Evaluation of a Commercial Extract of Giant Knotweed on Drought Tolerance of Impatiens

Regalia®, a commercial extract of giant knotweed [Fallopia sachalinensis F. Schmidt (synonyms: Reynoutria sachalinensis (F. Schmidt) Nakai, Polygonum sachalinense F. Schmidt, Tiniaria sachalinesis (F. Schmidt) Janch.)], was evaluated for its potential to enhance drought tolerance of container-grown impatiens (Impatiens walleriana Hook. f. ‘Super Elfin XP White’). In two separate experiments, Regalia® was foliar-applied once a week for 4 weeks at four different rates (0, 5, 10, or 15 mL·L−1). In Expt. 1, Regalia® was applied to impatiens grown under three target substrate volumetric water contents (TVWCs): 85%, 55%, or 25%. In Expt. 2, Regalia® was applied to impatiens watered with 1, 3, or 6 days between waterings (DBW). In Expt. 1, root dry weight (RDW) of impatiens receiving applications of Regalia® at the 0.5× rate was greater compared with the 0.0× rate across all TVWCs. Additionally, soluble protein content was greater after Regalia® application at the 0.5×, 1.0×, or 1.5× rates compared with the 0.0× rate for plants grown at 55% TVWC. In Expt. 2, leaf greenness (SPAD) and leaf net photosynthetic rate (Pn) were greater with Regalia® applied at the 0.5× and 1.0× rates compared with the 0.0× rate, respectively. Soluble protein content was greater in impatiens treated with Regalia® at the 1.5× rate and 1 DBW and the 0.5× rate with 3 DBW compared with the 0.0× rate with 1 or 3 DBW. However, there was no indication that impatiens grown under different moisture levels had increased drought tolerance after application of Regalia®.

Biological Characteristics and Fodder Value of Some Species of Plants of the Genus Polygonum L. Under the Conditions of the Republic of Moldova

Giant knotweed Polygonum sachalinense, weyrich's knotweed Polygonum weyrichii and spread wide knotweed P. divaricatum species from the collection of nontraditional fodder plants, Botanical Garden (Institute) of Academy of Sciences of Moldova, as objects of study have been served. The annual productivity of P. sachalinense was 12.42 kg/m2 of fresh mass or 3.09 kg/m2 of absolutely dry matter, P. weyrichii - 7.70 kg/m2 or 2.15 kg/m2 and P. divaricatum - 5.35 kg/m2 and 1.45 kg/m2 respectively. The species P. sachalinense is characterized by a protein (16.48%) and fat content (2.53%) at the level of fodder legumes. The content of these substances is lower in the species P. weyrichii and P. divaricatum compared with P. sachalinense but higher than in traditional forage crops: corn, sudan grass and sunflower. The nutritive value of natural fodder of species of the genus Polygonum is characterized by 0.20 to 0.23 nutritive units with a metabolizable energy content for cattle of 2.43 - 2.87 MJ / kg. The species P. sachalinense has a higher nutritional value of the natural fodder and is used in the production of quality silage.

Antimicrobial Substances from Rhizomes of the Giant Knotweed Polygonum sachalinense against the Fish Pathogen Photobacterium damselae subsp. piscicida

The antimicrobial compounds against the fish pathogen Photobacterium damselae subsp. piscicida were isolated from Polygonum sachalinense rhizomes. The structures of the antimicrobial compounds 1 and 2 were determined by 1H and 13C NMR, 2D-NMR (COSY, HSQC, HMBC and ROESY) and FAB-MS to be phenylpropanoid glycosides, vanicoside A and B, respectively. Both compounds have feruloyl and p-coumaroyl groups bonded to a sucrose moiety in their structures. Vanicoside A also has an acetyl group in the sucrose moiety. The MIC values for vanicoside A and B against Ph. damselae subsp. piscicida DPp-1 were 32 and 64 μg/ml, respectively. The antimicrobial activities of these vanicosides were modest, in contrast to higher activities (MICs at <4 μg/ml) of antibiotics, florphenicol, ampicillin and amoxicillin, which have been generally used for treating pasteurellosis. The activities of the vanicosides, however, were higher than those (MICs at 256 μg/ml) of ferulic acid and p-coumaric acid. It was suggested that the structure of phenylpropanoids esterified with sucrose was essential for higher antimicrobial activity of vanicosides and also acetylation of sucrose might affect the activity against the bacterium.

Naturally Occurring Antidotes against Benzimidazole Fungicides

TLC bioautography using precoated glass thin-layer plates impregnated with benomyl or carbendazim (MBC), and Cladosporium herbarum as a test fungus was evaluated as a facil way to detect plant secondary metabolites antidoting against benzimidazole fungicides. In addition to emodin and a-tocopherol from Polygonum sachalinense, three phenolics, 3,5-dihydroxy- 4-methylstilbene and 5-methoxy-6,7-methylenedioxyflavone from P. lapathifolium, and 2,6-dim ethoxybenzoquinone from P. thunbergii were isolated and characterized as new benzimidazole antidotes. Emodin exhibited the antidoting activity not only against benomyl but also against carbendazim (M BC), thiabendazole (TBZ), thiophanate-methyl and nocodazole. Furthermore, emodin showed antidoting activity against MBC in the wild-type Neurospora crassa and against diethofencarb in the mutant of N. crassa resistant to benzimidazole fungicides but highly susceptible to diethofencarb

Photosynthetic Adaptation to Light Intensity in Sakhalin Knotweed (Polygonum sachalinense)

The capacity for photosynthetic acclimation to light intensity in Sakhalin knotweed (Polygonum sachalinense F. Schmidt) was studied by growing plants in four light environments [out-of-doors in full sun and under 50% shade, and in a growth chamber at 800 μE m2 sec-1 photosynthetically active radiation, 400 to 700 nm (PAR) and 150 μE m-2 sec-1 PAR], and then determining, with an infrared gas analyzer (IRGA), the photosynthetic rates of single leaves exposed to a range of light intensities from 100 to 2000 μE m2 sec-1 PAR. The plants grown in high light had higher photosynthetic rates throughout the range of 100 to 2000 μE M-2 sec-1 PAR. Maximum photosynthetic rates were 37 mg CO2 dm-2 h-1 for plants grown in full sun out-of-doors and 16.5 mg CO2 dm-2 h-1 for plants grown in low light in the growth chamber. There was no indication of positive adaptation to low light intensity in Sakhalin knotweed. Differences in light-saturated photosynthetic rates were closely related to differences in mesophyll conductance and chlorophyll content per unit leaf area.