Leaf physiological and water soluble carbohydrate content responses to trinexapac-ethyl application of sports turf grasses exposed to water stress

Water stress causes alterations in physiological and metabolic processes in plants and is considered the primary environmental factor affecting the management of sports turf grass species.This glasshouse experiment was conducted to investigate the effect of trinexapac-ethyl (TE) on canopy net photosynthesis (Pn), cell membrane stability (CMS), turf quality (TQ) and water soluble carbohydrate (WSC) accumulation responses of sports turf cultivars [Cv] (100% fescue, Rootzone and Arena sports) subjected to water stress. Commercially obtained sods of turf plants were treated with 2 L/ ha TE and then exposed 7 days after to water stress. The treatments were: (i) water untreated, (ii) water TE-treated, (iii) water stress untreated; and (iv) water stress TE-treated and the experiment was a randomized complete block design with four replicates. Results showed that specifically in Cv. Rootzone, Pn was 50% higher for well water TE treated plants compared to the other treatments during the second and third week of the study. Similarly, at 14 days after application, the effect TE resulted to 35% and 50% reduction in cell membrane leakages respectively in well water and water stressed TE-treated Cv. Rootzone plants and this was statistically significant (P=0.05) different from the untreated plants. On a scale of 1-9, all turf types recorded TQ rating of ≥8 at the start of the experiment. By the fourth week of the study, it was observed that all water stress untreated plants had mean TQ (5.75) ratings lower than the minimum acceptable TQ (6). WSC content of well-watered TE-untreated plants was maintained below 60 mg/g DW throughout the study regardless of turf type. After 28 day of water stress duration, the WSC contents obtained in water stress TE-treated plants were 41%, 43% and 50% higher for Cv. Rootzone, 100% fescue and Cv. Arena sports, respectively , than in well water untreated plants. Summer preconditioning of plants with TE can be a possible management tool in alleviating the detrimental impacts of water stress in sport turf species

Effectiveness of defatted seed meals from Brassicaceae with or without crude glycerin against black grass ( Alopecurus myosuroides Huds.)

Herbicide resistance has become an increasing problem, and at the same time pesticide usage is declining due to stringent EU pesticide legislation which aims to reduce the impact on environment and human health. For these reasons, new alternative integrated weed management approaches are becoming increasingly relevant. Formulations based on Brassica defatted seed meals (DSMs) and glycerin, have previously been shown to be effective in reducing the germination of lettuce seed. In this work five DSMs, formulated with and without crude glycerin, were chosen for in vitro and glasshouse experiments: i) Brassica nigra, ii) Brassica tournefortii, iii) Eruca sativa, iv) Rapistrum rugosum and v) Sinapis alba. Black-grass (Alopecurus myosuroides), a weed demonstrating extensive herbicide resistance, was used as a target, and the germination inhibition caused on this weed by Brassica defatted seed meals was assessed. In both in vitro and in vivo experiments, the most effective DSM for inhibiting germination of both lettuce and black-grass seeds was the sinigrin containing DSM, Brassica nigra. The aim of the manuscript was to suggest a new high value application for Brassicas derived DSM as a co-products from the vegetable oil production chain. The proposed treatments could represent an interesting and 100% novel natural alternative to the conventional herbicides

Effects of concentrations of Brassica napus (L.) water extracts on the germination and growth of weed species

Rapeseed (Brassica napus L.) contains allelochemicals that reduces the germination and growth of weed species. An in-vitro experiment was carried out to investigate the effects of different concentrationsof B. napus(L.) water extracts from leaves, stems, roots and flowers on the seed germination and seedling growth of Phalaris minor (Retz.), Convolvulus arvensis (L.) and Sorghum halepense (L.) weeds. All treatments significantly inhibited seed germination, root length, fresh root weight, shoot length and fresh shoot weight of all weed species over the control. The inhibitory effects were concentration dependent. Flower and stem water extracts were most inhibitory to seed germination and root length of all weed species. This work highlighted the allelopathic potential of B. napus extracts for the management of weeds

Moderate water stress prevents the postharvest decline of ascorbic acid in spinach (Spinacia oleraceaL.) but not in spinach beet (Beta vulgaris L.)

