Mulberry (Morus species) leaf is the sole food for monophagous silkworms, Bombyx mori L. Abiotic stresses such as drought, salinity, and high temperature, significantly decrease mulberry productivity and post-harvest water loss from leaves influence silkworm growth and cocoon yield. Leaf surface properties regulate direct water loss through the cuticular layer. Leaf surface waxes, contribute for cuticular resistance and protect mesophyll cells from desiccation. In this study we attempted to overexpress AtSHN1, a transcription factor associated with epicuticular wax biosynthesis to increase leaf surface wax load in mulberry. Agrobacterium mediated in vitro transformation was carried out using hypocotyl and cotyledonary explants of Indian mulberry (cv. M5). Mulberry transgenic plants expressing AtSHN1 displayed dark green shiny appearance with increased leaf surface wax content. Scanning electron microscopy (SEM) and gas chromatograph–mass spectrometry (GC-MS) analysis showed change in pattern of surface wax deposition and significant change in wax composition in AtSHN1 overexpressors. Increased wax content altered leaf surface properties as there was significant difference in water droplet contact angle and diameter between transgenic and wild type plants. The transgenic plants showed significant improvement in leaf moisture retention capacity even 5 h after harvest and there was slow degradation of total buffer soluble protein in detached leaves compared to wild type. Silkworm bioassay did not indicate any undesirable effects on larval growth and cocoon yield. This study demonstrated that expression of AtSHN1, can increase surface wax load and reduce the post-harvest water loss in mulberry.

Lignin composition [syringyl/guaiacyl (S/G) ratio] and cellulose content in wood have an important bearing on pulp yield. This paper deals with the development of a calibration model for S/G ratio using five Eucalyptus species from different sites by diffuse reflectance near infrared spectroscopy. The model was constructed with 120 samples covering an S/G ratio range from 1.8 to 3.6, determined by pyrolysis-gas chromatography-mass spectrometry. The calibration plot has an R 2 value of 0.825 which was validated in E. camaldulensis, E. urophylla and E. pellita. Variation in S/G ratio was studied in more than 3000 E. camaldulensis trees across three diverse sites in southern India. The S/G ratio was lower in a low rainfall site (Mahabubnagar) compared to a higher rainfall site (Ongole). A positive correlation (R 2 = 0.72) was observed between S/G ratio and Kraft pulp yield in E. camaldulensis. Alkali consumption in Kraft pulping experiments was inversely proportional to the S/G ratio (R 2 = 0.914).

Potassium (K), one of the essential elements required for plant growth and development, determines leaf quality in tobacco ( Nicotiana tabacum L.). Potassium (K) levels are relatively high in black soils (vertisols), but K uptake is severely hindered by the presence of remarkably high levels of calcium and magnesium. Our major objective was to enhance potassium uptake in black soils, which cover the major tobacco growing regions of Andhra Pradesh, India. Among several agronomic inputs such as soil amendments, fertilizer application, and plant growth regulators, we found that foliar application of fulvic acid (FA), one of the most bioactive humate molecules, enhanced K levels in leaves. Using next-generation sequencing (NGS), we identified changes in expression levels of a number of genes related to metabolic pathways implicated in plant growth and nutrient uptake upon FA application. Interestingly, starch levels in leaves were reduced concomitant with an increase in K attributable to FA application. We attempt to provide plausible reasons for these observed FA-induced changes. Our results suggested that FA acts in a manner similar to the plant hormone auxin in tobacco, influencing expression of key genes encoding transporters and enzymes involved in K uptake and Color versions of one or more of the figures in the article can be found online at www. tandfonline.com/wcim. 740 Downloaded by [McMaster University] at 22:49 26 December 2014Fulvic Acid and Nutrient Uptake 741 starch metabolism. While fulvic acid has beneficial effects on plant growth, its mechanism of action is still unclear.

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The major tree species grown for pulp and paper industry in India are eucalypts, poplars, casuarinas, subabul and acacias. There is a growing demand for pulp and paper products with minimum adverse effect on natural forest and environment. Genetic transformation in these pulp woods are aimed at enhancing growth, wood characteristics and stress tolerance. However, genetic transformation of trees is a time consuming process because of long life cycle, recent domestication status and recalcitrance to in vitro procedures. Though various instances of incorporating desired trait by transformations in trees have been reported, the effect of genetically modified trees on surrounding ecosystems need further studies. Efforts towards making transgenic trees should take in to consideration of alleviation of public concerns on pollen dispersal, contamination of wild germplasm and biosafety.