title: Winter Leaf Yellowing in 'Hass' Avocado

authors: Mandemaker, Andries Jan

subjects: Persea americana

abstract: The New Zealand avocado industry is worth $39.7 million in exports of 'Hass' avocados.  Crop yields grew steadily from 1996 to 2001 to reach an average of 8.86 tonnes/ha.  Since then however, crop yields have remained steady.  To increase returns to growers, crop yields must increase.  Avocado leaves in New Zealand become yellow in winter and it is hypothesised that chilling, followed by photoinhibition, is leading to photooxidation.  Leaf yellowing leads to reduced photosynthetic capacity and early leaf abscission, at a time when carbon fixation and carbohydrate reserves are needed to support developing flowers, subsequent fruit set and vegetative flush, in addition to the existing mature crop.

The focus of this research was to determine the underlying causes of yellowing in 'Hass' avocado leaves during winter.  It is suspected that it is a result of the creation of free-radical oxygen that causes photooxidation of leaf components under excess light during low temperature conditions, such as experienced on clear winter mornings in the Bay of Plenty.

An orchard in Katikati, in the Bay of Plenty, New Zealand was selected has it had a history of leaf yellowing.  Two open flow, differential gas exchange measurement systems, The CIRAS-1 and the CMS-400 were used to monitor leaf photosynthetic performance over the course of the 2006 winter, with particular focus on the month of August.  Chlorophyll a fluorescence was measured with a Walz Mini-PAM, leaf colour with a Minolta Chroma meter CR-200b and chlorophyll content with Minolta SPAD chlorophyll meter (in addition to traditional extraction techniques).

There was conclusive evidence that the cold nights resulted in decreased net photosynthesis over the winter, with the depression starting in May and ending around the middle of August, dates that coincide closely with the period when days with mean temperatures less than 10 C occurred.  The decrease in photosynthesis appears to be due to a direct effect on the carbon reduction pathway and in unusual in that full recovery seems to occur at the same time during the day. No photodamage of significance was found and the avocado seems to be highly protected against high light when photosynthesis is inhibited.  This investigation found that leaf yellowing is not caused by photodamage following depressed photosynthesis.

A new hypothesis is proposed which suggests that leaf yellowing is produced by the re-allocation of nitrogen  from leaves during cold weather during flowering.  It is suggested that the chilled leaves are seen as unproductive, old or shaded leaves by the plant and nutrient resources are re-allocated away from these leaves.

A foliar application of 1% low biuret urea and 0.5% magnesium sulphate is currently used by avocado growers to restore leaf colour in leaves that have become yellow over winter.  An experiment was carried out on yellowed leaves on 23rd August 2006 to determine the effectiveness of the treatment.  This study concluded that the treatment was able to restore some leaf colour, but had no effect on leaf photosynthetic function.

text: Winter Leaf Yellowing in 'Hass' Avocado The New Zealand avocado industry is worth $39.7 million in exports of 'Hass' avocados.  Crop yields grew steadily from 1996 to 2001 to reach an average of 8.86 tonnes/ha.  Since then however, crop yields have remained steady.  To increase returns to growers, crop yields must increase.  Avocado leaves in New Zealand become yellow in winter and it is hypothesised that chilling, followed by photoinhibition, is leading to photooxidation.  Leaf yellowing leads to reduced photosynthetic capacity and early leaf abscission, at a time when carbon fixation and carbohydrate reserves are needed to support developing flowers, subsequent fruit set and vegetative flush, in addition to the existing mature crop.

The focus of this research was to determine the underlying causes of yellowing in 'Hass' avocado leaves during winter.  It is suspected that it is a result of the creation of free-radical oxygen that causes photooxidation of leaf components under excess light during low temperature conditions, such as experienced on clear winter mornings in the Bay of Plenty.

An orchard in Katikati, in the Bay of Plenty, New Zealand was selected has it had a history of leaf yellowing.  Two open flow, differential gas exchange measurement systems, The CIRAS-1 and the CMS-400 were used to monitor leaf photosynthetic performance over the course of the 2006 winter, with particular focus on the month of August.  Chlorophyll a fluorescence was measured with a Walz Mini-PAM, leaf colour with a Minolta Chroma meter CR-200b and chlorophyll content with Minolta SPAD chlorophyll meter (in addition to traditional extraction techniques).

