Dose responses of silvery-thread moss (Bryum argenteum) to carfentrazone-ethyl

Carfentrazone-ethyl is one of few herbicides labeled for control of silvery-thread moss (STM) in golf course putting greens, but common use rates are up to three times higher than for broadleaf weeds. Our objective was to determine the efficacy of a single postemergence application of carfentrazone-ethyl for STM control in greenhouse and field dose response studies. In the greenhouse, carfentrazone-ethyl was applied at 0, 14, 28, 56, 112, and 224 g ai ha−1 to pots containing established STM and creeping bentgrass. Percent gametophyte injury was visually estimated at 14, 28, 49, and 77 d after treatment (DAT). Shoot viability was determined by excising shoots from treated pots and plating them in petri dishes containing sand. The 28 and 49 DAT ED90 (dose required to cause 90% gametophyte injury) were 26.8 and 54.3 g ha−1, respectively; both of these doses are substantially lower than the label rates for long- and short-term control, respectively. All doses reduced the viability of transplanted shoots at 10 DAT compared to untreated STM; however, regrowth occurred in all petri dishes by 17 DAT. Field studies were initiated in Manhattan, Kansas and San Luis Obispo, California to corroborate greenhouse results. Averaged across locations, carfentrazone-ethyl applied at 56 and 112 g ha−1 caused 76% and 84% STM injury at 14 DAT, but quickly reduced to 45% and 48% STM injury by 28 DAT, respectively. In greenhouse and field studies, STM recovery did not occur until after 2 wk after treatment (WAT), which indicates the label-stipulated application interval of 2 wk is too short. Our research suggests 56 g ha−1 can provide similar burndown control of STM as compared to the highest label rate (112 g ha−1), and turfgrass managers should consider extending the reapplication interval to 3 or 4 wk when moss recovery is observed.

Indirect establishment increases the chances of in vitro propagation of mosses occurring in the Cerrado - a new method

The use of micropropagation techniques is crucial for the conservation of endangered moss species and their reestablishment in nature. This study aimed to establish in vitro cultures of gametophyte fragments of ten species of Cerrado mosses. After disinfestation with alcohol and commercial bleach, moss explants were grown in Petri dishes containing Knop medium. The species Bryum argenteum, B. coronatum, Isopterygium tenerifolium, Leucobryum crispum, Pogonatum pensilvanicum, and Vitalia cuspidifera were successively established with efficiency rate ranging from 1 to 31.2%. However, no aseptic cultures were obtained for the species Barbula indica, Bryum densifolium, Fissidens flaccidus, and Sphagnum platyphylloides. Even though, a few contaminated explants of these species were able to develop and grow. Thus, all ten species were submitted to rescue techniques to establish cultures in aseptic conditions, from partially contaminated explants (indirect establishment). Consequently, the indirect establishment resulted in higher percentages of explant development, which enhanced the establishment of in vitro cultures for most of the species tested. This fact is especially important for conservation purposes, mainly for species whose material is sensitive or scarce. Therefore, indirect establishment as a new in vitro culture methodology was a viable form of propagating the bryophyte species listed in this research. This fact is essential for conservation purpose, especially for species whose material is sensitive or scarcer.

Ecological and physiological peculiarities of bryophytes on a post-technogenic salinized territory

Taxonomic, biomorphological and ecological structures of bryophytes, their reproductive strategy and the main mechanisms of tolerance in the conditions of salinization were investigated. Bryophytes are the pioneers that have colonized the territory of a tailing storage that holds liquid waste from potassium-magnesium concentrate production of the Mining and Chemical Enterprise "Polymineral". Due to excess salts, the soil solution in the shore area of the tailing pond acquires high osmotic pressure. Three experimental plots which differed significantly in the level of the substrate salinity were laid at the distance of 3, 6 and 9 m from the reservoir for experimental studies. Water extracts of the substrates from the test sites showed the highest concentrations for sulfates – 10.4–64.6 mg Eq/100 g of soil and chlorides – 7.6–43.3 mg Eq/100 g of soil. It was established that the investigated areas of the tailing storage territory differed in the biochemical activity of the substrate, which was evaluated by its redox potential. On the areas of the uncovered substrate it was the lowest – 230 mV, which indicates anaerobiosis in conditions of very high salinization and moisture. Higher ROP values were determined at the sites of bryophyte cover distribution – 295–330 mV. The aim of the study was to determine the features of taxonomic, biomorphological and ecological structures of bryophytes, their reproductive strategy and to establish the main mechanisms of adaptation to the conditions of salinization on the tailing storage territory. 24 species and 3 varieties of bryophytes, belonging to 12 families and 16 genera were found on the shore of the tailing storage pond. The results of biomorphological and ecological analysis of bryophytes indicate the uneven conditions of the habitats and their considerable ecological plasticity. Among the bryophytes, mesophytes, xeromesophytes and meso-eutrophs, eutrophs with a life-form of low dense and loose turf dominated. In salinization conditions, dioicous acrocarpous mosses prevailed, the fertile turf of which, depending on the influence of abiotic factors, differed significantly in the number of sexual shoots, their ratio and productivity. Bulbils were found only on the tips of Bryum argenteum shoots. Along with Salicornia europaea L., a euhalophyte, the leading role in the initial stage of overgrowth of the tailing storage area most often belonged to Didymodon rigidulus, Bryum argenteum, Funaria hygrometrica and Barbula unguiculata. The process of formation of bryophyte cover occurred along a gradient of decrease in salt concentration at the experimental sites. Adaptation of bryophytes to substrate salinity is due to a change in metabolic processes, which is manifested in an increase of the total content of carbohydrates and an increase of the cation exchange capacity of moss cell walls, which is the primary barrier that reduces the toxic effect of ions under salt stress.