Understanding mulching influences on nitrogen (N) activities in soil is important for developing N management strategies in dryland. A 3 year field experiment was conducted in the Loess Plateau of China to investigate the effects of mulching, N fertilizer application rate and plant density on winter wheat yield, N uptake by wheat and residual soil nitrate in a winter wheat-fallow system. The split plot design included four mulching methods (CK, no mulch; SM, straw mulch; FM, plastic film mulch; CM, combined mulch with plastic film and straw) as main plot treatments. Three N fertilizer rates (N0, 0 kg N ha -1 ; N120, 120 kg N ha -1 ; N240, 240 kg N ha -1 ) were sub-plot treatments and two wheat sowing densities (LD, low density, seeding rate = 180 kg ha -1 ; HD, high density, seeding rate = 225 kg ha -1 ) were sub-subplot treatments. The results showed that wheat yield, N uptake, and N use efficiency (NUE) were higher for FM and CM compared to CK. However, soil nitrate-N contents in the 0-200 cm soil profile were also higher for FM and CM compared to CK after the 3 year experiment. Wheat grain yields were higher for SM compared to CK only when high levels of nitrogen or high planting density were applied. Mulching did not have a significant effect on wheat yield, nitrogen uptake and NUE when soil water content at planting was much high. Wheat yield, N uptake, and residual nitrate in 0-200 cm were significantly higher for N240 compared to N120 and N0. Wheat yield and N uptake were also significantly higher for HD compared to LD. When 0 or 120 kg N ha -1 was applied, HD had more residual nitrate than LD while the reverse was true when 240 kg N ha -1 was applied. After 3 years, residual nitrate-N in 0-200 cm soil averaged 170 kg ha -1 , which was equivalent to *40% of the total N uptake by wheat in the three growing seasons.

Xyloglucans were isolated by sequential extraction of the cell walls of pea (Pisum sativum L. cv. Alaska) with a xyloglucan-specific endoglucanase and KOH. The xyloglucan content and xyloglucan-oligosaccharide composition were determined for fractions obtained from the elongating and non-elongating segments of pea stems grown in the light and in darkness. The results were consistent with the hypothesis that regulated growth of the cell wall depends on xyloglucan metabolism. Furthermore, the characterization of xyloglucan extracted from leaves of light-grown pea plants indicates that xyloglucan metabolism is tissue specific. Changes in xyloglucan subunit structure observed in elongating stems are consistent with the in muro realization of a metabolic pathway that was previously proposed solely on the basis of the in vitro activities of plant glycosyl hydrolases.

SummaryA basic, 51 kDa protein was puri®ed from suspension-cultured tomato and shown to inhibit the hydrolytic activity of a xyloglucan-speci®c endoglucanase (XEG) from the fungus Aspergillus aculeatus. The tomato (Lycopersicon esculentum) protein, termed XEG inhibitor protein (XEGIP), inhibits XEG activity by forming a 1 : 1 protein:protein complex with a K i % 0.5 nM. To our knowledge, XEGIP is the ®rst reported proteinaceous inhibitor of any endo-b-1,4-glucanase, including the cellulases. The cDNA encoding XEGIP was cloned and sequenced. Database analysis revealed homology with carrot extracellular dermal glycoprotein (EDGP), which has a putative role in plant defense. XEGIP also has sequence similarity to ESTs from a broad range of plant species, suggesting that XEGIP-like genes are widely distributed in the plant kingdom. Although Southern analysis detected only a single XEGIP gene in tomato, at least ®ve other XEGIP-like tomato sequences have been identi®ed. Similar small families of XEGIP-like sequences are present in other plants, including Arabidopsis. XEGIP also has some sequence similarity to two previously characterized proteins, basic globulin 7S protein from soybean and conglutin c from lupin. Several amino acids in the XEGIP sequence, notably 8 of the 12 cysteines, are generally conserved in all the XEGIP-like proteins we have encountered, suggesting a fundamental structural similarity. Northern analysis revealed that XEGIP is widely expressed in tomato vegetative tissues and is present in expanding and maturing fruit, but is downregulated during ripening.

Monometallic and bimetallic MOF-74-M (M = Mn, Co, Ni, Zn, MnCo, MnNi, and MnZn) catalysts were prepared by the solvothermal method for NH 3 -SCR. XRD, BET, SEM, and EDS-mapping tests indicate the successful synthesis of the MOF-74-M catalyst with uniform distribution of metal elements and large specific surface area, and the morphology is almost hexagonal. Adding Mn element to a single-metal catalyst can enhance activity, which is mainly because of the existence of various valence states of Mn so that it has excellent redox properties; the catalytic activity of water and sulfur resistance tests showed that the catalytic activity of MOF-74-M increases after adding a proper amount of SO 2 , mainly because of the increase in acidic sites. In situ DRIFTS results indicate that the low-temperature range of MOF-74-MnCo and MOF-74-Mn is dominated by the E−R mechanism and the high-temperature range is dominated by the L−H mechanism. The entire temperature range of MOF-74-Zn is dominated by the L−H mechanism. KEYWORDS: MOF-74, in situ DRIFTS, NH 3 -SCR, resistance of H 2 O and SO 2 , mechanism

TiO 2 -supported manganese catalysts have been widely investigated because of their unique catalytic properties. A series of Mn−Ce−Ti−O catalysts were synthesized by a modified sol−gel method. Mn atom doping into CT-0/1 samples results in anatase partly transforming into rutile and two-phase coexistence. X-ray photoelectron spectroscopy and NH 3 temperature programmed desorption analysis show that the reactions of Mn 3+ + Ti 4+ ↔ Mn 4+ + Ti 3+ and Ce 4+ + Mn 3+ ↔ Ce 3+ + Mn 4+ happened, which is propitious to generating plentiful oxygen defects and chemical adsorbed oxygen and beneficial for the oxidation of NO to NO 2 . In addition, doping of Mn atoms could produce more acid sites and increase the ability of adsorption NH 3 that reacted with NO 2 to achieve high performance of deNO x in a wide temperature window. In situ diffusion reflectance infrared Fourier transform spectroscopy shows that MCT-15/1 achieves unpredictable NH 3 selective catalytic reduction activity following transition from the Langmuir−Hinshelwood (L−H) mechanism to the Eley−Rideal (E−R) mechanism with rising temperature.