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Agricultural fallows, village commons and degraded forests, serve as important common community property resources throughout India, but due to their degraded status they are considered as ‘wastelands’, having little economic value and poor biodiversity. A study on secondary succession was conducted in agricultural fallows around Puducherry, India to review the negative image of ‘wastelands’. Chronosequences of four sites aged 2, 4, 10 and 50 years were used to investigate change in species composition and abundance, convergence with a nearby forest and to examine their economic use. A comparison of life‐forms, species richness and diversity indices showed that herbaceous species dominated up to 10th year sere, from which point in succession, woody species became more common. It was in the 50th year sere that shrubs and secondary tree species occurring in nucleated clumps became dominant. A cluster analysis based on Bray–Curtis similarity index shows a sequential development of vegetation through time, though 50th year plots showed no convergence with the Tropical dry evergreen forest (TDEF), but the principal component analysis demonstrates a change in community structure from grasslands to shrub and secondary tree species' dominance. Presence of adults of five primary forest species found in the clumps indicates a fast rate of secondary succession, considering that grazing and resource removal occurred in the sites. The potential value of the ‘wastelands’ is evident from the fact that 64 per cent of recorded species have economic use, which underlines the need for their sustainable utilization for better management of bioresources rather than converting them into monocultures. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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K. Kandiannan Utpala Parthasarathy K.S. Krishnamurthy C.K. Thankamani V. Srinivasan 《Scientia Horticulturae》2009,120(4):532-537
Leaf area estimation is an important biometrical observation one has to do for comparing plant growth in field and pot experiments. In this study, a leaf area estimation model was developed for ginger (Zingiber officinale Roscoe), using linear measurements of leaf length (L) and maximum width (W). Leaves from five ginger varieties (Varada, Rejatha, Mahima, Maran and Himachal) were used to develop the model in 2006–2007. The actual leaf area (LA) was measured with a leaf area meter (LI-3100, LI-COR, Lincoln, NE, USA) and taken as reference LA. The linear measurements were used to build linear (LA = a + b × L × W) and power models (LA = α × (L × W)β) for each variety, as the modeling among variety were not different from each other, data for all five varieties have been pooled and compared with earlier models by graphical procedures and statistical criteria such as Mean Square Error (MSE), Root Mean Square Error (RMSE) and Chi-square (χ2). The selected model was validated during 2007–2008. The validation data set was used to produce a validation model for each variety by re-estimating the model parameters to develop the estimation model and the models were compared for consistency. The predicted LA (PLA) was compared with observed LA (OLA) by graphical procedures and lack of agreement was evaluated by calculating the relative bias, estimated by the mean of differences (d) and the standard deviation (SD) of the differences. Normality test was carried out by Spearman's rank correlation coefficient (rs) and residuals were normally distributed. Finally, the proposed model for leaf area estimation of ginger is LA = −0.0146 + 0.6621 × L × W, R2 = 0.997. This model can be reliably used for estimating leaf area of ginger non-destructively. The same equation can be extrapolated to all varieties and land races of ginger as it is vegetatively propagated crop with narrow genetic variability. 相似文献
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We investigated the distribution and resource values of liana species assessed in six hill complexes of southern Eastern Ghats, India. 143 liana species (DBH (diameter at breast height) ≥1.5 cm) and 32,033 liana individuals were recorded from 110 transects (0.5 ha each covering 55 ha area) in the study sites. The resource values of lianas were broadly categorized into ecological and economic importance. About 90% (129) of liana species and 96% (30,564) of liana individuals were established ecological/economic values. Fruit rewards provided by 76 species and 20,325 individuals constituted the major resource of ecological importance. 82 species and 21,457 liana individuals are of economic importance as medicine, edible fruits, edible and medicinal values, and yet others are used for different domestic purposes including furniture, fuel wood, rope making etc.. Ecologically, the prevalence of succulent diaspores in lianas of Indian Eastern Ghats indicates the animal dependence of many liana species for dispersal and underlines the need for a holistic and whole-forest conservation approach in maintaining forest biodiversity. 相似文献
