Substitution of fresh forage ramie for alfalfa hay in diets affects production performance, milk composition, and serum parameters of dairy cows.[Pubmed: 30112731]

We hypothesized that ramie, Boehmeria nivea (a nettle native to Asia), can be used as a high-quality forage to replace alfalfa hay in diets of dairy cows. Accordingly, we aimed to examine the effects of substituting fresh forage ramie for alfalfa (Medicago sativa) hay on production performance, milk composition, and serum parameters of dairy cows. Thirty-two Holstein cows (body weight (BW) = 590 ± 50.6 kg) were randomly divided into four groups of eight cows. The experimental period lasted 10 weeks. The dietary treatments consisted of four proportions of fresh forage ramie (0, 33, 67, and 100%) as a substitute for alfalfa hay (designated as CON, FR33, FR67, and FR100, respectively). On days 69 and 70 of the experimental period, milk and blood samples were collected for analysis. We found no significant differences in the milk yield and milk quality (milk protein percentage, milk fat percentage, and milk lactose percentage) between the treatments. We did find that forage ramie significantly reduced dry matter intake (DMI) and 4% fat-corrected milk (FCM) yield. Meanwhile, no significant differences were detected in serum parameters between the treatments, with the exception of triglyceride (TG) and alanine aminotransferase (ALT). In conclusion, our data indicate that alfalfa hay can be replaced with forage ramie in the diet of Holstein cows in the milk lactation stage, with no negative effects on milk quality and blood parameters.

Comparison of intracellular location and stimulus reaction times of forisomes in sieve tubes of four legume species.[Pubmed: 30111246]

Forisomes in legumes are responsible for fast sieve-element occlusion in response to injury to the vascular system. This prevents uncontrolled leakage of phloem sap and protects against invasion of pathogens. Here we compared forisomes of four different legumes (Pisum sativum, Vicia faba, Trifolium pratense and Medicago sativa) by their location (basal, central, apical) in the sieve element and reactivity to a distant heat stimulus. In each species, the majority of forisomes was located basally. Yet, we found differences in intracellular location: forisomes are distributed more evenly in the sieve elements of Pisum. After burning, basally located forisomes of the four species reacted with dispersion, followed by a spontaneous recondensation with similar reaction times. The results suggest universal forisome behaviour in fabacean species.

Dynamics of Predation on Lygus hesperus (Hemiptera: Miridae) in Alfalfa Trap-Cropped Organic Strawberry.[Pubmed: 30101306]

Alfalfa (Medicago sativa L.) (Fabales: Fabaceae) can be strategically planted as a trap crop for Lygus spp. in California's organic strawberry fields. Alfalfa has been shown to attract both Lygus spp. and, in turn, a Lygus-specific parasitoid, Peristenus relictus (Ruthe) (Hymenoptera: Braconidae). However, the impact of alfalfa trap-cropped strawberries on the Lygus spp. predator complex is unknown. Here we identify key predators of Lygus spp. found in organic strawberry. First, a general survey was conducted at an organic, non-trap cropped strawberry farm, to quantify predator abundance and to qualitatively assess their feeding activity on Lygus spp. We identified the 11 most abundant predator taxa present and, by using a Lygus-specific PCR assay, determined that about 18% of the insects and spiders contained Lygus spp. remains in their guts. We then conducted a study to examine alfalfa's role in conserving the most relevant predators in trap-cropped organic strawberries. Specifically, we quantified predator abundance and qualitatively measured predator feeding activity (by gut analysis) on Lygus spp. collected in strawberry plots either lacking or containing an alfalfa trap crop. Data revealed that some predator taxa, including the numerically dominant predator, Orius tristicolor (White) (Hemiptera: Anthocoridae), aggregated in alfalfa trap crops. The gut content analyses revealed that insect and spider predators collected from the alfalfa trap crop had a significantly higher proportion of their population containing Lygus spp. remains than those collected from nearby rows of strawberries. These results suggest that alfalfa trap cropping might be a useful tactic for conserving the biological control services of generalist predators in organically grown strawberries in California.

Remediation of soil polluted with HMW-PAHs by alfalfa or brome in combination with fungi and starch.[Pubmed: 30098530]

High-molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) are common pollutants in soil of coal mining areas that affect the safety of crops and the environment. In a pot experiment, we compared the remediation potential of alfalfa (Medicago sativa Linn) and brome (Bromus inermis Leyss.) either alone or in combination with starch or Fusarium sp. strain ZH-H2 for a farmland soil contaminated with 4-6-ring PAHs from a coal mine area. The alfalfa and brome alone treatments reduced the concentrations of most HMW-PAHs. However, when starch was added, the removal rates of indeno(1,2,3-cd)pyrene and benzo(ghi)perylene were significantly higher for brome than for alfalfa. When ZH-H2 was combined with brome, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, and benzo(ghi)perylene degradation rates were significantly enhanced compared with brome alone. In contrast, an antagonistic effect was observed between alfalfa and Fusarium. The brome, starch and ZH-H2 combination resulted in far better removal rates than the alfalfa combination. Maximum removal rates were obtained with the brome + starch + ZH-H2 combination for benzo(k)fluoranthene (42.64%), benzo(a)pyrene (51.01%), indeno(1,2,3-cd)pyrene (62.29%), and benzo(ghi)perylene (74.85%). These removal rates were 829.78%, 182.34%, 46.13%, and 70.94% higher than the equivalent alfalfa combination treatments. The lignin peroxidase activity was significantly increased in the presence of starch, ZH-H2 and brome, consistent with the increased removal rates of HMW-PAHs.

Nontargeted metabolomic analysis to unravel the impact of di (2-ethylhexyl) phthalate stress on root exudates of alfalfa (Medicago sativa).[Pubmed: 30053665]

Root exudates are the main media of information communication and energy transfer between plant roots and the soil. Understanding the response of root exudates to contamination stress is crucial in revealing the rhizoremediation mechanisms. Here, we investigate the response of alfalfa root exudates to bis(2-ethylhexyl) phthalate (DEHP) stress based on nontargeted metabolomic analysis. Alfalfa root exudates were collected using greenhouse hydroponic culture and analysed by gas chromatography-time of flight mass spectrometry (GC-TOFMS). A total of 314 compounds were identified in alfalfa root exudates of which carbohydrates, acids and lipids accounted for 28.6, 15.58 and 13.87%, respectively. Orthogonal partial least squares discriminant analysis (OPLS-DA) shows that DEHP exerted an important influence on the composition and quantity of root exudates. Fifty metabolites were clearly changed even at lower concentrations of DEHP, including common carbohydrates, fatty acids and some special rhizosphere signal materials, such as 4',5-dihyrroxy-7-methoxyisoflavone. DEHP stress significantly suppressed carbohydrate metabolism but promoted fatty acid metabolism. However, amino acid metabolism, lipid metabolism and the tricarboxylic acid (TCA) cycle showed little change in response to DEHP stress.

(E)-β-farnesene synthase gene affects aphid behavior in transgenic Medicago sativa.[Pubmed: 30051587]

Pea aphid (Acyrthosiphon pisum Harris) is one of the major pests in alfalfa crops, causing significant yield losses. (E)-β-farnesene (EβF), an alarm pheromone released by pea aphid, is generic to many species of aphids, and used to minimise potential danger from predators and parasitoids by avoiding the source of the pheromone.