering of genotypes into groups that agreed well with their taxonomic classification and geographic origin. Cultivar 'Damaonao' was a large tree with flowers of composite color, and showed the most genetic distance from other C. japonica cultivars and C. oleifera genotypes in the cluster analysis. The cultivars of C. japonica are distinct from genotypes of C. oleifera. The results for cultivars of C. japonica also revealed the presence of different cultivars with the same name, and identical cultivars but with a different name. SSR profiles can improve C. japonica germplasm management, and provide potential determine correlations between genetic relationship and graft compatibility among scions of C. japonica and genotypes of C. oleifera.

Bioactive oils extracted from sea buckthorn (Hippophae rhamnoides) berries contain highly nutritional and medicinal compounds; however, the oil contents of sea buckthorn berries are very low. Thirteen inter-simple sequence repeat (ISSR) primers were used to identify markers associated with oil content of dry pulp in 51 cultivars and lines, which clustered into three major groups based on 137 polymorphic markers. Dry pulp oil contents in 45 cultivars and lines in Group I ranged from 6.6 to 33.1%; these accessions belonged to H. rhamnoides ssp mongolica and its hybrids with H. rhamnoides ssp sinensis. Three lines (H. rhamnoides ssp mongolica) in Group II had high dry pulp oil contents (33.7 to 37.5%), whereas three lines of hybrids in Group III had low dry pulp oil contents (10.9 to 17.5%). The dry pulp oil content of H. rhamnoides ssp mongolica (27.2 ± 0.9%) was higher than that of hybrids (12.0 ± 1.2%) (P < 0.01). Four ISSR markers (881340, 8251000, 817380, and 8071100) had positive association with high dry pulp oil content (P < 0.01) using stepwise multiple regression analysis. The use of these ISSR markers is a potential strategy to select genotypes with high dry pulp oil content and suitable parental combinations for improvement of sea buckthorn berries.

Salt marshes constitute major sinks for heavy metal accumulation but the precise impact of salinity on heavy metal toxicity for halophyte plant species remains largely unknown. Young seedlings of Kosteletzkya virginica were exposed during 3 weeks in nutrient solution to Cd 5 µM in the presence or absence of 50 mM NaCl. Cadmium (Cd) reduced growth and shoot water content and had major detrimental effect on maximum quantum efficiency (F(v) /F(m) ), effective quantum yield of photosystem II (Y(II)) and electron transport rates (ETRs). Cd induced an oxidative stress in relation to an increase in O(2) (•-) and H(2) O(2) concentration and lead to a decrease in endogenous glutathione (GSH) and α-tocopherol in the leaves. Cd not only increased leaf zeatin and zeatin riboside concentration but also increased the senescing compounds 1-aminocyclopropane-1-carboxylic acid (ACC) and abscisic acid (ABA). Salinity reduced Cd accumulation already after 1 week of stress but was unable to restore shoot growth and thus did not induce any dilution effect. Salinity delayed the Cd-induced leaf senescence: NaCl reduced the deleterious impact of Cd on photosynthesis apparatus through an improvement of F(v) /F(m) , Y(II) and ETR. Salt reduced oxidative stress in Cd-treated plants through an increase in GSH, α-tocopherol and ascorbic acid synthesis and an increase in glutathione reductase (EC 1.6.4.2) activity. Additional salt reduced ACC and ABA accumulation in Cd+NaCl-treated leaves comparing to Cd alone. It is concluded that salinity affords efficient protection against Cd to the halophyte species K. virginica, in relation to an improved management of oxidative stress and hormonal status.

Sea buckthorn (Hippophae L.) is a woody perennial shrub or small tree whose berries are rich in bioactive compounds with powerful nutritional and medicinal properties. Untargeted 1H nuclear magnetic resonance (NMR) spectroscopy and principal component analysis (PCA) were used to characterize the metabolic profile of berry quality. There was strong separation in the NMR signal intensity of bioactive compounds between pulp and seeds, such as amino acids [gamma-aminobutyric acid (GABA), aspartate, glutamate, theanine, and proline], organic acids (citrate, succinate, malate, acetate, quinate, and heriguard), and carbohydrates (sucrose, fructose, glucose, and melibiose). Sea buckthorn cultivars could be clearly separated into two groups using principal component analysis (PCA) based on NMR spectroscopy of bioactive compounds in the pulp and seeds. Several metabolic compounds such as sugar, organic acids, and amino acids could serve as biomarkers for prediction of berry quality and for classification of germplasm collections. This dataset provides potential information concerning the mechanisms of berry quality formation and contributes to increasing the breeding efficiency of sea buckthorn quality improvement.

