Phylogeography and divergence in the chloroplast genome of Western Australian Sandalwood (Santalum spicatum)

Western Australian sandalwood (Santalum spicatum) is widespread throughout Western Australia across the semiarid and arid regions. The diversity and phylogeographic patterns within the chloroplast genome of S. spicatum were investigated using restriction fragment length polymorphism analysis of 23 populations. The chloroplast diversity was structured into two main clades that were geographically separated, one centred in the southern (semiarid region) and the other in the northern (arid) region. Fragmentation due to climatic instability was identified as the most likely influence on the differentiation of the lineages. The lineage in the arid region showed a greater level of differentiation than that in the southern region, suggesting a higher level of gene flow or a more recent range expansion of sandalwood in the southern region. The phylogeographic pattern in the chloroplast genome is congruent with that detected in the nuclear genome, which identified different genetic influences between the regions and also suggested a more recent expansion of sandalwood in the southern region.     

Somatic embryogenesis and plantlet formation in Santalum album and S. spicatum

A reproducible system for somatic embryogenesis and plantlet formation of sandalwood has been developed. A high frequency (100%) of somatic embryos were induced directly from various explants in MS (Murashige and Skoog, 1962) medium with thidiazuron (1 or 2 M) or indirectly in medium containing 2,4-D plus thidiazuron. Within 8 weeks, white globular somatic embryos or friable embryogenic tissue developed on cultured explants. In S. album the globular somatic embryos were transferred to MS medium supplemented with IAA (6 M) and kinetin (1 and M) where they developed further, multiplied and maintained friable embryogenic tissue. After 15-30 d, mature somatic embryos (1-2 mm) with well-developed cotyledons were separated and subcultured on to medium containing GA3 (6 M) for germination. Once germinated, elongated somatic embryos (10-20 mm long) grew further in MS supplemented with lower GA3 (3 M). In S. spicatum, the addition of casein hydrolysate and coconut milk was necessary for plantlet development from somatic embryos. From histological studies, it appeared that primary somatic embryos arose from single cells or had a multicellular origin from the epidermis or cortical parenchyma. Secondary somatic embryos and friable embryogenic tissue differentiated from groups of proembryogenic cells from a superficial layer of the primary somatic embryos.Keywords: Santalum album, Santalum spicatum, somatic embryogenesis, histological studies.      

Seed caching by woylies Bettongia penicillata can increase sandalwood Santalum spicatum regeneration in Western Australia

Abstract The role a small marsupial, the woylie Bettongia penicillata, might play in the recruitment and regeneration of Western Australian sandalwood Santalum spicatum through its seed caching behaviour was investigated in this study. To determine the fate of the seeds, cotton thread was attached to the seeds and the trail followed. A total of 25 seed caches were located. All of the seeds were found in separate caches, which was consistent with scatter‐hoarding behaviour. The average distance from the source of the seeds to the cache was 43.1 m ± 5.8 m at Dryandra woodland and 29.1 m ± 3.8 m at Karakamia sanctuary. The mean cache depth was 4.3 cm ± 0.2 cm at Dryandra woodland compared with 4.6 cm ± 0.3 cm at Karakamia sanctuary. Significantly more seedlings and saplings grew away from sandalwood trees at sites where woylies were present than at sites with no woylies. In contrast, significantly more seedlings and saplings grew under adult sandalwood trees at the site without woylies than where they were present, although there were significantly lower rates of recruitment and sandalwood regeneration at these sites. In addition, significantly more whole, undisturbed sandalwood seeds were found under the parent trees at the woylie‐free site than at the site with woylies. These findings strongly suggest that little seed dispersal or regeneration of sandalwood occurs in the absence of woylies. Through scatter‐hoarding, woylies have the potential to disperse and cache sandalwood seeds away from the source and significantly alter the subsequent regeneration of sandalwood. Furthermore, by caching seeds large distances away from a source, woylies could modify the distribution of sandalwood in an area.     

Plantlet Regeneration from Encapsulated and Non-encapsulated Desiccated Somatic Embryos of a Forest Tree: Sandalwood (Santalum album L.)

Somatic embryos obtained from embryogenic tissues of sandalwood (Santaium album) were grown on White’s medium containing abscisic acid, (ABA, 1.89, 3.78 or 18.92 μM) and various concentrations of sucrose (87.6 to 350.4 mM) to induce maturation. The embryos were isolated and desiccated for 10, 20 or 30 days: One lot of the desiccated somatic embryos was encapsulated in sodium alginate gel and the other lot was not encapsulated. Both encapsulated and nonencapsulated desiccated embryos showed revival of growth upon rehydration on White’s medium and developed into plants. The desiccation tolerance and regeneration of viable plantlets depended upon the pretreatment given to somatic embryos. Embryogenic tissue subjected to dry state for 30 days showed revival of somatic embryogenesis upon transfer to a fresh nutrient medium. Implications of maturation and desiccation of somatic embryos on its germinability are discussed.     

Isolation and characterization of microsatellite loci in Santalum lanceolatum and Santalum leptocladum (Santalaceae)

? Premise of the study: Microsatellite primers were developed for the first time in the native Australian sandalwood species Santalum lanceolatum. ? Methods and Results: Using an enrichment cloning protocol, five novel polymorphic codominant loci were developed and characterized in S. lanceolatum and S. leptocladum. In addition to these, three existing microsatellite loci from other sandalwood species were successfully amplified and characterized for S. lanceolatum and S. leptocladum. Among the eight loci, allelic diversity ranged from 4 to 29. ? Conclusions: Primers will be useful for studies of clonality, genetic diversity and spatial genetic structure in wild populations. When coupled with other molecular techniques will help investigate the relationship between S. lanceolatum and S. leptocladum, species of commercial and conservation interest.     

