甘蔗茎分枝：稀有的形态分离

虽然在甘蔗同节上出现多芽现象已被报道,但是却未曾发现同节多芽能独立生长成蔗茎的现象。文章阐述了2008～2009年度在甘蔗品种CoS 96268宿根蔗大田观察到的一株甘蔗植株上发生的独特的形态分离现象。在该株甘蔗地上部的第7、8节上均有2个芽,但第8节出现溢痕,将该节间分成不等的两部分;该分离部分在第9节间更为明显,并独立生长成两条蔗茎（分枝）,每条蔗茎均具有正常的节间形态。     

Correlation between morphological,chemical and RAPD markers for assessing genetic diversity in Withania somnifera (L.) Dunal

Genetic diversity among 14 Withania accessions were studied using morphological, chemical, and RAPD (Rapid Amplification of Polymorphic DNA) markers. On the basis of morphological variation and maximum assimilation of chemical constituents, wild accessions were considered elite as compared to cultivated. The molecular study showed that a total of 12 DNA fragments were amplified with five random decamer primers 75% of which were polymorphic. Genetic similarity matrix based on the Dice index detected coefficients ranging from 0.556 to 0.941. These coefficients were used to construct a dendrogram using unweighted pair group method with arithmetic mean (UPGMA). These accessions were clustered into two major groups; the first group included AGB-009, AGB-012, AGB-042, AGB-030, AGB-053, AGB-019, AGB-017, AGB-002, and AGB-003; the second included AGB-025, AGB-001, AGB-036, AGB-015, and AGB-055. The highest similarity among the Ashwagandha accessions was observed between AGB-009 and AGB-030, AGB-009 and AGB-012, AGB-042 and AGB-030, AGB-025 and AGB-001, AGB-036 and AGB-015, AGB-015 and AGB-055 and between AGB-015 and AGB-055. The most distant populations in the dendrogram were AGB-053 and AGB-055. The combination of morphological, chemical, and molecular markers assessment will be useful in studying the genetic diversity of Withania for identification, conservation, breeding, improvement activities, and in order to achieve elite type in terms of bioactive metabolites.     

Study on Sorption Characteristics of Uranium onto Biochar Derived from Eucalyptus Wood

In this study, the sorption characteristics of U(VI) onto eucalyptus biochar as a function of various operating parameters such as solution pH, initial metal ion concentration, contact time and ionic strength of the medium are reported. Biochar was characterised using various techniques such as CHNS element analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). SEM analysis showed the presence of micro- and macropores in the sorbent, and FTIR spectra confirmed the presence of functional groups like carboxylic (?COOH), hydroxyls(?OH), carbonyls(–C=O), etc. Maximum sorption of about 95% is found to occur in the pH range of 5 to 6. U(VI) sorption onto biochar reached equilibrium within 20 min at pH 5.5. The kinetic data were analysed using both pseudo-first-order and pseudo-second-order kinetic models, and the latter is found to be more appropriate to explain the observed kinetics. The equilibrium data were correlated with Langmuir and Freundlich models, and the maximum monolayer adsorption capacity obtained from the Langmuir model was 27.2 mg/g at 293 K. From EDS, FTIR and XPS measurements, it is found that the sorption process involves chemical interaction between the U(VI) and the surface functional groups on the adsorbent. Efficient removal of low level of uranium from ammonium diuranate supernatant demonstrates its utility as sorbent for waste water treatment.     

Desorption and transformation of zinc in a mollisol and its uptake by plants in a rice–wheat rotation fertilized with either zinc-enriched biosludge from molasses or with inorganic zinc

Laboratory and greenhouse investigations were carried out with ⁶⁵Zn-labeled sources to study the kinetics of desorption, transformation, and availability of Zn applied to soil as zinc-enriched biosludge from distillery molasses (ZEMB) or as zinc sulfate heptahydrate (ZSH). Desorption (0.5 to 72 h) of added Zn by the column method followed a biphasic kinetics with an initial (up to 12 h) faster phase followed by a slower desorption phase. The desorption rate coefficient (K) of the latter phase and the amount of Zn desorbed during 12 to 72 h were significantly higher with ZEMB than with ZSH. Sequential extraction of Zn added as ZEMB and ZSH showed that Zn added as ZEMB was present in higher proportion as water soluble + exchangeable, carbonate bound, organically bound, and reducible fractions than Zn applied as ZSH, which showed a higher proportion of residual fraction. Under greenhouse conditions, dry matter yield (35 days) and total Zn uptake by rice fertilized with ZSH applied at 5 kg Zn ha⁻¹ were statistically similar to those of rice treated with 2.5 kg Zn ha⁻¹ supplied as ZEMB. The highest Zn uptake (167.08 μg pot⁻¹) by rice was recorded in the treatment with 5 kg Zn ha⁻¹ as ZEMB. For wheat plants grown after the harvest of rice, significantly higher dry matter yield over control was recorded in the treatment with ZEMB applied at 5 kg Zn ha⁻¹ to rice. Total Zn uptake by wheat was statistically similar for both ZEMB and ZSH treatments at 5 kg Zn ha⁻¹ dose. Both zinc derived from fertilizer and the percent utilization of fertilizer Zn by rice and by the subsequent wheat crop were significantly higher with ZEMB than with ZSH. Patent filed No. 757/MUM/2007 dated 19.04.2007     