Reproductive assurance is a widely accepted explanation for the evolution of selfing, although theory suggests that an evolutionarily stable mixed mating strategy does not maximize seed production. We present a correlation analysis involving 28 species representing 23 families showing that selfing can evolve independently of inbreeding depression. We discuss the cost-benefit trade-off of selfing, in particular the incongruence of whether delayed selfing provides reproductive assurance in 22 species representing 14 families, in which pollen and seed discounting are minimized when pollinators or mates are scarce. Reproductive assurance, in response to frequent pollinator failure, can be reconciled with an evolutionarily stable mixed mating system contributed to by delayed selfing, which is still advantageous even if there is strong inbreeding depression.

Sea buckthorn is a berry crop with multiple uses. The berries are highly appreciated for their unique taste but are also very rich in bioactive compounds with powerful nutritional and medicinal values. In addition, the plants grow well under adverse conditions, and are often used to fight soil erosion. Utilization of sea buckthorn has therefore increased around the world but serious problems have, nevertheless, been encountered due to drought, salinity, diseases and insect pests. This review covers important aspects of sea buckthorn research, such as heritable and environmentally induced variation in biochemical compounds, causes and effects of the devastating dried-shrink disease, susceptibility to insect pests, methods for conventional breeding, and the utilization of DNA markers for taxonomical and population genetic analyses, and for investigating the inheritance of quality and resistance traits. We also present possibilities to implement innovative biotechnological breeding methods, especially metabolite profiling and MAS/GRC-based markers, for fast and efficient development of elite genotypes with specific nutritional- and health-related bioactive compounds and strong resistance to biotic and abiotic stress.

Hydroponic experiments were carried out using seedlings of the wetland halophyte species Kosteletzkya virginica (L.) Presl. exposed to 10 μM Cd or 100 μM Zn in the absence or presence of 50 mM NaCl. Interaction between salinity and heavy metals was analysed in relation to plant growth, water status and tissue ion contents (Na, K and Ca). Results showed a strong inhibition effect of Cd on leaf emergence, lateral branch development and leaf expansion. Heavy metals induced a significant decrease in plant dry weight, water content, osmotic potential (Ψ S) and leaf water potential (Ψ w). Cadmium and Zn accumulated to higher extent in the roots than in the shoots. Cadmium increased the leaf K concentration while Zn had an opposite effect. Salinity strongly reduced Cd uptake and translocation from roots to shoots: it mitigated the Cd impact on lateral branch emergence but had no effects on plant dry weight and water status. Cadmium drastically reduced Na translocation in salt-treated plants while Zn increased it. It is concluded that complex interactions exist between heavy metals and monovalent cations in salt conditions and that Cd and Zn display contrasting behaviour in this respect. Stress-induced modification of ion content did not fully explain growth inhibition in Kosteletzkya virginica.

Kosteletzkya virginica (L.) Presl. is a perennial wetland halophyte which could be exposed to heavy metals in polluted salt marsh environments. In order to investigate the interaction between salinity (50 mM NaCl) and heavy metal, young plants were exposed in hydroponic culture to 10 μM Cu in the presence or absence of 50 mM NaCl. Copper strongly inhibited the leaf emergence and lateral branch development as well as leaf expansion, and induced a significant decrease in plant dry weight (DW), water content (WC), osmotic potential (Ψs) and leaf water potential (Ψw). Copper treated plants accumulated significantly higher level of Cu in the roots than in the shoots although Cu intake rates decreased with the duration of stress exposure. Additions of NaCl in the absence of Cu excess had no detrimental impact on plant growth. In the presence of Cu excess, NaCl decreased Cu accumulation in roots and stems but had no positive impact on plant growth. Copper induced a large decrease in K concentration in roots and stems as well as a decrease in Ca concentration in the leaves. The impact of Cu and NaCl appeared to be additive on leaf Ψs and leaf quaternary ammonium compounds concentrations. It is concluded that K. virginica exhibits a high bioconcentration factor for Cu which could be, at least partly, responsible for its sensitivity to this toxic element. The impact of stress on K and Ca homeostasis is discussed in relation to ion distribution and presence of mucilage in the plant.

