Proline and Glutamine Improve in vitro Callus Induction and Subsequent Shooting in Rice

This study was conducted to evaluate the effects of proline and glutamine on in vitro callus induction and subsequent regeneration and to develop a reproducible and highly efficient plant regeneration protocol in four rice genotypes, viz. Pawana, Jaya, Indrayani and Ambemohar. Considerable variation in response to plant growth regulators and amino acid supplements used was observed in all the four genotypes. Medium supplemented with proline and glutamine was shown to be superior to medium without proline and glutamine. The best callusing from mature embryo was observed on Murashige and Skoog(MS) medium supplemented with 2.0 mg/L 2,4-dichlorophenoxyacetic acid(2,4-D), 500 mg/L proline and 500 mg/L glutamine. Shoot induction was higher in the callus obtained from medium supplemented with 500 mg/L proline and 500 mg/L glutamine. The highest shoot regeneration frequency(83.2%) was observed on MS medium with 2.0 mg/L benzylaminopurine, 0.5 mg/L 1-naphthaleneacetic acid, 500 mg/L proline, and 500 mg/L glutamine in the callus obtained from MS medium supplemented with 2.0 mg/L 2,4-D, 500 mg/L proline and 500 mg/L glutamine. Among the four genotypes, Pawana has the highest regeneration efficiency(83.2%), whereas the regeneration efficiency of the rest three rice genotypes was in the range of 32.0% to 72.3%. This optimized regeneration protocol can be efficiently used for Agrobacterium mediated genetic transformation in rice.     

Canopy photosynthesis,stomatal conductance and yield ofSolanum tuberosum grown in a warm climate

Selected potato (Solanum tuberosum L.) genotypes were grown in the field from May to September during 1984 and 1985, to study their growth and gas exchange responses in a warm climate. The parameters measured were leaf area index (LAI), canopy photosynthesis on ground area basis (CPn-Ga), stomatal conductance, dry matter partitioning and yield. The LAI ranged from 1.40 for Dakchip to 6.60 for Pungo during August 1984. The LAI also differed significantly among the potato genotypes for the three samplings during 1985. Atlantic, Chipbelle and DTO-33 showed no decline in their LAI up to 73 days after planting (DAP), indicating a better heat-stress tolerance response than the other genotypes. During both years, CPn-Ga differed significantly among the genotypes and Pungo had higher CPn-Ga than all the other genotypes. Mean CPn-Ga rates were 1.72 and 4.34 g CO₂ m^?2hr^?1 during 1984 and 1985, respectively. Mean adaxial and abaxial stomatal conductances were 0.86 and 1.46 cm sec^?1, during 1984, and stomatal conductances were similar for both years. Stomatal conductance did not appear to limit gas exchange in potato leaves. Dry matter partitioning to tubers ranged from 8.9% for Pungo to 55.5% for Atlantic 67 DAP during 1984. At final harvest, July 19, 1985, dry matter partitioning to tubers varied from 47.5% for Pungo to 69.9% for Chipbelle. The tuber yield ranged from 9.6 to 27.8 MT/ha. This study indicated that Atlantic and La Chipper have potential for growing in a warm climate.     

Estimating duration and intensity of Neoproterozoic snowball glaciations from Ir anomalies

The Neoproterozoic glaciations supposedly ended in a supergreenhouse environment, which led to rapid melting of the ice cover and precipitation of the so-called cap carbonates. If Earth was covered with ice, then extraterrestrial material would have accumulated on and within the ice and precipitated during rapid melting at the end of the glaciation. We found iridium (Ir) anomalies at the base of cap carbonates in three drill cores from the Eastern Congo craton. Our data confirm the presence of extended global Neoproterozoic glaciations and indicate that the duration of the Marinoan glacial episode was at least 3 million, and most likely 12 million, years.     

Growth and elemental composition of tomato as affected by fungicides and nitrogen sources

Tomato (Lycopersicon esculentum Mill.) plant growth and elemental composition were evaluated using three NH₄‐N:NO₃‐N form ratios with or without the fungicide benomyl, captan, lime‐sulfur, nitrapyrin, or terrazole in a greenhouse soil culture study. Nitrogen was applied weekly for 5 weeks providing a total of 115 mg N/kg. Each fungicide was applied at 0.25 mg/kg 3 days before transplanting, followed by 3 weekly applications with each N treatment. The largest shoot and root dry weights were obtained with 1:1 N form ratio. With 1:1 N ratio treatment, all chemicals significantly increased plant growth resulting in lower element concentrations relative to the untreated control. However, growth of plants receiving either 1:0 or 0:1 N ratio treatment was not affected by nitrapyrin and terrazole, but was restricted by benomyl, captan, or lime‐sulfur. Overall, elemental concentrations in the tissues of plants receiving either N form was related to the fungicide treatment.     