There was conclusive evidence that the cold nights resulted in decreased net photosynthesis over the winter, with the depression starting in May and ending around the middle of August, dates that coincide closely with the period when days with mean temperatures less than 10 C occurred.  The decrease in photosynthesis appears to be due to a direct effect on the carbon reduction pathway and in unusual in that full recovery seems to occur at the same time during the day. No photodamage of significance was found and the avocado seems to be highly protected against high light when photosynthesis is inhibited.  This investigation found that leaf yellowing is not caused by photodamage following depressed photosynthesis.

A new hypothesis is proposed which suggests that leaf yellowing is produced by the re-allocation of nitrogen  from leaves during cold weather during flowering.  It is suggested that the chilled leaves are seen as unproductive, old or shaded leaves by the plant and nutrient resources are re-allocated away from these leaves.

A foliar application of 1% low biuret urea and 0.5% magnesium sulphate is currently used by avocado growers to restore leaf colour in leaves that have become yellow over winter.  An experiment was carried out on yellowed leaves on 23rd August 2006 to determine the effectiveness of the treatment.  This study concluded that the treatment was able to restore some leaf colour, but had no effect on leaf photosynthetic function.

year: 2007

title: Chinese and English language versions: intellectual capital disclosure

authors: Liao, Likang

subjects: accounting

abstract: Purpose – The paper of this paper is to assess the extent and quality of IC disclosure in the Chinese and English language versions of the annual reports of 50 Chinese companies which are dual listed in both Chinese Mainland and Hong Kong stock markets.

Design/methodology/approach – An IC disclosure index is constructed. Content analysis is used to code the 100 annual reports in accordance to a five-point scale.

Findings – The Chinese version annual reports disclose more internal capital than the English versions, yet the English versions showed greater external capital. There was found to be a strong relationship between type of industries, the size of companies and the level of IC disclosure.

Research limitations/implications – The paper only examines one year's annual reports of the top 50 Chinese companies by market capitalisation.

Practical implications – It is hoped that by highlighting the IC disclosure of companies in China this will raise the level of debate around this issue and will lead to greater disclosure transparency of company reporting.

Originality/value – This is the first research study that compares the IC disclosure in different language versions of annual reports of Chinese companies as well as testing for the effects of company characteristics. It is also the first study that uses three different weighting methods to measure disclosure quality.

text: Chinese and English language versions: intellectual capital disclosure Purpose – The paper of this paper is to assess the extent and quality of IC disclosure in the Chinese and English language versions of the annual reports of 50 Chinese companies which are dual listed in both Chinese Mainland and Hong Kong stock markets.

Design/methodology/approach – An IC disclosure index is constructed. Content analysis is used to code the 100 annual reports in accordance to a five-point scale.

Findings – The Chinese version annual reports disclose more internal capital than the English versions, yet the English versions showed greater external capital. There was found to be a strong relationship between type of industries, the size of companies and the level of IC disclosure.

Research limitations/implications – The paper only examines one year's annual reports of the top 50 Chinese companies by market capitalisation.

Practical implications – It is hoped that by highlighting the IC disclosure of companies in China this will raise the level of debate around this issue and will lead to greater disclosure transparency of company reporting.

Originality/value – This is the first research study that compares the IC disclosure in different language versions of annual reports of Chinese companies as well as testing for the effects of company characteristics. It is also the first study that uses three different weighting methods to measure disclosure quality.

year: 2013

title: How institutions frame mātauranga Māori (Commissioned by Waikato Regional Council)