The evolution of floral movement responding to pollination environments has long intrigued biologists. This has been mostly demonstrated in different species, but has as yet few explanations at the family level. Style curvature occurs in 23 species of eight genera among our observed and surveyed 52 species of 13 genera in the Malvaceae. To analyze the origin of style curvature in these species, we mapped this and correlated characters onto molecular phylogenetic trees that were constructed using the combination of the chloroplast DNA sequences of ndhF and the rpl16 intron. The results showed that style curvature evolved at least five times in species with herkogamous flowers. The occurrence of style curvature was associated with a shift to annual or perennial herbs with herkogamous flowers, which have similar ecological distributions with unpredictable pollinator environments. Style curvature appears to have evolved to facilitate delayed selfing if outcrossing fails under unpredictable pollination conditions.

Since Darwin observed the reconfiguration of pollinia in orchards and referred to it as a function to reduce self-pollination, diverse floral movements have been investigated and various hypotheses have been proposed to explain their adaptive significance. However, adaptive significance of floral movement in some species has yet to be fully explained. Increasing evidence suggests that some floral movements, which have previously been considered as a mechanism to avoid self-pollination, may act as a mechanism to reduce intrafloral male-female interference. In this review, we first explore insect-induced floral movement—such as secondary pollen presentation—that enhances the efficiency and accuracy of pollination. Secondly, we outline the active movements of different floral structures of pistil (style), stamen (filament, anther, pollen), and corolla, such as flexistyly, pollen sliding and catapulting, and anther rotation. Thirdly, we introduce movement herkogamy, which makes herkogamy decrease or increase ...

Global warming is one of the most serious challenges facing us today. It may be linked to the increase in atmospheric CO2 and other greenhouse gases (GHGs), leading to a rise in sea level, notable shifts in ecosystems, and in the frequency and intensity of wild fires. There is a strong interest in stabilizing the atmospheric concentration of CO2 and other GHGs by decreasing carbon emission and/or increasing carbon sequestration. Biotic sequestration is an important and effective strategy to mitigate the effects of rising atmospheric CO2 concentrations by increasing carbon sequestration and storage capacity of ecosystems using plant photosynthesis and by decreasing carbon emission using biofuel rather than fossil fuel. Improvement of photosynthetic carbon assimilation, using transgenic engineering, potentially provides a set of available and effective tools for enhancing plant carbon sequestration. In this review, firstly different biological methods of CO2 assimilation in C-3, C-4 and CAM plants are introduced and three types of C-4 pathways which have high photosynthetic performance and have evolved as CO2 pumps are briefly summarized. Then (i) the improvement of photosynthetic carbon assimilation of C-3 plants by transgenic engineering using non-C-4 genes, and (ii) the overexpression of individual or multiple C-4 cycle photosynthetic genes (PEPC, PPDK, PCK, NADP-ME and NADP-MDH) in transgenic C-3 plants (e. g. tobacco, potato, rice and Arabidopsis) are highlighted. Some transgenic C-3 plants (e. g. tobacco, rice and Arabidopsis) overexpressing the FBP/SBPase, ictB and cytochrome C-6 genes showed positive effects on photosynthetic efficiency and growth characteristics. However, over the last 28 years, efforts to overexpress individual, double or multiple C-4 enzymes in C-3 plants like tobacco, potato, rice, and Arabidopsis have produced mixed results that do not confirm or eliminate the possibility of improving photosynthesis of C-3 plants by this approach. Finally, a prospect is provided on the challenges of enhancing carbon assimilation of C-3 plants using transgenic engineering in the face of global warming, and the trends of the most promising approaches to improving the photosynthetic performance of C-3 plants.

