Clonal Propagation of Valeriana jatamansi Retains the Essential Oil Profile of Mother Plants: An Approach Toward Generating Homogenous Grade of Essential Oil for Industrial Use

Valeriana jatamansi Jones (Syn. V. wallichii DC.) is an aromatic, medicinal herb used as a tranquilizer and in treating sleep disorders. Rhizome is mainly used to extract essential oil (EO) and valepotriates. High quality and economic yield of rhizomes are available in the third year of growth. Therefore, the cultivation of V. jatamansi is not picking up, and over-exploitation of this plant from wild habitats to meet the increasing demand of the pharmaceutical industry is the cause of threat to the genetic diversity of the species. Further, collections from the wild are heterogeneous, resulting in variable produce. The development of clonal lines can ensure uniform quality and yield of rhizome biomass. An effective clonal propagation method was standardized using different hormonal concentrations of naphthalene acetic acid (NAA) on apical shoot cuttings from the selected clone CSIR-IHBT-VJ-05 for different time durations and raised over various planting media. NAA treatment of 50 ppm concentration for 30 min was found optimum for root induction in apical shoots of V. jatamansi. Variations for EO composition within the clone were non-significant, while samples of the control population were variable. The best quality EO (patchouli alcohol ∼62%) was available during the third year of plant growth. A propagation technique for large-scale quality plant material (QPM) production has been standardized to reduce the stress over natural resources and promote V. jatamansi for use in the aromatic and pharmaceutical industry.

Trait gradients inform predictions of seagrass meadows changes to future warming

Comparing populations across temperature gradients can inform how global warming will impact the structure and function of ecosystems. Shoot density, morphometry and productivity of the seagrass Posidonia oceanica to temperature variation was quantified at eight locations in Sardinia (western Mediterranean Sea) along a natural sea surface temperature (SST) gradient. The locations are spanned for a narrow range of latitude (1.5°), allowing the minimization of the effect of eventual photoperiod variability. Mean SST predicted P. oceanica meadow structure, with increased temperature correlated with higher shoot density, but lower leaf and rhizome width, and rhizome biomass. Chlorophyll a (Chl-a) strongly impacted seagrass traits independent of SST. Disentangling the effects of SST and Chl-a on seagrass meadow shoot density revealed that they work independently, but in the same direction with potential synergism. Space-for-time substitution predicts that global warming will trigger denser seagrass meadows with slender shoots, fewer leaves, and strongly impact seagrass ecosystem. Future investigations should evaluate if global warming will erode the ecosystem services provided by seagrass meadows.

Ramet specialization allows similar performance of the invasive macrophyte Hedychium coronarium under different light and intraspecific competition levels

Invasive species can affect ecosystems functioning by forming dense monospecific stands and outcompeting native plants. However, the performance of the invader depends on its plastic responses to abiotic attributes of invaded communities. Understanding the interplay between intraspecific competition and environmental conditions is important to elucidate the domain and aggressive potential of invasive species. Here, we assessed the performance of the invasive Hedychium coronarium in two levels of intraspecific competition created through rhizome density under full light and partial shade. We tested the influence of light, density and their interaction on ramet length and number of ramets during the first three months after planting (phase 1) and after 22 months (phase 2), and on rhizome dry weight and the ramet/rhizome biomass ratio in phase 2. In both phases, ramets were longer under shade and the number of ramets was higher under low rhizome density indicating lower intraspecific competition. In phase 2, there was a negative effect of rhizome density on ramet length, but it was restricted to shade, probably due to the aggravation of competition for light. Rhizome dry weight was greater under shade conditions and it was not affected by rhizome density, and ramet/rhizome ratio did not differ between treatments. Our results supported a large phenotypic plasticity of H. coronarium ramets, which allowed similar performances despite variations in environmental conditions and population densities. We suggest that this mechanism of energy allocation enhances the success of this invasive plant in varied habitats, such as open and closed, forested sites.

