Biotization of in vitro oil palm (Elaeis guineensis Jacq.) and its plant-microbe interactions

Continuous discovery of novel in vitro plant culture practices is always essential to promote better plant growth in the shortest possible cultivation period. An alternative approach to conventional micropropagation practice could be achieved through biotization by inoculating selected Plant Growth Promoting Rhizobacteria (PGPR) into the plant tissue culture materials (e.g., callus, embryogenic callus, and plantlets). Such biotization process often allows the selected PGPR to form a sustaining population with various stages of in vitro plant tissues. During the biotization process, plant tissue culture material imposes developmental and metabolic changes and enhances its tolerance to abiotic and biotic stresses, thereby reducing mortality in the acclimatization and pre-nursery stages. Understanding the mechanisms is, therefore crucial for gaining insights into in vitro plant-microbe interactions. Studies of biochemical activities and compound identifications are always essential to evaluate in vitro plant-microbe interactions. Given the importance of biotization in promoting in vitro plant material growth, this review aims to provide a brief overview of the in vitro oil palm plant-microbe symbiosis system.

Salinity-Induced Physiological Changes in Pea (Pisum sativum L.): Germination Rate, Biomass Accumulation, Relative Water Content, Seedling Vigor and Salt Tolerance Index

Salinity affects and limits the yield potential of pulse crops. Therefore, an experiment was conducted to evaluate the salinity-induced physiological response of field peas by estimating the germination rate (%), accumulation of biomass, relative water content, and seedling vigor and salt tolerance index. The treatments included four salinity levels (NaCl) (i.e., 0 (control), 8, 12, and 16 dS m^-1, respectively) and eight field pea genotypes (i.e., BD4175, BD4182, BD4225, BD6944, BD4176, BD4193, BD4493, and BD4496). All treatments were arranged in a factorial completely randomized design and repeated four times. Results indicated that the percentage and rate of germination, percentage reduction of fresh and dry weight, relative water content, seedling vigor index, and salt tolerant index of all genotypes of field peas were influenced significantly by the different levels of salinity. The radicle and plumule of all field pea genotypes were damaged by applying 12 and 16 dS m^-1 salt stress. However, among these eight pea genotypes, two genotypes, namely BD4175 and BD4225, performed better under the 8 dS m^-1 level of salinity and these two genotypes may be recommended for cultivation in field conditions of saline coastal areas of Bangladesh, and can also be used in future breeding programs for the development of salt-tolerant pea cultivars.

Integrated Nutrient Management for Rice Yield, Soil Fertility, and Carbon Sequestration

Reliance on inorganic fertilizers with less or no use of organic fertilizers has impaired the productivity of soils worldwide. Therefore, the present study was conducted to quantify the effects of integrated nutrient management on rice yield, nutrient use efficiency, soil fertility, and carbon (C) sequestration in cultivated land. The experiment was designed with seven treatments comprising of a zero input control, recommended inorganic fertilizers (RD), poultry manure (PM) (5 t ha^-1) + 50% RD, PM (2.5 t ha^-1) + 75% RD, vermicompost (VC) (5 t ha^-1) + 50% RD, VC (2.5 t ha^-1) + 75% RD, and farmers' practice (FP) with three replications that were laid out in a randomized complete block design. The highest grain yield (6.16-6.27 t ha^-1) was attained when VC and PM were applied at the rate of 2.5 t ha^-1 along with 75% RD. Uptake of nutrients and their subsequent use efficiencies appeared higher and satisfactory from the combined application of organic and inorganic fertilizers. The addition of organic fertilizer significantly influenced the organic carbon, total carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, soil pH, phosphorus, potassium, sulfur, calcium, and magnesium contents in post-harvest soil, which indicated enhancement of soil fertility. The maximum value of the organic carbon stock (18.70 t ha^-1), total carbon stock (20.81 t ha^-1), and organic carbon sequestration (1.75 t ha^-1) was observed in poultry manure at the rate of 5 t ha^-1 with 50% RD. The soil bulk density decreased slightly more than that of the control, which indicated the improvement of the physical properties of soil using organic manures. Therefore, regular nourishment of soil with organic and inorganic fertilizers might help rejuvenate the soils and ensure agricultural sustainability.