authors: Whaanga, Hēmi

abstract: The primary questions for this report are:
1) How is Mātauranga Māori framed by Institutions?
2) How is Mātauranga Māori being operationalised by Institutions in New Zealand?
Mātauranga Māori is the intellectual capital generated by whānau, hapū and Iwi over multiple generations. It is a shared-community knowledge that is embedded in lived experience and carried in stories, song, place names, dance, ceremonies, genealogies, memories, visions, prophesies, teachings and original instructions, as and learnt through observation and copying of other community members.
It is a holistic system of orally passed knowledge, concepts, beliefs and practice. Mātauranga Māori, mātauranga ā-iwi, mātauranga ā-hapū, and mātauranga ā-whānau are dynamic, innovative, and generative systems of knowledge. Mātauranga Māori has been defined, framed, and operationalised with varying success by Institutions. Although the overall definitions vary somewhat, the general premise is that these government agencies acknowledge that mātauranga Māori is Māori-specific knowledge that is adaptive and regionally distinct. This recognition is important as it reinforces the notion that Māori are not a homogenous group, and that mātauranga Māori will differ across Iwi.
For the vast majority of institutions, improving their understanding of mātauranga Māori is an important strategic aim that can help guide their decision making, management, and monitoring procedures. Achieving this aim helps recognise the innovative potential of Māori knowledge, its contribution to council activities, and the usefulness of culturally appropriate data.
This report has identified seven factors that contribute towards a framework of understanding:
1) Acknowledging contemporary relevance and application: Iwi partners value mātauranga
Māori not only for its historic significance but its contemporary relevance in times of political change. Legislative requirements, iwi expectations, and a desire to build respectful relationships also contribute to current moves to understand and incorporate mātauranga Māori across regional council planning and decision-making activities.
2) Acknowledging cultural validity: Mātauranga Māori informs not only traditional practices but also Māori and iwi participation within Council activities.
3) Accepting epistemological difference: Eurocentric values and scientific disciplines tend to have primacy in a regional council context in part through historical tendencies and political representation. Mātauranga Māori brings a different value set and way of understanding phenomena to the table.
4) Acknowledging mana whenua responsibility for mātauranga Māori: The management and use of mātauranga represents a core responsibility of mana whenua. Relocating mātauranga and responsibility to act as a kaitiaki from a whānau, hapū or iwi to an institution, is a sensitive topic. Mātauranga is often vested with specific people (kaitiaki) or with local whānau and hapū to ensure the responsibilities for protecting the environment remain with those that live there.
5) Developing a more nuanced understanding of mātauranga Māori: Developing a more nuanced understanding of the different disciplines and content that exist under the broad definition of mātauranga Māori is necessary if Councils are to incorporate mātauranga Māori across a greater range of their work programmes.

text: How institutions frame mātauranga Māori (Commissioned by Waikato Regional Council) The primary questions for this report are:
1) How is Mātauranga Māori framed by Institutions?
2) How is Mātauranga Māori being operationalised by Institutions in New Zealand?
Mātauranga Māori is the intellectual capital generated by whānau, hapū and Iwi over multiple generations. It is a shared-community knowledge that is embedded in lived experience and carried in stories, song, place names, dance, ceremonies, genealogies, memories, visions, prophesies, teachings and original instructions, as and learnt through observation and copying of other community members.
It is a holistic system of orally passed knowledge, concepts, beliefs and practice. Mātauranga Māori, mātauranga ā-iwi, mātauranga ā-hapū, and mātauranga ā-whānau are dynamic, innovative, and generative systems of knowledge. Mātauranga Māori has been defined, framed, and operationalised with varying success by Institutions. Although the overall definitions vary somewhat, the general premise is that these government agencies acknowledge that mātauranga Māori is Māori-specific knowledge that is adaptive and regionally distinct. This recognition is important as it reinforces the notion that Māori are not a homogenous group, and that mātauranga Māori will differ across Iwi.
For the vast majority of institutions, improving their understanding of mātauranga Māori is an important strategic aim that can help guide their decision making, management, and monitoring procedures. Achieving this aim helps recognise the innovative potential of Māori knowledge, its contribution to council activities, and the usefulness of culturally appropriate data.
This report has identified seven factors that contribute towards a framework of understanding:
1) Acknowledging contemporary relevance and application: Iwi partners value mātauranga
Māori not only for its historic significance but its contemporary relevance in times of political change. Legislative requirements, iwi expectations, and a desire to build respectful relationships also contribute to current moves to understand and incorporate mātauranga Māori across regional council planning and decision-making activities.
2) Acknowledging cultural validity: Mātauranga Māori informs not only traditional practices but also Māori and iwi participation within Council activities.
3) Accepting epistemological difference: Eurocentric values and scientific disciplines tend to have primacy in a regional council context in part through historical tendencies and political representation. Mātauranga Māori brings a different value set and way of understanding phenomena to the table.
4) Acknowledging mana whenua responsibility for mātauranga Māori: The management and use of mātauranga represents a core responsibility of mana whenua. Relocating mātauranga and responsibility to act as a kaitiaki from a whānau, hapū or iwi to an institution, is a sensitive topic. Mātauranga is often vested with specific people (kaitiaki) or with local whānau and hapū to ensure the responsibilities for protecting the environment remain with those that live there.
5) Developing a more nuanced understanding of mātauranga Māori: Developing a more nuanced understanding of the different disciplines and content that exist under the broad definition of mātauranga Māori is necessary if Councils are to incorporate mātauranga Māori across a greater range of their work programmes.

year: 2017