Trait Gradients Predict Global Warming Changes in Seagrass Meadows

Comparing populations across temperature gradients can inform how global warming will impact the structure and function of ecosystems. Shoot density, morphometry and productivity of the seagrass Posidonia oceanica to temperature variation was quantified at eight locations in Sardinia (western Mediterranean Sea) along a natural sea surface temperature (SST) gradient. The locations are spanned for a narrow range of latitude (1.5°), allowing the minimization of the effect of eventual photoperiod variability. Mean SST predicted P. oceanica meadow structure, with increased temperature correlated with higher shoot density, but lower leaf and rhizome width, and rhizome biomass. Chlorophyll a (Chl-a) strongly impacted seagrass traits independent of SST. Disentangling the effects of SST and Chl-a on seagrass meadow density revealed that they work independently, but in the same direction with potential synergism.Space-for-time substitution predicts that global warming will trigger denser seagrass meadows with slender shoots, fewer leaves, and strongly impact seagrass ecosystem. Future investigations should evaluate if global warming will erode the ecosystem services provided by seagrass meadows.

Invasive plant rhizome production and competitiveness vary based on neighbor identity

Aims Within-species genetic and phenotypic variations have well-known effects on evolutionary processes, but less is known about how within species variation may influence community-level processes. Ecologically meaningful intraspecific variation might be particularly important in the context of anthropogenic impacts on natural systems, such as agriculture and species invasion, because human actions can cause strong selection pressures. Methods In a greenhouse study, we explored intraspecific (30 accessions) and ecotypic variation (representing agricultural and non-agricultural habitats) in biomass and rhizome production in response to inter- and intra-specific competition and soil fertility of Johnsongrass (Sorghum halepense), a widespread invasive species and agricultural weed. Important findings Contrary to our expectations and previous results, we did not find variation in biomass production among Johnsongrass ecotypes at this early life stage. However, we did find that Johnsongrass biomass varied substantially depending on competitor identity, soil fertility treatments, and among accessions. Rhizomes were 11% larger in the agricultural ecotype and up to 3-fold larger in fertilized treatment; while rhizome biomass increased by ~50% when fertilized, but did not differ among ecotypes. Interestingly, in competition, Johnsongrass produced 32% less biomass and 20% less rhizome mass with a conspecific than when competing interspecifically with corn. Our results indicate species-specific competitive responses and changes in rhizome allocation in response to neighbor identity; suggesting the possibility of adaptation by Johnsongrass to shift allocation under competition.

Differential Germination and Growth Response to Temperature of Three Ambrosia Weed Species—Implications for Future Spread

Three main Ambrosia species (Ragweed) grow in Israel; the most abundant invasive Ambrosia confertiflora DC, whereas A. artemisiifolia L. and A. tenuifolia Spreng., are of restricted distribution. The present research was aimed to study the effect of temperatures regimes on the development and growth of these Ambrosia species, to elucidate the environmental conditions and plant traits that affect their growth and infestation patterns. All three Ambrosia species germinate best in light from the soil surface with no prerequisite of a stratification period. A. confertiflora seed emergence is inhibited at high temperature regimes (28/34°C). A. artemisiifolia at low temperature regimes (10/16°C), while A. tenuifolia is less affected by the temperature regimes. A. confertiflora plant height increases with increasing temperatures, and at lower temperatures develops a rosette. Root and rhizome biomass were less affected by the different temperatures regimes; A. artemisiifolia aboveground mass was not affected by temperature regimes while A. tenuifolia aboveground mass was reduced only at lower temperatures. A. confertiflora fast invasion and establishment are due to the combined effects of prolific seed dispersal, rapid sprouting and growth, and its phenotypic plasticity.

Long-Term Control of Hedge Bindweed (Calystegia sepium L.) with Single, Tank Mixture, and Sequential Applications of Glyphosate, 2,4-D, and Dicamba