Recent works have shown that mixed mating systems often evolve despite strong inbreeding depression and reproductive assurance, which is one of the widely accepted explanations for the evolution of selfing. However, there have been few empirical studies on the relationship between mixed mating and reproductive assurance in perennial plants. In the herbaceous perennial, Kosteletzkya virginica , delayed selfing induced from context-dependent style curvature offers reproductive assurance, and adverse weather conditions significantly reduce pollinator visitation rates. In this study, our goals were (i) to experimentally evaluate pollinator failure rate, reproductive assurance, selfing rate and the relationships between them, and (ii) to measure inbreeding depression across multiple growth seasons. Results indicate that both population selfing rates and reproductive assurance are significantly and positively correlated with field estimates of pollinator failure rates, and there is a strong relationship between selfing rates and reproductive assurance. Inbreeding depression across multiple growth seasons ranged from 0.621 to 0.665, and there were no significant differences among different seasons. Our data demonstrates that a mixed mating system is beneficial because frequent pollinator failure has allowed reproductive assurance to evolve through delayed selfing which minimizes the risk of seed discounting and is still advantageous despite high inbreeding depression.

A highly efficient process intensification strategy was developed to enhance the taxuyunnanine C (Tc) production in Taxus chinensis (T. chinensis) by combining repeated elicitation with a synthesized jasmonate analog, 2,3-dihydroxypropyl jasmonate (DHPJA), sucrose feeding and in situ adsorption. Suspension cultures of a high Tc-producing cell line of T. chinensis were supplemented twice, on day 7 and day 12, with 100 μM DHPJA. The cultures were also supplemented by feeding 20 g sucrose/l and 100 g Ambelite XAD-7/l on day 7. This strategy had a synergistic effect on Tc synthesis, causing a significant increase in the Tc yield to 1,715.13 ± 124.12 mg/l on day 21. The yield was 3.28-fold above that produced by repeated DHPJA elicitation combined with sucrose feeding. When XAD-7 was replaced by Amberlite XAD-7 HP, the result was slightly different. The highest Tc yield of 1,728.84 ± 50.37 mg/l was achieved on day 27. The Tc yield achieved here is greater than twice the highest yield reported previously, the sole reported taxoid production yield above the gram per liter level. Given the pharmaceutical importance of taxoids, the results of this study will greatly contribute to the potential industrial production of Tc and other taxoids by plant cell cultures.

It is more important to improve the salt tolerance of crops in a salinized world with the situations of increasing populations, declining crop yields, and a decrease in agricultural lands. Attempts to produce salt-tolerant crops have involved the manipulation of existing crops through conventional breeding, genetic engineering and marker-assisted selection (MAS). However, these have, so far, not produced lines growing on highly saline water. Hence, the domestication of wild halophytes as crops appears to be a feasible way to develop agriculture in highly saline environments. In this review, at first, the assessment criteria of salt tolerance for halophytes are discussed. The traditional criteria for the classification of salinity in crops are less applicable to strong halophytes with cubic growth curves at higher salinities. Thus, realistic assessment criteria for halophytes should be evaluated at low and high salinity levels. Moreover, absolute growth rather than relative growth in fields during a crop's life cycle should be considered. Secondly, the use of metabolomics to understand the mechanisms by which halophytes respond to salt tolerance is highlighted as is the potential for metabolomics-assisted breeding of this group of plants. Metabolomics provides a better understanding of the changes in cellular metabolism induced by salt stress. Identification of metabolic quantitative trait loci (QTL) associated with salt tolerance might provide a new method to aid the selection of halophyte improvement. Thirdly, the identification of germplasm-regression-combined (GRC) marker-trait association and its potential to identifying markers associated with salt tolerance is outlined. Results of MAS/linkage map-QTL have been modest because of the absence of QTLs with tight linkage, the non-availability of mapping populations and the substantial time needed to develop such populations. To overcome these limitations, identification by GRC-based marker-trait association has been successfully applied to many plant traits, including salt tolerance. Finally, we provide a prospect on the challenges and opportunities for halophyte improvement, especially in the integration of metabolomics- and GRC-marker-assisted selection towards new or unstudied halophyte breeding, for which no other genetic information, such as linkage maps and QTL, are available.

