Mekanisme Reaksi Asam Borat Dengan Produk Radiolisis Akibat Radiasi Sinar- Pada Temperatur 25oc

MEKANISME REAKSI ASAM BORAT DENGAN PRODUK RADIOLISIS AKIBAT RADIASI SINAR- PADA TEMPERATUR 25OC. Telah dilakukan simulasi yang bertujuan untuk memahami mekanisme reaksi antara asam borat (H3BO3) yang ditambahkan kedalam air pendingin primer PWR dengan produk radiolisis akibat radiasi dengan sinar- pada temperatur 25oC. Simulasi dilakukan dengan menggunakan perangkat lunak ‘Facsimile\u27 yang berbasis kinetika reaksi yang berkelanjutan. Sebagai masukan adalah set reaksi kimia yang terdiri dari 61 jenis reaksi dengan konstanta kecepatan reaksinya, nilai-G spesi radiolisis akibat radiasi sinar-, laju dosis 10 dan 104 Gy/s, konsentrasi awal oksigen yang berhubungan dengan sistem aerasi (0,25M), deaerasi dan konsentrasi asam borat hingga konsentrasi 1M. Luaran di program berupa seri Perubahan konsentrasi vs waktu iradiasi. Data luaran kemudian diolah menggunakan perangkat pembuat grafik ‘Origin\u27. Validasi dilakukan dengan membandingkannya dengan hasil simulasi sebelumnya. Hasil validasi menunjukkan perbedaan yang tidak signifikan, sehingga diputuskan bahwa set reaksi sekarang adalah valid. Penambahan asam borat menekan konsentrasi oksigen secara signifikan. Hubungan kenaikan logaritmik penambahan konsentrasi H3BO3 vs produk oksigen menunjukkan hubungan linear yang menurun. Dari hasil simulasi dapat dipahami bahwa penambahan H3BO3 tidak hanya mengatur reaktivitas neutron pada temperatur 25oC tetapi juga memberikan imbas positif didalam menekan konsentrasi produk oksigen yang memegang peran penting di dalam proses korosi

Relative effects of Uniconazole p and other growth regulators on micropropagation ratio of yam (Dioscorea spp.) plantlets at different growth phases

Open Access JournalScarcity of seed, pest and diseases are major constraints to yam production. Tissue culture techniques of meristem culture combined with heat therapy have been used to produce high-yielding virus-tested plantlets of root crops, which are later multiplied through micropropagation. However, the micropropagation rate is low in yam. We investigated in vitro, the rate of production of new nodes at some Plant growth regulator regimes applied at specific growth phases of yam. Three concentrations each of uniconazole-p (UP), gibberellic, jasmonic (JA) and naphthalene acetic (NAA) acids were applied at single node and primary nodal complex (PNC) formation phases in a split-plot design using two genotypes each of white and water yams. Number of nodes per plantlet was recorded after 16 weeks. The number of new nodes varied significantly with genotype by growth phase interaction and the main effect of PGRs. After 16 weeks, the control, 1.7µM UP and 0.03µM JA had highest means of 7, 9 and 8 nodes per plantlet compared to 2-3 nodes in the GA treatments. Thus, 4,900, 8,100 and 6,400 plantlets can be obtained in I year from a 100-node plant. In D. alata genotypes, addition of PGRs at PNC doubled the number of nodes per plantlet relative to addition at single node stage, while the effect of stage varied with genotype in D. rotundata. There is an important role for GA and its inhibitor-UP on the rate of yam micropropagation. Optimum multiplication rates can be achieved if the right PGR is applied at a standardized growth phase of a particular genotype. Earliness of genotypes seems to be a major factor that will determine the timing of application of PGRs

Biomass production and nutrient use efficiency in white Guinea yam (Dioscorea rotundata Poir.) genotypes grown under contrasting soil mineral nutrient availability

Open Access Journal; Published online: 12 Oct 2022Yam (Dioscorea spp.) is of great importance to food security, especially in West Africa. However, the loss of soil fertility due to dwindling fallow lands with indigenous nutrient supply poses a challenge for yam cultivation. This study aimed to determine shoot and tuber biomass and nutrient use efficiency of white Guinea yam (Dioscorea rotundata) grown under low- and high-NPK conditions. Six white Guinea yam genotypes were used in field experiments conducted at Ibadan, Nigeria. Experiments were conducted with low soil NPK conditions with zero fertilizer input and high soil NPK conditions with mineral fertilizer input. Differences in response to soil NPK conditions, nutrient uptake, and nutrient use efficiency (apparent nutrient recovery efficiency) were observed among the tested genotypes. The genotypes TDr1499 and TDr1649, with high soil fertility susceptibility index (SFSI>1) and an increase in shoot and tuber biomass with fertilizer input, were recognized as susceptible to soil NPK conditions. There was a marked difference in apparent nutrient recovery efficiency; however, there was no varietal difference in physiological efficiency. Differences in apparent nutrient recovery efficiency among genotypes affected the fertilizer response (or susceptibility to soil NPK conditions) and the nutrient uptake. In contrast, the genotype TDr2029, with SFSI<1 and low reduction in shoot and tuber production between non-F and +F conditions, was recognized as a less susceptible genotype to soil NPK status. It was revealed that NPK fertilization did not reduce tuber dry matter content, regardless of genotype differences in susceptibility to soil NPK conditions. Hence, this could be helpful to farmers because it implies that yield can be increased without reducing tuber quality through a balanced application of soil nutrients. Our results highlight genotypic variation in sensitivity to the soil NPK availability, nutrient uptake, and nutrient use efficiency white Guinea yam. Differences in susceptibility to soil NPK conditions could be due to the genotypic variations in nutrient recovery efficiency white Guinea yam. Our findings could contribute to breeding programs for the development of improved white Guinea yam varieties that enhance productivity in low soil fertility conditions with low and high-input farming systems

Nutrient deficiency symptoms in yams (Dioscorea spp.)

Symptoms of nutritional deficiencies in D. alata and D. rotundata were observed when yam plants were grown in nutrient solutions from which any of the following had been omitted: N, P, K, Ca, Mg, Zn, Fe, B, Mn, Cu and Mo. The symptoms of deficiency of major elements were visible on plants of both species. The omission of Fe, B and Mo produced characteristic symptoms on the leaves of D. rotundata, but D. alata showed symptoms only in response to Fe deficiency. The omission of minor elements led to poor growth of the leaves, stems and roots. Nutrient deficiencies in yam plants could be diagnosed by visual symptoms in the field

Mini tuber production using yam (Dioscorea rotundata) vines

Mini tubers were produced from two varieties of Dioscorea rotundata using vine cuttings planted in carbonized rice husk or coco-peat in a screen house. The cuttings established better and produced more mini tubers in carbonized rice husk than in coco-peat 100 days after planting. Vine cuttings of seven varieties planted in carbonized rice husk produced 1.7 ± 0.8 mini tubers per cutting with mean weight of 3.0 ± 2.7 g and 70.1% moisture content. About 63% of these sprouted after 77–105 days of storage under ambient air temperature. Vine cuttings of D. rotundata can be used to produce mini tubers within 100–120 days that could be used in germplasm exchange and for production of seed yams