Hedge bindweed (Calystegia sepium L.) is a widespread troublesome perennial weed species that has strong rhizome regenerative capacity. Four pot trials with randomised, complete block designs were conducted in 2015 to evaluate long-term control of hedge bindweed using individual, tank mixture, and sequential applications of selected herbicides. Two different formulations of N-(phosphonomethyl) glycine (glyphosate; isopropylamine, trimesium salts) were applied at 2000 g active ingredient (a.i.) ha−1. Additionally, two synthetic auxins were applied as 3,6-dichloro-2-methoxybenzoic acid (dicamba) at 500 g a.i. ha−1 and the dimethylamine salt of (2,4 dichlorophenoxy)acetic acid (2,4-D) at 1000 g a.i. ha−1. Tank mixtures and sequential applications (12/24 h separation) of these different herbicides were also included. Long-term control of hedge bindweed, Calystegia sepium L., growth was evaluated 8 months after treatments, as comparisons of shoot and rhizome growth (biomass) between untreated and treated plants. There were no differences between the two formulations of glyphosate alone, with shoot and rhizome biomass reductions of 83% and 42%, respectively. Dicamba alone inhibited shoot and rhizome biomass by 86% and 67%, respectively. By itself, 2,4-D provided the greatest reductions in shoot and rhizome biomasses, 93% and 79%, respectively. Antagonism was seen in the tank mixtures of glyphosate and dicamba or 2,4-D. Tank mixtures were generally comparable to treatments of glyphosate alone, and were less effective compared to dicamba or 2,4-D alone. The greatest reduction of bindweed rhizome biomass was for sequential glyphosate trimesium salt followed by 2,4-D 12 h later, thus showing significantly greater efficacy over glyphosate isopropylamine salt (94% vs. 84%; p ≤ 0.05). These data for reductions of the growth of the rhizome biomass show that the sequential application of glyphosate followed by 2,4-D significantly improves long-term control of hedge bindweed.

Role of nitrogen and herbicides in integrated management of mugwort (Artemisia vulgaris) in cool-season forage grasses

Mugwort (Artemisia vulgaris L.) is becoming increasingly problematic in cool-season pastures and grasslands. A 3-yr field experiment evaluated different rates of nitrogen and herbicides for A. vulgaris management in a permanent grassland. The main plot had three nitrogen rates, 0, 62, and 124 kg N ha−1; the subplot had three herbicides, aminopyralid, clopyralid, and glyphosate; and the sub-subplot had three herbicide rates, aminopyralid (61, 122, and 244 g ae ha−1), clopyralid (140, 280, and 560 g ae ha−1), and glyphosate (552, 1,104, and 2,208 g ae ha−1). Results revealed that nitrogen had no effect on A. vulgaris control, rhizome biomass, and stem density. However, cool-season grass biomass was the highest (7,126 kg ha−1) in the plots that received 124 kg N ha−1 and 244 g ae ha−1 of aminopyralid. Only glyphosate caused grass injury, which varied from 65% to 100% depending upon application rate. By 9 mo after initial herbicide treatment (MAIT), A. vulgaris was controlled 60% to 98% with aminopyralid at ≥61 g ae ha−1 or glyphosate at ≥552 g ae ha−1. By 21 MAIT, aminopyralid at ≥122 g ae ha−1 or glyphosate at ≥1,104 g ae ha−1 resulted in >95% reduction in A. vulgaris stem density and rhizome biomass and provided ≥98% visual control. By 33 MAIT, complete control of A. vulgaris was confirmed in plots treated with aminopyralid at ≥122 g ae ha−1 or glyphosate at ≥1,104 g ae ha−1. Clopyralid was not effective; A. vulgaris control was <40% even after three annual applications at 560 g ae ha−1. Results indicate that integration of nitrogen fertilization with aminopyralid did not improve A. vulgaris control, but was advantageous in enhancing cool-season grass productivity.

The Influence of Processing and Particle Size on Binderless Particleboards Made from Arundo donax L. Rhizome

The giant reed (Arundo donax L.) is considered one of the world’s 100 worst invasive species. The main method by which this species propagates is by growth of scattered fragments of rhizome, spreading without control with very strong, deep roots. Agricultural waste consists of lignocellulosic materials that can substitute natural wood and offer a suitable alternative with which to manufacture boards for furniture, packaging and building purposes. The objectives of this work were to obtain binderless particleboards using giant reed rhizome as the raw material, to evaluate their mechanical and physical properties according to the applicable European standards and to assess the self-binding mechanism of the particles in the board. Six types of boards (12 classes) were manufactured with giant reed rhizome biomass. They were manufactured with a temperature of 110 °C, a pressure of 2.5 MPa and pressing times of 7 and 15 min, applying one or two pressing cycles. The results achieved for modulus of rupture (14.2 N/mm2), modulus of elasticity (2052.45 N/mm2) and internal bonding strength (1.12 N/mm2) show that the mechanical properties were improved by using a smaller rhizome particle size and two pressing cycles.