Petroleum flotation technique upgrades the germinability of <Emphasis Type="Italic">Casuarina equisetifolia</Emphasis> seed lots     

V. Sivakumar  R. Anandalakshmi  R. R. Warrier  B. G. Singh  Mulualem Tigabu  P. C. Odén 《New Forests》2007,34(3):281-291

The germination of Casuarina equisetifolia Forst seed lots is low (40–50%) even when freshly collected. This study aimed at upgrading the germination performance by removing non-germinable seeds using petroleum flotation technique. Seeds collected from 19 individual trees in seedling seed orchards in India were assessed using X-ray to determine the proportion of different seed lot fractions. The feasibility of petroleum ether as a separation medium was tested. Morphological characters of floating and sunken seeds were further studied using image analysis technique to examine their effects on the separation efficiency. The X-ray analysis revealed a large quantity of shrivelled, empty and insect-damaged seeds, altogether accounting 50%, which were the causes of low percentage germination of un-graded seed lots (48%). Petroleum flotation resulted in 90% germination in the sunken fraction and 4% in the floating fraction. The separation was distinct for most seed lots, except few seed lots that had relatively low germination in the sunken fractions and more than 10% germination in the floating fractions. As a whole, petroleum flotation appears to be a feasible technique to upgrade the germination of C. equisetifolia seed lots, and its efficacy is influenced by wing surface area, seed density and wing quotient of filled and empty seeds.  相似文献   

Antimicrobial activity of triterpenoids from Heliotropium ellipticum.     

S C Jain  B Singh  R Jain 《Fitoterapia》2001,72(6):666-668

Seven sterols and triterpenoids have been isolated from H. ellipticum and tested for their antimicrobial activity.  相似文献   

Seasonal dynamics of mineral N pools and N-mineralization in soils under homegarden trees in South Andaman,India     

Chandra Bhushan Pandey  Ram Bahal Rai  Lalita Singh 《Agroforestry Systems》2007,71(1):57-66

Agroforestry trees are now well known to play a central role in the build up of nutrients pools and their transformations similar to that of forest ecosystem, however, information on the potential of homegarden trees accumulating and releasing nitrogen (mineralization) is lacking. The present study reports seasonal variations in pool sizes of mineral N (NH₄⁺-N and NO₃⁻-N), and net N-mineralization rate in relation to rainfall and temperature under coconut (Cocos nucifera L.), clove (Eugenia caryophyllata Thunb) and nutmeg (Myristica fragrans Houtt. Nees) trees in a coconut-spice trees plantation for two annual cycles in the equatorial humid climate of South Andaman Island of India. Concentration of NH₄⁺-N was the highest during wet season (May–October) and the lowest during post-wet season (November–January) under all the tree species. On the contrary, concentration of NO₃⁻-N was the lowest in the wet season and the highest during the post-wet season. However, concentrations of the mineral N were the highest under the nutmeg and the lowest under the coconut trees. Like the pool sizes, mean annual mineralization was the highest under the nutmeg (561 mg kg⁻¹ yr⁻¹) and the lowest under the coconut trees (393 mg kg⁻¹ yr⁻¹). Rate of mineralization was the highest during the post-wet season and the lowest during the dry season (February–April) under all the tree species. High rainfall during the wet season, however, reduced the rate of nitrification under all the tree species. The mean annual mineralization was logarithmically related with rainfall amount and mean monthly temperature.  相似文献   

Armillaria root rot: Artificial inoculation and development of the disease in greenhouse1     

Pritam Singh 《Forest Pathology》1980,10(7):420-431

Inoculation of five softwood provenances have revealed that they vary considerably with regard to their percent infection, percent mortality, severity of disease symptoms and progress of infection. Sitka spruce was the most susceptible species and served as a better substrate for further development of mycelium and rhizomorphs as compared to Norway and black spruces and Scots pine. The fungus always entered through uninjured surface of root collar and/or roots, the latter with more than 2 mm diameter. There was a conspicuous reduction m the total and annual growth in height in A. mellea-infected seedlings.  相似文献   

A new phorbol diester from Aleurites moluccana     

Satyanarayana P  Kumar KA  Singh SK  Rao GN 《Fitoterapia》2001,72(3):304-306

A new phorbol diester, 13-O-myristyl-20-O-acetyl-12-deoxyphorbol (1), has been isolated from the benzene extract of the heartwood of Aleurites moluccana. In addition, hentriacontane, 6,7-dimethoxycoumarin, 5,6,7-trimethoxycoumarin and beta-sitostenone are being reported for the first time from this species.  相似文献   

Leaf conductance of primary and mature leaves ofPinus roxburghii: A comparison     

Donald B. Zobel  Satish C. Garkoti  Surendra P. Singh 《Journal of Forest Research》2001,6(1):1-5

