A study of effects of low temperature stress on seed development and yield in wheat (Triticum aestivam L.) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Seed Technology at Massey University

Temperature affects the growth, development, fertility and yield of cereals. The degree of sterility and subsequent yield reduction caused by extreme temperature stress depends upon the minimum level and duration of the stress temperature applied and the stage of plant development at the time of stress. An experiment was conducted in which three low temperature regimes (-4°, -2°C and +3°C) were applied at 5 different stages of plant growth (from 1 day before anthesis to 9 days after anthesis) for a period of 6 hours with pre- and post- conditioning periods of 6 and 4 hours respectively. The results showed that the minimum temperature reached determined the nature and severity of temperature injury in Karamu wheat. Complete floret sterility was evident when a -4°C temperature was imposed at the pre-anthesis or anthesis stages of plant development; florets in any position of the head being equally affected. A -4°C temperature stress applied 3 days after anthesis produced 50% and 5% seed formation in primary and secondary heads, respectively. This seed formation mainly occurred in the basal florets of the apical and central spikelets of the head, however the seeds formed did not develop after stress and subsequent viable seed yield was zero. At the later stages, 6 or 9 days after anthesis a -4°C temperature stress had no significant effect on seed numbers. However there was a substantial negative effect on seed development and viability so that subsequent viable seed yield was zero. Temperature stresses of +3°C and -2°C had no significant effects on seed formation, development and viable seed yield when stresses were applied at any of the stages of plant development tested. The percentage of seed formation was highest in the two basal florets of the central and apical portions of the head compared to that in the two basal florets of the bottom of the head and to the distal florets of all spikelets. The percentage sterility in terms of relative sterility (percentage 'D + R' type ovules) and sterility index (percentage 'D' type ovules) was also described. It was found that in 'Karamu' wheat 16% to 33% rudimentary florets were a common feature, such structures included tiny basal, sterile spikelets and the terminal florets of all spikelets. Morphological and anatomical differences in ovules harvested at different stages of development from different treatments were observed. Ovules were classified into 6 groups for assessment of seed development. (A = apparently not fertilised, B = swollen and conical shaped, C = developing, D = shrivelled and shrunken, E = shrunken with reduced conical shape, R = rudimentary). Possible pathways to seed formation and development can be estimated from the data. A probable pathway to normal seed development is A to B to C. However, in the case of unsuccessful seed formation and development, the pathway is likely to be A to D,A to B to D or A to B to C to D. Further detailed electron microscope work is needed to enable a complete description and understanding of the pathways of seed development in stressed and unstressed plants. Such knowledge is needed to provide a logical basis for the development of cultivars with increased cold tolerance, fertility and yield

Modelling Dependency Structures Produced by the Introduction of a Flipped Classroom

Teaching processes have been changing in the lasts few decades from a traditional lecture-example-homework format to more active strategies to engage the students in the learning process. One of the most popular methodologies is the flipped classroom, where traditional structure of the course is turned over by moving out of the classroom, most basic knowledge acquisition. However, due to the workload involved in this kind of methodology, an objective analysis of the results should be carried out to assess whether the lecturer’s workload is worth the effort or not. In this paper, we compare the results obtained from two different methodologies: traditional lecturing and flipped classroom methodology, in terms of some performance indicators and an attitudinal survey, in an introductory statistics course for engineering students. Finally, we analysed the changes in the relationships among variables of interest when the traditional teaching was moved to a flipped classroom by using Bayesian networks

Mapping Progress : Human Rights and International Students in Australia

The rapid growth in international student numbers in Australia in the first decade of the  2000s was accompanied by a series of public crises. The most important of these was the outbreak in Melbourne Victoria and elsewhere of physical attacks on the students. Investigations at the time also pointed to cases of gross exploitation, an array of threats that severely compromised their human rights. This paper reviews and pursues the outcomes of a report prepared by the authors in 2010 for Universities Australia and the Human Rights Commission. The report reviewed social science research and proposed a series of priorities for human rights interventions that were part of the Human Rights Commission’s considerations.  New activity, following the innovation of having international students specifically considered by the Human Rights Commission, points to initiatives that have not fully addressed the wide range of questions at state

A Comparison of Machine-Learning Methods to Select Socioeconomic Indicators in Cultural Landscapes

