Search

Higher education is attracting more participation from an increasingly diverse student body. This diversity invites concerns on effective instructional delivery as the extent of students' engagement in learning now varies widely. Anecdotes on students' "undesirable" dispositions in course participation are not uncommon in higher education settings. This project set out to develop a questionnaire, developed for higher education in the Japanese context, on a range of student dispositions. The scale was a five-point Likert instrument designed to interpret learners' disengagement as an attitudinal disposition. The paper discusses the conceptual contours of disengagement as a student disposition that provided the basis for the context-specific scale items. It reports the procedures taken to obtain the factor structures of the dataset. The questionnaire was administered to 145 engineering students in Japan. An exploratory factor analysis revealed a five-factor solution--lack of commitment, distractedness, lack of preparedness, anti-social orientation, and lack of focus. Avenues for further research are suggested, and implications for practice are discussed.

Phosphorus is a major essential element in plants, and the absorption and transport of P are related to crop growth and productivity. Phosphate (Pi) is absorbed in the roots and transported to the shoot. Plants store surplus Pi in the vacuoles. The characteristics of Pi storage and turnover in various parts of the nodulated soybeans might be related to plant growth and P-use efficiency. This research focused on the changes in the Pi concentrations and Pi contents in each part of young soybean plants grown in Pi-sufficient (50 μM Pi) or Pi-deficient (0 μM Pi) conditions. Also, the Pi flux rate in xylem sap from roots to shoot was determined. The growth of the plants was the same after 7 days of Pi-sufficient and Pi-deficient treatments. During the Pi-deficient period, the Pi concentrations in the roots, leaves, and stems decreased significantly but did not deplete. The decrease in Pi concentration in nodules was much slower than the other parts. After the re-supply of 50 μM Pi in the solution, the Pi concentration increased only a little in each part of the Pi-deficient plants. The Pi concentration and Pi flux in the xylem sap quickly responded to the changes in the Pi concentration in the culture solution. [ABSTRACT FROM AUTHOR]

Although sorghum (Sorghum bicolor L.), a C4 grass plant, requires a higher iron (Fe) concentration in its leaves for sufficient growth compared to C3 grass plants, there are differences in Fe-deficiency tolerance among sorghum genotypes. C4 plant sorghum localizes Fe in bundle sheath (BS) cells as a major site for CO2 assimilation; however, the response of chloroplasts in BS cells to Fe deficiency remains unknown. We compared the allocation of Fe and proteins involved in the photosystems between Fe-deficiency-tolerant and Fe-deficiency-susceptible sorghum genotypes. The distribution patterns of the Fe-requiring core proteins of photosystems I and II were the same in both genotypes, whereas the tolerant genotype, line D100, allocated more Fe to the BS thylakoid membranes than the susceptible genotype, regardless of Fe nutritional status and leaf Fe content. These results suggest that the tolerant D100 sorghum line has mechanisms to supply sufficient Fe to the BS thylakoid membranes. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is an essential macro-element for plants, and understanding the characteristics of the absorption and transport of P in crops is essential. The low availability of P restricts the growth, nitrogen fixation, and yield of soybean plants. In this research, the radioisotope 33P was supplied to the culture solution to trace the absorption and transport of P in nodulated soybean plants monitored using an imaging plate. The absorption rate of 33P was almost the same under the light and dark conditions. The absorption rate of 33P in the decapitated roots was near to that of the intact plants under light. These results indicate that the P absorption is not affected by evapotranspiration over a short time period. Conversely, the 33P transport from the roots to the shoot was significantly lower under dark conditions than it was under light conditions, although some 33P reached the top of the shoots under both the light and dark conditions. The transport of P to the shoots depends on the transpiration supplemented by the root pressure. The multiplication value of the 33P concentration in the xylem sap and transpiration rate was almost equivalent to the transport rate of 33P in the intact shoots. This value may be adaptable and used to estimate the transport rate of P for the diagnosis. [ABSTRACT FROM AUTHOR]

Nitrate concentration is variable in soils, so the absorbed N from roots in a high-nitrate site is recycled from shoots to the root parts in N-poor niche. In this report, the absorption, transport, and recycling of N derived from 15N-labeled nitrate were investigated with split-root systems of nodulated soybean. The NO3− accumulated in the root in 5 mM NO3− solution; however, it was not detected in the roots and nodules in an N-free pot, indicating that NO3− itself is not recycled from leaves to underground parts. The total amount of 15NO3− absorption from 2 to 4 days of the plant with the N-free opposite half-root accelerated by 40% compared with both half-roots that received NO3−. This result might be due to the compensation for the N demand under one half-root could absorb NO3−. About 2–3% of the absorbed 15N was recycled to the opposite half-root, irrespective of N-free or NO3− solution, suggesting that N recycling from leaves to the roots was not affected by the presence or absence of NO3−. Concentrations of asparagine increased in the half-roots supplied with NO3− but not in N-free half-roots, suggesting that asparagine may not be a systemic signal for N status. [ABSTRACT FROM AUTHOR]