Sea buckthorn ( Hippophae L.) is a woody, dioecious plant that can be grown in dry and poor soil conditions. It has recently received world-wide attention as a new berry crop with a very high nutritional value and unique medicinal properties, as well as a means of combating soil erosion. A major problem is, however, dried-shrink disease (DSD), which destroys sea buckthorn plants and halts commercial production. In this study, we investigated symptoms and pathogenicity of DSD, isolated and identified pathogens using a combination of morphology and ITS sequences, and evaluated the disease index (DI) of different cultivars in the field. DSD infection causes isolated yellowing of plant tissues, and as the disease develops the bark putresces, dries and shrinks, and finally the plant dies. DSD infects older plants (>3 years), often at the plant base. Death of plant parts above the infected area does not influence root vitality, and a new plant can therefore be regenerated. Combining morphological characters and ITS sequences, we isolated and identified four fungal pathogens causing DSD, including Fusarium acuminatum , F. oxysporum , Fusarium camptoceras and Phomopsis spp. DI values for 27 cultivars ranged from 0 to 10.4. About half of the cultivars were regarded as resistant (DI 6.7). Cultivar ‘Zhongguoshaji’ (DI = 4.2) showed an intermediate level of DSD resistance. Our data provides basic information for further studies of the mechanism of pathogenicity, and for breeding of DSD-resistant cultivars.

Curvature of un-pollinated styles towards the anthers in the Malvaceae has been interpreted as different adaptive mechanisms, presenting a challenging problem for evolutionary biologists. We have surveyed different species of this family to determine in which style curvature occurs, and to determine its possible functional roles. Two distinct types of style curvature occur in 18 species distributed in eight genera of four tribes: Type I, before pollen shedding, occurs in species of the Malvavisceae, Ureneae, and Hibisceae tribes, which have highly receptive stigmas and viable pollen when curvature brings stigmas into contact with anthers; and Type II, after pollen shedding, only appears in the protandrous species of the Malveae tribe. Curvature is often associated with annual and perennial herbs. We conclude that the adaptive significance of style curvature in the Malvaceae includes delayed selfing, promotion of outcrossing, and reduction in intrafloral male–female interference, even if the frequency of two or three of these occurs in one species only. This diversity provides model plants and the opportunity for determining the evolution, relative importance, and harmony mechanism of different adaptive significance, especially when two or three functions occur simultaneously in one floral movement of one species (e.g., Kosteletzkya virginica).

Mucilage is thought to play a role in salinity tolerance in certain halophytic species by regulating water ascent and ion transport. The localization and composition of mucilage in the halophyte Kosteletzkya virginica was therefore investigated. Plants were grown in a hydroponic system in the presence or absence of 100mM NaCl and regularly harvested for growth parameter assessment and mucilage analysis with the gas liquid chromatography method. NaCl treatment stimulated shoot growth and biomass accumulation, had little effect on shoot and root water content, and reduced leaf water potential (Psi(w)), osmotic potential (Psi(s)) as well as stomatal conductance (g(s)). Mucilage increased in shoot, stems and roots in response to salt stress. Furthermore, changes were also observed in neutral monosaccharide components. Levels of rhamnose and uronic acid increased with salinity. Staining with a 0.5% alcian blue solution revealed the presence of mucopolyssacharides in xylem vessels and salt-induced mucilaginous precipitates on the leaf abaxial surface. Determination of ion concentrations showed that a significant increase of Na(+) and a decrease of K(+) and Ca(2+) simultaneously occurred in tissues and in mucilage under salt stress. Considering the high proportion of rhamnose and uronic acid in stem mucilage, we suggest that the pectic polysaccharide could be involved in Na(+) fixation, though only a minor fraction of accumulated sodium appeared to be firmly bound to mucilage.