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The discovery of juvenile hormones (JH) and their synthetic analogs (JHA) generated excitement and hope that these compounds will replace first- and second-generation insecticides that have not so desirable environmental and human safety profiles. However, JHAs used commercially during the past four decades did not meet these expectations. The recent availability of advanced molecular and histological methods and the discovery of key players involved in JH action provided some insights into the functioning of JHA in a stage and species-specific manner. In this review, we will summarize recent findings and stage-specific action of JHA, focusing on three commercially used JHA, methoprene, hydroprene and pyriproxyfen and economically important pests, the red flour beetle, Tribolium castaneum, and the tobacco budworm, Heliothis virescens, and disease vector, the yellow fever mosquito, Aedes aegypti. 相似文献
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T. John Zachariah A.L. Safeer K. Jayarajan N.K. Leela T.M. Vipin K.V. Saji K.N. Shiva V.A. Parthasarathy K.P. Mammootty 《Scientia Horticulturae》2010
The biochemical component which attribute pungency to black pepper (Piper nigrum) is mainly the alkaloid piperine, the aroma and flavour are attributed by components like α- and β-pinenes, sabinene, myrcene, limonene, β-caryophyllene, camphene, etc. Our study revealed that the biochemical profile varies in the leaf and berries of black pepper. Total phenols, total starch, total carbohydrate and protein content from leaves and berries of selected 26 black pepper cultivars were evaluated. The concentration of oil, oleoresin, piperine and the essential oil constituents from both leaves and berries were also compared in these cultivars. Germacrene-D and elemol were found to be the major constituents of leaf oil. β-Caryophyllene was high in berries and it showed more variability in berries compared to leaf samples. Berry oil constituents namely, pinene, sabinene, myrcene and limonene were not detected in the leaf oil. Different leaf metabolites showed cumulative direct effect on berry constituents. 相似文献
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Cardamom lines, NKE 9 and NKE 12, resistant to Cardamom Mosaic Virus (CdMV) was crossed to two susceptible genotypes, viz., CCS 1 and RR 1 to determine the nature of inheritance of resistance. It was revealed from the results that the CdMV resistance in NKE 9 and NKE 12 is genetically governed. The F1 hybrids between resistant and susceptible genotypes were resistant. The segregation pattern for disease reaction in F2 and BC1 generations of the two crosses suggested that CdMV resistance in NKE 9 and NKE 12 could be controlled by two dominant complementary genes. Over all it could be hypothesized that the resistance to CdMV is quantitative, with possibly two major factors, and dependant on gene dosage with completely dominant gene action. This is the first report of CdMV inheritance in cardamom. 相似文献
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Lakshminarayana R Raju M Krishnakantha TP Baskaran V 《Journal of agricultural and food chemistry》2005,53(8):2838-2842
Leafy vegetables [Basella rubra L., Peucedanum sowa Roxb., Moringa oleifera Lam., Trigonella foenum-graecum L., Spinacia oleracea L., Sesbania grandiflora (L.) Poir., and Raphanus sativus L.] that are commonly used by the rural population in India were evaluated in terms of their main carotenoid pattern. The extracted carotenoids were purified by open column chromatography (OCC) on a neutral alumina column to verify their identity by their characteristic UV-visible absorption spectra. Reverse-phase high-performance liquid chromatography (HPLC) on a C18 column with UV-visible photodiode array detection under isocratic conditions was used for quantification of isolated carotenoids. Acetonitrile/methanol/dichloromethane (60:20:20 v/v/v) containing 0.1% ammonium acetate was used as a mobile phase. The major carotenoids identified by both methods were lutein, beta-carotene, violaxanthin, neoxanthin, and zeaxanthin. Among the carotenoids identified, lutein and beta-carotene levels were found to be higher in these leafy vegetables. Results show that P. sowa and S. oleracea are rich sources of lutein (77-92 mg/100 g of dry wt) and beta-carotene (36-44 mg/100 g of dry wt) compared with other leafy vegetables. The purity of carotenoids eluted by OCC was clarified by HPLC, and they were found to be 92% +/- 3% for neoxanthin, 94% +/- 2% for violaxanthin, 97% +/-2% for lutein and zeaxanthin, and 90% +/- 3% for beta-carotene. It could be recommended to use P. sowa and S. oleracea as rich sources of lutein and beta-carotene for health benefits. The OCC method proposed is relatively simple and provides purified carotenoids for feeding trials. 相似文献