BACKGROUND: Babyleaf salads such as spinach (Spinacia oleracea L.) and spinach beet (Beta vulgaris L. subsp. cicla var. cicla) are an important dietary source of antioxidants such as ascorbic acid (vitamin C). Such compounds may be important in disease prevention in consumers but the level of these compounds in leaves frequently declines after harvest. As such, methods to maintain antioxidant levels in fresh produce are being sought. RESULTS: Irrigation deficits were used to apply water stress to S. oleracea and B. vulgaris plants. This treatment prevented postharvest decline of leaf ascorbic acid content in S. oleracea but not in B. vulgaris. Ascorbic acid levels in leaves at harvest were unaffected by the treatment in both species compared to well-watered controls. CONCLUSION: We have shown that restricted irrigation provides a viable means to maintain leaf vitamin content after harvest in S. oleracea, an important finding for producers, retailers and consumers alike. © 2015 Society of Chemical Industry

Artificial alkalizing drought signals as potential growth retardants.

Excessive growth is detrimental in crops by increasing lodging and disease, and reducing light penetration into the canopy. These effects lead to management problems and reduce yield and quality of produce. Synthetic growth retardants can be used to reduce these problems. In some crops, however, it is not common practice to apply growth retardants because either: there are no approved active substances; the retardants available are expensive; or application of synthetic active substances may not be permitted in the retailer produce specifications. There is thus scope for lower-cost growth retardants that are acceptable to retailers. Basic research into the control of leaf growth has shown that, in some species, retardation of leaf growth during drought may result from an alkalizing signal moving from the roots to the leaves. Experiments with detached shoots of canola (oilseed rape; Brassica napus L.) and barley (Hordeum vulgare L.) have shown that both species respond to artificial alkaline xylem sap with reduced leaf expansion. Spray applications of alkaline pH buffers to intact plants of canola have, however, been variable in effects on leaf expansion. This may be a result of either, difficulty in penetrating the thick layer of epicuticular wax on canola, or efficient internal buffering. Application of either alkaline pH buffers, or of solid calcium carbonate (lime), to field-grown barley has, however, retarded canopy expansion for a short period. These results, together with those from recent experiments on cilantro (coriander; Coriandrum sativum L.), indicate that the greatest commercial potential for alkalizing growth retardants may be with short duration crops, and possibly with crops that also do not have a thick layer of epicuticular wax

A basis for controlling herb growth.

Excessive growth in crops leads to management problems and reduces yield and quality of produce. Synthetic growth retardants can be used to reduce these problems. In some crops, however, it is not common practice to apply growth retardants because either: there are no approved active substances; the retardants available are expensive; or application of synthetic active substances may not be permitted in the retailer produce specifications. There is thus scope for lower-cost growth retardants that are acceptable to retailers. Basic research into the control of leaf growth has shown acid pH in the cell walls is necessary for cell expansion, and in some species, retardation of leaf growth during drought may result from alkaline sap moving from the roots to the leaves, neutralising the normal acidity. Exploiting this knowledge may enable a cheaper growth retardant to be used based on food ingredients or on commodity substances already approved for other uses. Research at Harper Adams has focused on arable crops. Experiments with detached shoots of oilseed rape and barley have shown that both species respond to artificial alkaline xylem sap with reduced leaf expansion. Spray applications of alkaline pH buffers to intact plants of oilseed rape have, however, been variable in effects on leaf expansion. This was thought to possibly be a result of difficulty in penetrating the thick layer of epicuticular wax. Application of either alkaline pH buffers, or of solid calcium carbonate (lime), to field-grown barley has retarded leaf canopy expansion, but only for a short period. Thus the greatest commercial potential for alkalizing growth retardants may be with short duration crops, and possibly with crops that also do not have a thick layer of epicuticular wax. Herbs may present the best opportunity, and recent experiments indicate that coriander is sensitive to reduced growth from alkaline bicarbonate applications. HDC Project PE 005 aims to discover whether this effect is commercially useful on coriander, basil, mint and flat leaf parsley

Expression of glutathione-S-transferase and its role in plant growth and development in vivo and shoot morphogenesis in vitro

10.1007/s11103-004-4516-1Plant Molecular Biology57153-66PMBI