Sea buckthorn ( Hippophae L.) is a woody, outcrossing dioecious pioneer plant, being widely planted as a new berry crop with rich nutritional and medicinal compounds, as well as a means of prevention of soil erosion. Inter simple sequence repeat (ISSR) markers were generated in 219 plants of 40 cultivars from China and other countries, representing two species of Hippophae salicifolia and Hippophae rhamnoides that includes two subspecies (ssp. mongolica and ssp. rhamnoides ) and intraspecific hybrids between ssp. mongolica and ssp. sinensis . Fifteen selected ISSR primers generated 385 bands with an average of 25.6 bands per primer. Thirty hundred and eighty-five bands were used to generate a Dice's coefficient matrix of pairwise comparisons between individual ISSR profiles. Cluster analysis based on this matrix showed clustering of plants into groups which was in good agreement with their taxonomic classification. The results also revealed the presence of different cultivars with the same name, identical cultivars but with a different name and the genetic relationship of cultivars with unknown parentage to those with known parentage. Our data will be helpful in collection and conservation of sea buckthorn germplasm and potential hybrid strategy for breeding.

The common sea buckthorn or seaberry (Hippophae rhamnoides) is important environmentally, commercially, and as a new berry crop. Some morphological differences among mother plants and lines obtained by cuttings often lead a purchaser to question if the propagated plantlets are true-to-name cultivars. Intersimple sequence repeat (ISSR) markers were employed to assess the genetic stability of lines obtained by cuttings of four H. rhamnoides cultivars and the genetic relationships among them. Fifteen ISSR primers generated 174 bands among the 35 samples of four cultivars, 158 of which (90.8%) were polymorphic. Percentages of polymorphic and unique bands between mother plant and propagated plantlets ranged from 53.21% to 77.17% and from 7.09% to 13.76%, respectively. Cluster analysis based on ISSR data indicated that at a Jaccard coefficient of 0.78, mother plant and lines obtained by cuttings for each cultivar were grouped into different subclusters, respectively, which could be further clustered into differ...

Herkogamy may act as a mechanism to reduce interference between the reproductive functions of female and male organs, but too great a distance between stigmas and anthers may also decrease the outcross pollen transfer and male and female fitness. Our goal was to quantify the effect of movement herkogamy in Kosteletzkya virginica on reproductive success and its contribution to pollen receipt and reproductive assurance. Field investigations and hand-pollination experiments were performed to test: (1) the relationship between herkogamy before curvature of un-pollinated lobes and reproductive success under pollinator exclusion; (2) the contribution of movement herkogamy to pollen receipt; and (3) the relationship between pollen load and seed set. We noted that variation in herkogamy before curvature of un-pollinated lobes did not affect the outcome of autogamous self-pollination measured by fruit set and mean number of seeds per fruit. Under natural conditions, 39% of pollen grains deposited per flower were from autogamous self-pollination via movement herkogamy resulting in contact between anthers and stigmas. The relationship between the amount of pollen grains and the number of seeds per capsule was highly significant. Flowers producing four or five seeds received more pollen grains than those producing only one seed. Our data provides experimental evidence that movement herkogamy, which decreases the separation between anthers and stigmas and results in delayed self-pollination, contributes to pollen receipt and further enhances seed set when pollinators are scarce or absent.

Sea buckthorn (Hippophae L.) is an economically important, globally distributed shrub with unique biochemical properties. This long-juvenile and long-lived woody plant can be more difficult to cultivate than other crop plants. Dried-shrink disease is a dangerous pathogen that destroys sea buckthorn and halts commercial production. We estimated variability of ISSR molecular markers in 52 accessions of 16 sea buckthorn varieties and lines to seek markers associated with dried-shrink resistance and help identify potential breeding varieties and lines. Fifteen ISSR primers generated 346 bands, with an average of 23 bands per primer. Genetic similarities (Jaccard coefficient) between pairs of accessions ranged from 0.216 to 0.781. At a Jaccard coefficient of 0.39, the dendrogram generated with 342 polymorphic bands clustered 51 accessions of H. rhamnoides into five groups and one H. salicifolia isolate. Four ISSR markers (887190, 835700, 809290, and 811280) were significantly correlated with resistance to dried-shrink disease (P < 0.001). These markers provide a potential method for breeding programs that select lineages resistant to dried-shrink disease, especially when no other genetic information such as linkage maps and Quantitative Trait Loci are available.