Fate of 14C-carbofuran in soils

The degradation of¹⁴ C-Carbofuran was studied in sterilized, unsterilized and green manure amended clay soil under moist and flooded conditions overa period of 30 days. The¹⁴ C mass balance showed that carbofuran did not undergo any degradation in sterilized moist soil. In sterilized flooded soil bound residues were formed to the extent of about 47% of the applied radioactivity at the end of 30 days. Carbofuran underwent considerable degradation in unsterilized moist and flooded soils. In moist soil about 48% of the applied¹⁴ C activity was recovered as bound activity while in flooded soil, about 23% of the activity was bound. Green manure amendment resulted in formation of more bound residues under moist conditions while it enhanced the degradation of carbofuran under flooded conditions. In flooded amended soil about 44% of the applied^l4 C-activity was recovered as against about 54% in the unamended flooded soil. The notable degradation products formed under flooded soil conditions were 3-keto carbofuran and 3-hydroxy carbofuran.     

Utilization of macro-nutrients and minerals in captive greater one-horned rhinoceros fed season-specific diets

This experiment was conducted to study nutrient and mineral utilization in greater one-horned rhinoceros fed season-specific diets. Nine adult greater one-horned rhinoceros (774–2407 kg BW) of Sanjay Gandhi Biological Park, Patna, Bihar, India, were used in this experiment. Three digestion trials of 60-d duration were conducted per animal, out of which 55 days was adaptation period and 5 days was collection period. The amount of concentrate was kept constant during all the trials. Green fodder sources were sugarcane, berseem (Trifolium alexndrinum) and chari (Sorghum bicolor) during trials I, II and III respectively. Green fodders were offered 20% in excess of previous day's intake in the afternoon. Apparent digestibility of dry matter and crude fibre was higher (p < .01) in group II as compared to other groups. Apparent digestibility of crude protein was lowest (p < .01) in group I, followed by group III, and the highest value was observed in group II. Apparent digestibility of Ca and P was lower in greater one-horned rhinoceros fed sugarcane and sorghum as green fodder source. In spite of this, sugarcane and sorghum-based diets were able to meet the requirement of Ca, P, Fe and Mn. Berseem supplied Ca in excess of requirement. All the diets were deficient in Zn. Hence, a suitable supplement of Zn should be added to the conventional zoo diet of greater one-horned rhinoceros.     

Influence of biocides on tomato nitrogen uptake and soil nitrification and denitirification

As a result of repeated applications, some fungicides may accumulate in the soil to levels high enough to have adverse effects on the activity of soil microorganisms and plant growth. Comparison of the effects of 10 mg kg^‐1 soil of the benlate, captan, and lime‐sulfur fungicides with the nitrification inhibitors (NI) nitrapyrin and terrazole on oxidation of NH₄ ⁺ in Tifton loamy sand (siliceous, thermic plinthic Typic Kandiudults) incubated at 30° C showed that benlate had no significant effects whereas captan inhibited nitrification 21% more than lime‐sulfur, but about 20% less than NI. Application of benlate enhanced NO₃ ^‐ reduction to N₂O and N₂ in liquid medium inoculated with soil whereas 50 and 100 mg L"¹ medium of captan and lime‐sulfur compared favorably with the NI in suppressing NO₃ ^‐ and NO₂ ^‐ reductions, but were less effective than the inhibitors when applied at the low rate of 10 mg L^‐1 medium. In a greenhouse study with tomato (Lycopersicon esculentum Mill. cv. ‘Better Boy'), weekly drench applications of 0.25 mg kg^‐1 soil of the test biocides for four weeks with three NH₄ ⁺‐N: NO₃ ^‐‐N ratios showed that benlate applied with 1: 0 N ratio and lime‐sulfur applied with 0: 1 N ratio restricted significantly the plant growth and N uptake. The largest root: shoot ratios, total plant dry weight, and N uptake were obtained with plants fertilized with 1: 1 N ratio in combination with the biocides.     

Engineering needs for potato production from true seed

Potatoes grown from true potato seed (TPS) are generally small and nonuniform in size and shape, compared to the ones produced conventionally from seed tubers. Potato production from TPS would be considerably less expensive than from seed tubers because of the negligible storage and handling costs of the TPS. Potato production from TPS would therefore have the greatest potential in the developing countries. In developed countries, this production method would have some potential in commercial production as well as in home gardening. Research related to the TPS potato production has been mostly directed toward investigating suitable cultural practices, screening breeding lines for higher yield and warm climate adaptability, weed control in the field, and other similar production areas. Research concerning mechanization of TPS potato production has been limited. Engineering input to the TPS potato production, handling and storage needs considerable attention to develop practical and economical practices. This paper highlights some research areas which the authors believe are worth investigating. Engineering research that is conducted at the Coastal Plain Experiment Station related to the TPS potato production has been outlined along with future plans.