Impacts of Coriaria nepalensis colonization on vegetation structure and regeneration dynamics in a mixed conifer forest of Indian Central Himalaya

This study evaluated impacts of Coriaria nepalensis Wall.colonization on soil characteristics,vegetation structure and composition,regeneration status and expected future compositional changes,biomass and carbon stock in tree species of a mixed conifer forest of Central Himalaya.Three sites(1 ha each in an old landslide area)differing in Coriaria density(low:20 individuals ha^-1;medium:120 indiv.ha^-1;high:190 indiv.ha^-1)were used to enumerate the tree species.A total of 9 tree species and 2830 individuals were recorded from the three study sites that represented a gradient of Coriaria density.Number of species varied from 3 to 7 and the individuals from 690 to 1270 per site with lowest numbers at low Coriaria density and highest at medium Coriaria density.The number of seedlings increased with increasing Coriaria density,and the sites were unique in their seedling composition,indicating marked temporal dynamics.Site wise regeneration analysis showed that regeneration was poor at the site with low Coriaria density and good at the high-density site where many species emerged as seedlings.These results indicate that the ameliorative effects of Coriaria in terms of soil buildup,and accumulation of nutrients and organic matter helped more species to colonize the area.This facilitative ability of Coriaria can be used to restore degraded forest ecosystems of Indian Central Himalaya.     

Aggregation of rennet-altered casein micelles at low temperatures

The rennet-induced coagulation of bovine milk at 10 degrees C was investigated. The rate of change of absorbance at 600 nm was higher in milk renneted at 30 degrees C than that at 10 degrees C. The amount of casein sedimented on centrifuging skim milk at 5000g for 1 h at 10 degrees C increased with time after renneting. The viscosity of milk at 10 degrees C at low shear rates did not change significantly until 10 h after rennet addition, but it increased markedly after 20 h. Smaller particles in milk at 10 degrees C disappeared slowly over 36 h after rennet addition and aggregated into larger particles. These results suggested that casein micelles in milk aggregate at low temperatures. Reasons for the slow aggregation of milk renneted at 10 degrees C were investigated by inhibiting chymosin activity by pepstatin A. It is likely that beta-casein, or its hydrolysis, plays a role in aggregation of rennet-altered casein micelles at low temperatures.     

Factors affecting the retention of rennet in cheese curd

The coagulant retained in cheese curd is a major contributor to proteolysis during ripening. The objective of this study was to quantify the effects of several milk-related factors and parameters during cheese manufacture on the retention of coagulant in cheese curd. The amount of coagulant retained in curd was determined by its activity on a synthetic heptapeptide (Pro-Thr-Glu-Phe-[NO2-Phe]-Arg-Leu) using reversed-phase HPLC. The retention of chymosin in cheese curd increased significantly when the pH of milk was reduced at rennet addition below pH 6.1, the pH at whey drainage below pH 5.7, or the average casein micelle size in milk and when the ionic strength of milk was increased. The casein content of milk and the quantity of chymosin added to milk had no significant effect on the retention of chymosin in curd; the quantity of coagulant bound per gram of casein remained unchanged.     

Bioavailability of iron from wheat aegilops derivatives selected for high grain iron and protein contents

A coupled in vitro digestion/Caco-2 model was employed to assess iron bioavailability from wheat Aegilops derivatives selected for high iron and protein contents. The iron content in wheat genotypes used in this study correlated to a great extent with both protein (r = 0.80) and phytate (r = 0.68) contents. The iron bioavailability was based on Caco-2 cell ferritin formation from cooked digests of these derivatives (relative to WL711 control) and correlated positively with dialyzable iron (r = 0.63) and total iron content (r = 0.38) but not with the phytate content. The apparently decreased phytate/iron molar ratios, however, correlated negatively (r = -0.42) with the iron bioavailability, justifying the utilization of these parameters in biofortification programs. Iron bioavailability in the derivatives increased up to 1.5-fold, corresponding to a 1.5-2.2-fold increase observed in iron content over control. These data suggest that biofortification for iron proportionately leading to higher iron bioavailability will be the most feasible and cost-effective approach to combat micronutrient deficiency.