Coal mining has caused severe damages to local environment, such as vegetation destruction and decrease in species diversity, which poses a great challenge for sustainable development. Ecological ...restoration, aiming to increase plant coverage and soil nutrients in coal-mine areas, is of great significance for improving environment quality. The restoration effort at the mineral resource-rich Gujiao coal mine is an example of ecological reconstruction in Shanxi Province. Staghorn sumac (Rhus typhina) was used as one of the main plant species for the ecological restoration in Gujiao. We surveyed staghorn sumac communities at four different restoration stages in a coal-gangue area in 2008 and 2009. The relationship between species diversity index and various environmental factors was analyzed using Pearson correlation coefficient. Based on the investigation of vegetation and soil properties, the following parameters were analyzed: reproduction of staghorn sumac; dynamics of community structure; plant species diversity; and soil condition. The results showed that significant changes in community structure, species composition, and diversity occurred during a 12years of restoration period. Pioneer species such as Artemisia scoparia and Setaria viridis played dominant roles at the early stage of restoration. However, these pioneer species were replaced by neutral species such as Poa sphondylodes and Bothriochloa ischaemum 5–8years later. Community coverage increased quickly because of a high reproduction rate of staghorn sumac, leading to a vertical decrease in light intensity from the canopy to the forest floor. Meanwhile, species numbers in the herb layer decreased substantially. Due to vigorous sprouting reproduction, staghorn sumac colonized new habitats and expanded its population rapidly. Staghorn sumac became an exclusive edificator of the community 12years later, and other species were greatly suppressed and nearly disappeared. Although soil organic matter, total N content, and available P content increased slightly during the restoration period, soil nutrients were still at a low level according to the soil fertility classification standards of the Second National Soil Survey in the 1980s. Therefore, the improvement to the soil condition was very limited. Pearson correlation suggested that soil fertility was a main factor influencing species diversity at the early stage of restoration, while light intensity became a leading factor after the canopy was closed. The vigorous sprouting reproduction of staghorn sumac was beneficial for increasing vegetation coverage of the coal-gangue area during a short time period. However, in the long term, staghorn sumac suppressed not only other species but also its own sprouts, resulting in high risks of degradation to the plant community. Therefore, caution should be taken when staghorn sumac is extensively planted for ecological reconstruction. Vegetation coverage, species diversity, and succession tendency should be used as main indices in an evaluation of ecological restoration. Moreover, our results suggest that low nutrient content is a disadvantage for vegetation restoration. Therefore, it is necessary to increase soil nutrients in ecological reconstruction in coal-gangue areas.
Pathways to complex gallotannins have been elucidated by enzyme studies, indicating that β-glucogallin is required as principal acyl donor. Evidence for the in vitro oxidation of pentagalloylglucose, ...the pivotal metabolite in this sequence, to ellagitannins, is presented. Immunohistochemical studies with antibodies raised against pentagalloylglucose and the galloyltransferase catalyzing the formation of this ester revealed that leaf mesophyll cell walls were a typical site of origin and deposition of hydrolyzable tannins. Seasonal changes of these compounds were studied with extracts from cell walls and intracellular space of oak leaves.
Enzymatic and immunohistochemical techniques have clarified the biosynthetic routes to gallotannins and ellagitannins and their subcellular deposition sites.
Leaves of staghorn sumac (
Rhus typhina) contain several galloyltransferases that catalyze the β-glucogallin dependent transformation of 1,2,3,4,6-pentagalloylglucose to gallotannins. Among these, an ...enzyme has been isolated that preferentially acylates the 3-position of the hexagalloylglucose, 3-
O-digalloyl-1,2,3,4,6-tetra-
O-galloylglucose, to afford the corresponding heptagalloylglucose being characterized by a 3-
O-
meta-trigalloyl side-chain. The enzyme, for which a
M
r of ca. 260,000 was determined, was purified to apparent homogeneity. SDS-PAGE suggested an α
4β
4-conformation of the native enzyme. It had a pH-optimum and an isolelectric point at pH 5.6, was most stable at pH 4.0–4.3, and displayed excellent heat-stability and in particular an extreme cold-tolerance. We propose the systematic name “β-glucogallin: hexagalloylglucose 3-
O-galloyltransferase” for this new enzyme.
A galloyltransferase from sumac leaves has been isolated and purified to homogeneity that preferentially acylates hexagalloylglucoses at the 3-position.
Leaves of Saghorn sumac (
Rhus typhina) contain. several isoenzymes that catalyze the R-glucogallin (1-
O-galloyl-β-D-glucose)-dependent transformation of 1,2,3,4,6-penta-
O-galloyl-β-D-glucose to ...complex gallotannins. Among these, a new galloyltransferase has been isolated that preferentially acylated the 4-position of the substrate, followed by substitution of the 2-position, thus yielding the hexa-galloylglucose, 4-
O-digalloyl-1,2,3,6-tetra-
O-galloyl-β-D-glucose, and the heptagalloylglucose, 2,4-di-
O-digalloyl-1,3,6-tri-
O-galloyl-β-D-glucose. The enzyme, for which a
M
r value of 360,000 was determined by gel filtration, was purified more than 500-fold to apparent homogeneity and was most reactive with hexagalloylglucose as acceptor substrate. The transferase had a pH optimum at 4.8, an isoelectric point at pH 4.95, was stable between pH 3.7 and 6.8, and proved comparatively heat-stable as shown by a temperature optimum of 40 °C and a half-maximal activity at 64 °C.
U -
C-Labelled 1,2,3,4,6-penta-O-galloyl-β-ᴅ-glucose was prepared by photoassimilation of
CO
with leaves from staghorn sumac (Rhus typhina) in the presence of the herbicide glyphosate. Extracts of ...the plant material were partitioned against ethyl acetate and chromatographed on Sephadex LH-20, yielding a series of crude tri-to decagalloylglucoses. The pentagalloylglucose fraction among these was further purified by HPLC to >99% purity and a specific radioactivity of 130 kBq (3.5 μCi) per μmol. The ratio of the radioactivities in the glucose and galloyl moieties, respectively, suggested a uniform labelling pattern of the product.
![Preparation of [14C]-Labell...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0939-5075_1865-7125/small "Preparation of [14C]-Labelled 1,2,3,4,6-Penta-O-Galloyl-β-ᴅ-Glucose and Related Gallotannins")