Nutripriming of Seeds with Manganese Sulphate for Better Germination and Seedling Vigour in the East Indian Sandalwood (Santalum album L.)

Journal of Plant Growth Regulation - Poor and staggered seeds germination is the major hurdle in plantation establishment of sandalwood (Santalum album L) which is one among the esteemed timber...     

Glycolate Metabolism in Eurasian Watermilfoil (Myriophyllum spicatum)

The metabolism of glycolate by Eurasian watermilfoil (Myriophyllum spicatum L.), a submersed angiosperm, was studied by feeding radioactive glycolate and glyoxylate and by analysis of glycolate and glycolic acid oxidase. Evidence for operation of the glycolate pathway is given. Glycolic acid oxidase occurs at levels comparable to amounts in species showing photorespiration. This species has a high affinity for CO₂ and a possible mechanism for it is described.     

Biochemical characterization of Santalum album (Chandan) leaf peroxidase

The Santalum peroxidase was extracted from the leaves and precipitated with double volume of chilled acetone. The optimum percent relative activity for the Santalum peroxidase was observed at pH 5.0 and 50 °C temperature. The Santalum peroxidase per cent relative activity was stimulated in the presence of phenolic compounds like ferrulic acid and caffeic acids; however, indole-3-acetic acid (IAA) and protocatechuic acid act as inhibitors. All divalent cations Fe²⁺, Mn²⁺, Mg²⁺, Cu²⁺ and Zn²⁺ stimulate the relative activity of the Santalum peroxidase at concentration of 2.0 μM. Amino acids like L-alanine and L-valine activate the per cent relative activity, while L-proline and DL-methionine showed moderate inhibition for the Santalum peroxidase. However, a very low a concentration of cysteine acts as a strong inhibitor of Santalum peroxidase at the concentration of 0.4 mM. Native polyacrylamide gel electrophoresis (Native-PAGE) was performed for isoenzyme determination and two bands were observed. K_m and V_max values were calculated from Lineweaver-Burk graph. The apparent V_max/K_m value for O-dianisidine and H₂O₂ were 400 and 5.0 × 105 Units/min/mL respectively.     

Lectotypification of Acrostichum spicatum (Lepisorus spicatus,Polypodiaceae)

The original material of the fern species name Acrostichum spicatum (Polypodiaceae) was detected in the Linnaean Herbarium in London. It is selected as the lectotype in consultation with the protologue of the name, thus superseding the neotypes in the collections of Commerson and Sonnerat.     

Effects of eutrophication and snails on Eurasian watermilfoil (Myriophyllum spicatum) invasion

Exotic species can invade and establish new habitats both as a result of their own traits, and as a result of the characteristics of the environment they invade. Here, we show that the abundance of the invasive submerged aquatic plant, Myriophyllum spicatum (Eurasian watermilfoil) is highly dependent on the conditions of the environment in a mesocosm experiment. M. spicatum is allelopathic towards epiphytic algae, and in the absence of algivorous snails, we found that the abundance of both algae and M. spicatum significantly increased with experimentally increased nutrient loading, while the abundance of native submerged macrophytes declined. However, when snails were present, snail biomass increased with increasing nutrient loading, and M. spicatum biomass was consistently low while native submerged macrophyte biomass was consistently high. Our results stress the importance of the interaction between species traits and environmental conditions when considering the invasiveness of certain exotic species and the invasibility of certain environments.     

Mineral Elements in the Nutrition of Larger Mammals

The larger mammals, in spite of a wide diversity in diet, differcomparatively little in total mineral or ash content of thewhole body. Because of the quantity required, calcium and phosphorusare the most commonly deficient elements. Tetany caused by adeficiency of magnesium is a problem in many areas. Deficienciesin trace elements are frequently the most dramatic in termsof the problems presented and the rapid response to minute increasesin intake. The interrelationships, both direct and indirect,have caused nutritionists to realize that, in spite of manyadvances, there are many unanswered questions about the requirementsand functions of the mineral elements in the larger mammals.The bulk of research has been with domestic species, but thereis every reason to believe that wild herbivores are equallysusceptible to deficiencies in these important nutrients.     

Physiological Studies in Plant Nutrition: XVI. The Mineral Nutrition of Bracken

Part I of this paper describes culture methods for the productionof large numbers of bracken sporelings of uniform size. Observationson the growth of the bracken plant and results of experimentson the mineral nutrition of the prothallial and sporophyte generationsare presented. The presentation of further growth data and afull analysis of the results is deferred to the second partof this paper.     

Physiological Studies in Plant Nutrition: XVI. The Mineral Nutrition of Bracken

1. The nutritional requirements of the bracken sporophyte wereexamined in a factorial combination of 3 potassium levels x2phosphorus levels x3 solution types, in which the cations weremainly Na, Ca, or NH₄.
2. The effects of nitrogen and phosphorusdeficiency and of shadingunder conditions of high and low potassiumsupply were alsoexamined.
3. Leaf area, total dry weight, andnet assimilation rates aremuch depressed by lack of eitherK or P.
4. Water contents of leaves and rhizomes are generallyincreasedby lack of K when Na is present in the culture mediumbut notwhen Ca is in excess.Phosphorus causes diminished succulence.
5. Starch content increases as phosphorus supply is lowered.Withincreasing doses of K, starch content falls in the highcalciumsolution, while increasing in the other two solutiontypes.
6. Reduction of light intensity is shown to have a beneficialeffectunder conditions of K deficiency.
7. Analysis revealscomplex interactions between the various factors,and possibletoxic effect of Na, NH₄, and excess P. An estimateof the relativeimportance of net assimilation rate, leaf numberand area perleaf in determining total plant size has been calculatedforthe different nutrient treatments. Comparisons are madewithprevious results for barley and flax.