Joshua D. Klein

Willow (Salix spp.) trees, found worldwide, contain secondary metabolites that are valuable as dietary supplements for animal feed and as antiparasitic compounds. We quantified secondary metabolites (phenolics, flavonoids, and salicylic acid) in ethanolic extracts from leaves and branches of three Salix acmophylla Boiss. genotypes and investigated their potential to inhibit Eimeria sp. sporulation, a major concern in ruminants. The total phenolic content of willow leaves and branches was similar in two of three different genotypes. The total flavonoid content of the branches was significantly higher than that of leaves of the same genotype; however, the salicylic acid content was significantly higher in leaves than in branches. Importantly, all extracts exhibited significant inhibition of Eimeria sporulation, where over 70% inhibition was obtained at concentrations as low as 750 mgL⁻¹. The sporulation inhibition by branch or leaf extracts exceeded 80% for leaves and 90% for branches at concentrations above 1250 mgL⁻¹. The study highlights the potential of using Salix extracts as bioactive compounds for biological control of coccidiosis in ruminants. We conclude that all parts and all investigated genotypes of S. acmophylla can provide secondary metabolites that act as a coccidiostat to treat Eimeria in goats.

Willow (Salix spp.) trees, found worldwide, contain secondary metabolites that are valuable as dietary supplements for animal feed and as anti-parasitic compounds. We quantified secondary metabolites (phenolic, flavonoids, and salicylic acid) in ethanolic extracts from leaves and branches of three Salix acmophylla genotypes and investigated their potential to inhibit Eimeria sp. sporulation, a major concern in ruminants. The total phenolic content of willow leaves and branches was similar in two of three different genotypes. The total flavonoid content of the branches was significantly higher than that of leaves of the same genotype; however, the salicylic acid content was significantly higher in leaves than in branches. Importantly, all extracts exhibited significant inhibition of Eimeria sporulation, where over 70% inhibition was obtained at concentrations as low as 750 ppm. The sporulation inhibition by branch or leaf extracts exceeded 80% for leaves and 90% for branches at concentrations above 1250 ppm. The study highlights the potential of using Salix extracts as bioactive compounds for biological control of coccidiosis in ruminants and emphasizes the importance of genotype-specific variations in secondary metabolite profiles. We conclude that all parts of S. acmophylla can provide secondary metabolites that act as a coccidiostat to treat Eimeria in goats.

Combinations of Dilwet, an organosilicone surfactant, and ethephon, a hormonal compound often applied to fruit trees to thin the crop, were applied at full bloom to prevent fruit development in two young vineyards differing in elevation by 600 m. Each vineyard was planted with the same 19 red and 10 white grape cultivars from a range of countries of origin. Vineyard elevation did not affect response to treatment. A combined spray of 0.5% Dilwet with 0.04% ethephon reduced cluster number by an average of 85%, while weight of the remaining clusters was reduced by 63%, compared to unsprayed controls. Increasing the concentration of Dilwet to 1% reduced cluster number by 93% and cluster weight by 76%. There were significant differences in the response of cultivars to the treatments, depending on country of origin, with grapes originating in France responding better to higher concentrations of Dilwet. White grapes were more responsive than red grapes. These results highlight the need to test different cultivars and genetic origins of crops when examining the effects of new agricultural chemicals.

Salix acmophylla Boiss. has a traditional role in several regions of the Middle East and the Indian subcontinent. As with many other woody species, the development of methods for fast propagation and ex situ conservation of this species is needed. We describe for the first time a micropropagation protocol of three S. acmophylla ecotypes. The best results for shoot proliferation were obtained by culturing the shoot explants on Woody Plant Medium (WPM) containing benzyladenine (BA) 5 μM, but it was also observed that proliferation can be further enhanced by the separation of the shoot tip from the underlying internodes, followed by their respective culture on BA- or activated-charcoal-containing medium. Thidiazuron or zeatin did not enhance shoot proliferation. The rooting of shoots occurred spontaneously, but for the ecotype with a lower propensity for rooting, treatment with 5 μM indolebutyric acid (IBA) increased rooting percentage. Genetic differences were evident in rooting success, but not in shoot development of the tested ecotypes in response to in vitro cultural conditions.

Few phytoremediation studies have been conducted under semi-arid conditions where plants are subjected to drought and/or salinity stress. Although the genus Salix is frequently used in phytoremediation, information regarding its tolerance of drought and salinity is limited. In the present study, Salix acmophylla Boiss. cuttings from three sites (Adom, Darom and Mea She’arim) were tested for tolerance to salinity stress by growing them hydroponically under either control or increasing NaCl concentrations corresponding to electrical conductivities of 3 and 6 dS m⁻¹ in a 42-day greenhouse trial. Gas exchange parameters, chlorophyll fluorescence and concentration, and water-use efficiency were measured weekly and biomass was collected at the end of the trial. Root, leaf and stem productivity was significantly reduced in the Adom ecotype, suggesting that Darom and Mea She’arim are the more salt-tolerant of the three ecotypes. Net assimilation and stomatal conductance rates in salt-treated Adom were significantly reduced by the last week of the trial, coinciding with reduced intrinsic water use efficiency and chlorophyll a content and greater stomatal aperture. In contrast, early reductions in stomatal conductance and stomatal aperture in Darom and Mea She’arim stabilized, together with pigment concentrations, especially carotenoids. These results suggest that Darom and Mea She’arim are more tolerant to salt than Adom, and provide further phenotypic support to the recently published data demonstrating their genetic similarities and their usefulness in phytoremediation under saline conditions.

Juvenile and vegetative adult shoot apical meristems (SAM) are actively involved in acquisition of flowering competence, while the embryonic SAM is regarded as “responsible” only for germination. Comparative analyses of imbibed and stratified seeds of garlic Allium sativum show that only stratified seedlings produced bulbs and flower stems at the end of the season. Since the seed morphology of stratified and non-stratified seeds prior to sowing was similar, the differences are attributed to the molecular alterations in the embryonic SAM. Functional annotation analysis of 3000 differentially expressed genes suggests that seed imbibition reactivates the embryonic cell cycle, initiates the metabolism, and primes garlic seed germination. Stratification enhances DNA modifications, biosynthesis, cellular transport, and tissue development. Similar to vernalization of the vegetative buds, stratification of the embryonic SAM resulted in altered expression of meristem-identity and flowering homologs. Phase transitions from seed germination to flowering and bulbing in A. sativum are tightly connected, and possibly associated with downregulation of specific flowering repressor(s). The embryonic SAM plays an important role not only in seed germination, but in the entire plant life cycle, providing the foundation for the genetic regulation of major functional shifts in metabolism and development.

Our “diabetogenic diet” composition [1] was indeed based on the one described by Funda et al. [2] with regards to dietary requirements.