Kosteletzkya virginica, a perennial dicot halophytic species of the Malvaceae, is native to American salt marsh. It was introduced into China as a potential species to improve coastal wetlands and to develop ecologically sound saline agriculture. K. virginica adapts excellently to the tidal-flat habitats in China's east coast, with multiple eco-benefits; in particular, its seed oil could be used to produce biodiesel. The purpose of this study was thus to develop a standardized protocol to induce a high frequency of callus and subsequent plantlet regeneration system for a K. virginica breeding program with the final objective of applying transgenic techniques to improve seed oil yield. The embryonic axes of K. virginica were used as explants for callus induction, shoot induction from the callus and then adventitious root induction from the shoots on nine culture media with different hormone combinations. The best results were achieved on the following media: (1) 93.94% callus induction on MS medium supplemented with 1.0 mg L−1 indole-3-acetic acid (IAA), 0.3 mg L−1 kinetin, 30 g L−1 sucrose and 8 g L−1 agar; (2) 65.83% shoot induction on 1/2MS medium supplemented with 0.1 mg L−1 IAA, 0.5 mg L−1 zeatin, 30 g L−1 sucrose and 8 g L−1 agar; (3) 96.67% rooting on MS medium containing 30 g L−1 sucrose and 8 g L−1 agar. The survival rate of plantlets by organogenic regeneration was 85% after being transplanted into potting soil in flowerpots and placed in the greenhouse. This experiment indicates that we established successful callus induction and plant regeneration protocols for K. virginica.

Delayed selfing is a reproductive strategy that can increase mating opportunities and provide reproductive assurance in the absence of pollinators. When external pollination fails to occur in the herbaceous perennial, Kosteletzkya virginica, the styles curve downward to bring anthers into contact with the stigmal lobes, resulting in delayed selfing. Our goal was to evaluate experimentally the effects of weather conditions on pollinator activity, style curvature, and plant fitness. We discovered that adverse weather conditions significantly reduced pollinator visitation rates, and increased the incidence of style curvature, which resulted in delayed selfing. Furthermore, elimination of delayed selfing by experimental manipulation reduced fruit and seed set compared to non-emasculated flowers, even under adverse weather conditions. Offspring produced through selfing were similar to outcrossed progeny in the majority of fitness traits measured, and inbreeding depression was limited. Our study demonstrates that context-dependent style curvature promotes delayed selfing and provides reproductive assurance in the absence of pollinators, with minimal loss of progeny performance through inbreeding depression.

Mixed mating systems often evolve despite strong inbreeding depression, but there have been few experimental tests of this observation. Kosteletzkya virginica, a perennial dicot halophytic species of the Family Malvaceae, is native to brackish portions of coastal tidal marsh in the United States of America and was introduced into China in 1993. Pollination of K. virginica occurs through insect vectors and by delayed self-pollination via stylar movement. In the same two naturalized populations of K. virginica during 2005–2007, we measured (i) inbreeding depression across a range of life-cycle stages, (ii) pollination failure rate, and (iii) selfing rate estimated by AFLP markers. Results indicate that inbreeding depression values for the two naturalized populations during 2005–2007 ranged from 0.620 ± 0.036 to 0.656 ± 0.032, and mean inbreeding depression was 0.640 ± 0.006. Pollinator failure rates at the two naturalized K. virginica populations during 2005–2007 ranged from 0.091 ± 0.039 to 0.174 ± 0.061, and selfing rate ranged from 0.247 ± 0.018 to 0.468 ± 0.031. Population selfing rates are significantly and positively correlated with field estimates of pollinator failure (P = 0.008

Kosteletzkya virginica, a perennial halophyte, is native to the American salt marsh. It was introduced into China as a potential species to improve tideland and develop ecologically sound saline agriculture. The experimental results in the fields over 10 years indicated that K. virginica adapts excellently to the tidal flat habitats in China's east coast, with multiple ecobenefits such as landscape beautification, revegetation and providing food source for targeted wildlife or migratory birds. Seed yields of unselected mixed and bred lines were 621kg/ha and 957kg/ha, respectively. Oil contents in the seeds of the unselected mixed and bred lines were 17.536% and 20.64%, respectively. The unsaturated fatty acids (70.134%) in the seed oil predominated over the saturated ones (29.866%). Seed oil of K. virginica could produce a high quality biodiesel, of which the unsaturated C18 content of the main part was about 68.62% and sulfur content was 0.0003%. Cetane No. and flash point were both higher than those of diesel fuel, and rust class of steel was lower than that of diesel fuel. These indicate that K. virginica could be used as an agroecoengineering species for alternative agricultural production and for revegetation of salt-affected tidal flats in China's east coast.