We used a null-balance porometer to measure leaf conductance of mature and primary leaves of natural seedlings, saplings, and trees ofPinus roxburghii (chir) during autumn at four sites at 1,320–1,930 m elevation in the central Himalaya of India. Our hypothesis that primary leaves had higher leaf conductance than mature leaves (needles in fascicles), based on measurements in other pines, was rejected. Comparisons on the same saplings and seedlings showed lower leaf conductance for primary leaves than for mature leaves. Primary leaves on seedlings and saplings also did not consistently have higher leaf conductance than mature leaves on near-by trees. Mature leaves on seedlings, however, did often have higher conductance than mature leaves on nearby trees. Mean values for leaf conductance (mmol m⁻² s⁻¹, based on total leaf surface area) ranged from 42–82 for mature leaves on trees, 60–121 for mature leaves on seedlings, and 28–67 for primary leaves on seedlings. Compared to published values for other pine species, conductance of mature leaves ofP. roxburghii is relatively low. Funding for this study was provided by grants from the United States National Science Foundation, INT-9312052 and INT-9404043. We appreciate the review of an early draft by Barbara Bond.  相似文献   

Viability retention of seeds of shisham (Dalbergia sissoo Roxb.) on the trees after maturity     

K. S. Bangarwa  V. P. Singh  Sunil Puri 《New Forests》1996,11(1):85-91

In 1991 and 1992 studies on Dalbergia sissoo Roxb. showed the availability of ample amount of viable seed from November to May. Viability of seeds collected from December to March was more than 90 per cent. There was a slight but significant decrease in germination from March to may. Again germination per cent was slightly and significantly decreased from May to July. Thereafter, seed availability and viability were got drastically reduced. Sufficient viable seed of Dalbergia sissoo Roxb. can be collected at any time from November to July.  相似文献   

Large cardamom (Amomum subulatum Roxb.) plantation — An age old agroforestry system in Eastern Himalayas     

K. A. Singh  R. N. Rai  Patiram  D. T. Bhutia 《Agroforestry Systems》1989,9(3):241-257

Large cardamom (Amomum subulatum Roxb.) is a shade loving plant grown in the Indian hill states of Sikkim and Dargeeling district of West Bengal. About 30 important tree species are used to provide shade to the cardamom plants. Alnus nepalensis, a deciduous, nitrogen fixing and fast growing tree, is the species most commonly underplanted with cardamom. In addition to providing shade, it is also used for fuelwood. The old trees are cut and young plants coming up are allowed to grow in cyclic order. The quick decomposing leaf litter of A. nepalensis also fertilises the cardamom plants. The nitrogen added to the soil in this way has been found to be as high as 249 kg/ha. Large cardamom thrives well in a moist soil, which is maintained by water diverted from seasonal springs on the upper slopes. The system is well suited to conserving soil, water and tree cover of the characteristically steep slopes of the region. Moreover, the management inputs required for growing cardamom are low but the crop gives a higher financial return than rice or maize. The shade trees used in the system are also a major source of fuel, fodder and timber, especially as access to state owned forests is restricted by legislation. However, increasing incidence of viral chirkey and foorkey disease, panicle rot and capsule borer are reducing the cardamom productivity. It has been observed that integrating dairying and apiculture will further augment profitability from large cardamom agroforestry system.  相似文献   

Soil organic carbon and nitrogen pools in a chronosequence of poplar (Populus deltoides) plantations in alluvial soils of Punjab,India     

Shehnaz Sharma  Baljit Singh  Rajeev Sikka 《Agroforestry Systems》2015,89(6):1049-1063

  相似文献   

GROSS AND HISTOPATHOLOGIC CORRELATION OF LOW‐FIELD MAGNETIC RESONANCE IMAGING FINDINGS IN THE STIFLE OF ASYMPTOMATIC HORSES          下载免费PDF全文

Marcos P. Santos  Santiago D. Gutierrez‐Nibeyro  Alexia L. McKnight  Kuldeep Singh 《Veterinary radiology & ultrasound》2015,56(4):407-416

With the recent introduction of a 0.25T rotating MRI system, clinical evaluation of the equine stifle joint is now possible in the average equine athlete. A recent publication described common abnormalities of horses with stifle lameness detected with a low‐field MRI system; however, postmortem corroboration of the lesions detected was not possible. Therefore, our objective was to compare postmortem findings with low‐field MRI findings in equine cadaver stifle joints. Ten fresh cadaver stifle joints from horses without clinical signs of stifle disease were evaluated using low‐field MRI, gross dissection, and histopathology. In eight stifles, either the lateral or medial cranial meniscotibial ligament had an irregular shape, fiber separation, or moderate abnormal signal intensity (SI) on all sequences. In five stifles, the medial femoral condyle had articular cartilage fibrillation with or without an osteochondral defect over the weight bearing surface of the medial femoral condyle. All stifles had abnormal SI on all sequences within the patellar ligaments that corresponded with adipose tissue infiltrating between the collagen bundles. Other abnormalities identified included articular cartilage fibrillation of the tibial condyles in three stifles, and articular cartilage fibrillation with chondral defects in the patella in three stifles. All abnormalities detected with low‐field MRI were corroborated by gross dissection. Findings from the current study supported the use of low‐field MRI for detection of stifle joint lesions in horses and demonstrated that some stifle joint pathologies may be subclinical in horses.  相似文献