Cultural landscapes are regarded to be complex socioecological systems that originated as a result of the interaction between humanity and nature across time. Cultural landscapes present complex-system properties, including nonlinear dynamics among their components. There is a close relationship between socioeconomy and landscape in cultural landscapes, so that changes in the socioeconomic dynamic have an effect on the structure and functionality of the landscape. Several numerical analyses have been carried out to study this relationship, with linear regression models being widely used. However, cultural landscapes comprise a considerable amount of elements and processes, whose interactions might not be properly captured by a linear model. In recent years, machine-learning techniques have increasingly been applied to the field of ecology to solve regression tasks. These techniques provide sound methods and algorithms for dealing with complex systems under uncertainty. The term ‘machine learning’ includes a wide variety of methods to learn models from data. In this paper, we study the relationship between socioeconomy and cultural landscape (in Andalusia, Spain) at two different spatial scales aiming at comparing different regression models from a predictive-accuracy point of view, including model trees and neural or Bayesian networks

The Role of Cultural Landscapes in the Delivery of Provisioning Ecosystem Services in Protected Areas

The aim of this paper is to assess and highlight the significance of cultural landscapes in protected areas, considering both biodiversity and the delivery of provisioning ecosystem services. In order to do that, we analyzed 26 protected areas in Andalusia (Spain), all of them Natural or National Parks, regarding some of their ecosystem services (agriculture, livestock grazing, microclimate regulation, environmental education and tourism) and diversity of the four terrestrial vertebrate classes: amphibians, reptiles, mammals, and birds. A cluster analysis was also run in order to group the 26 protected areas according to their dominant landscape. The results show that protected areas dominated by dehesa (a heterogeneous system containing different states of ecological maturity), or having strong presence of olive groves, present a larger area of delivery of provisioning ecosystem services, on average. These cultural landscapes play an essential role not only for biodiversity conservation but also as providers of provisioning ecosystem services

Social, behavioral, and cognitive influences on upper echelons during strategy process

This study reviews research on the social, behavioral, and cognitive influences on CEOs, top management teams (TMTs), and the CEO-TMT interface during strategic decision making. We identify the key issues examined in this research over the past 10 years and relate developments in the field to previous knowledge in this area. We also attempt to identify what constitutes an established body of knowledge in the field and, therefore, areas that need additional examination. Our review indicates that while there has been an explosion of research on the influence of CEO personality and TMT social processes on strategy process, much remains to be done in terms of examining CEO and TMT cognition, particularly at the level of the CEO-TMT interface

REPEATED ACUTE STRESS INDUCED ALTERATIONS IN CARBOHYDRATE METABOLISM IN RAT

Acute stress induced alterations in the activity levels of rate limiting enzymes and concentration of intermediates of different pathways of carbohydrate metabolism have been studied. Adult male Wistar rats were restrained (RS) for 1 h and after an interval of 4 h they were subjected to forced swimming (FS) exercise and appropriate controls were maintained. Five rats were killed before the commencement of the experiment (initial controls), 5 control and equal number of stressed rats were killed 2 h after RS and remaining 5 rats in each group were killed 4 h after FS. There was a significant increase in the adrenal 3β- hydroxy steroid dehydrogenase activity following RS, which showed further increase after FS compared to controls and thereby indicated stress response of rats. There was a significant increase in the blood glucose levels following RS which showed further increase and reached hyperglycemic condition after FS. The hyperglycemic condition due to stress was accompanied by significant increases in the activities of glutamate- pyruvate transaminase, glutamate- oxaloacetate transaminase, glucose -6- phosphatase and lactate dehydrogenase and significant decrease in the glucose -6- phosphate dehydrogenase and pyruvate dehydrogenase activities, whereas pyruvate kinase activity did not show any alteration compared to controls. Further, the glycogen and total protein contents of the liver were decreased whereas those of pyruvate and lactate showed significant increase compared to controls after RS as well as FS.The results put together indicate that acute stress induced hyperglycemia results due to increased gluconeogenesis and glycogenolysis without alteration in glycolysis. The study first time reveals that after first acute stress exposure, the subsequent stressful experience augments metabolic stress response leading to hyperglycemia. The results have relevance to human health as human beings are exposed to several stressors in a day and such an experience might lead to insulin resistance because prolonged hyperglycemic condition is known to cause insulin resistance