Sea buckthorn (Hippophae rhamnoides) is important environmentally and as a new commercial berry crop. Fourteen cultivars of sea buckthorn from China, Russia and Mongolia were evaluated for genetic relationships using RAPD data. Nine random primers were used to generate 114 RAPD markers by PCR. Among them, 103 (90.35%) were polymorphic. The genetic similarity ranged from 0.45 to 0.80 with a mean of 0.67. Genetic distance ranged from 0.23 to 0.80 with a mean of 0.40. Cluster analysis identified Zhongguoshaji from China (H. r. subsp. sienses) as the most genetically distinct cultivar. Hongguo (H. r. subsp. sienses), Zhongguoyou (H. r. subsp. sienses), the hybrid Liaohuerhao from China, Zeliang and Huoguang from Russia (H. r. subsp. mongolica) were clustered more distantly. The seven cultivars from Russia and Mongolia (H. r. subsp. mongolica) and the hybrid Liaohuyihao from China were grouped into two main clusters. Cluster I contained Chengsi, Liaohuyihao, Xiangyang, Chuyi and Wulangemu. Cluster II consists of Nuyou, Hongyun and Aleiyi. Data provide a scientific basis for selection and management of germplasm collections and crossing strategies for sea buckthorn.

Kosteletzkya virginica (L.) Presl. is a perennial dicot halophytic species, that grows in brackish portions of coastal tidal marshes of the mid-Atlantic and southeastern United States. New saline mudflats have been increasing every year in Northern Jiangsu, China. In 1993, we introduced K. virginica (L.) into China from the Halophyte Biotechnology Center (University of Delaware, USA) as a potential species to improve the soil and develop ecologically sound saline agriculture. Our nearly 10 years of experimental research, both in a test garden and in the field, indicated that K. virginica adapts excellently to the heavy saline soils of Jiangsu Province, China. The average seed yield of K. virginica in 2001 at Yancheng was 638 kg/ha from 1-year old seedlings. There were significant variations among individuals from the unselected population of K. virginica on growth, quality, and seed yield traits. There is great potential to increase the seed yield if superior clones are selected. The seed yield of 35 selected individuals was six times greater than that of the average. Four growth traits of K. virginica were found to have a significant correlation with seed yield. However, there was no strong positive or negative correlation among seed quality traits. The mean seed weight and the germination ratio of the 35 selected individuals of K. virginica were 16.36 ± 0.32 g and 76.11 ± 1.82%, respectively. The percentage content of oil and crude protein in the seeds was 11.28 ± 0.67 and 8.17 ± 0.19%, respectively. The percentage of seed vigor of the selected individuals was 99%, as determined by soft X-ray radiography. © 2004 Elsevier B.V. All rights reserved.

Breeders have long been interested in understanding the biological function and mechanism of xero-halophytes and their ability for growth in drought-stricken and salinized environments. However, the mechanisms in response to stress have been difficult to unravel because their defenses require regulatory changes to the activation of multiple genes and pathways. Metabolomics is becoming a key tool in comprehensively understanding the cellular response to abiotic stress and represents an important addition to the tools currently employed in genomics-assisted selection for plant improvement. In this review, we highlight the applications of plant metabolomics in characterizing metabolic responses to salt and drought stress, and identifying metabolic quantitative trait loci (QTLs). We also discuss the potential of metabolomics as a tool to unravel stress response mechanisms, and as a viable option for the biotechnological improvement of xero-halophytes when no other genetic information such as linkage maps and QTLs are available, by combining with germplasm-regression-combined marker-trait association identification.

Multi-mechanisms simultaneously deployed by the flowers of Kosteletzkya virginica were described. It not only first promote outcrossing in floral structures (approach herkogamy and protogyny of some flowers), but also then lead to achieve self-pollination by skillfully using multi-mechanisms (active style movement and corolla closing) when pollinators are scarce or absent. The interesting mechanisms add to the diversity of pollination strategies of flowering plants.