scholarly journals The effects of endophytic fungi of NZ terrestrial orchids: developing methods for conservation

2021 ◽  
Author(s):  
◽  
Jonathan Frericks
Keyword(s):  
New Zealand ◽  
Seed Germination ◽  
Seed Viability ◽  
Its Rdna ◽  
Small Scale ◽  
Gene Marker ◽  
Terrestrial Orchids ◽  
Symbiotic Fungi ◽  
Asian Pacific ◽  
Tulasnella Calospora

<p>Nearly 40% of New Zealand (NZ) orchid species are of conservation concern, some critically endangered, largely due to habitat loss. In NZ, there are currently no propagation programs for terrestrial orchids all of which rely on symbiotic fungi to provide the nutrients required for germination, and little is known about the specific fungal species that might make this possible.  To develop an understanding of the fungal interactions affecting recruitment in the field, a survey of endophytic fungal diversity from the roots of Chiloglottis valida, Microtis unifolia, Pterostylis banksii, Spiranthes novae-zelandiae and Thelymitra longifolia was carried out. The identification of fungi was assisted by obtaining sequences of the ITS rDNA gene marker. Seeds of M. unifolia, P. banksii, S. novae-zelandiae and T. longifolia were inoculated with cultured endophytes that were recovered from the roots of conspecific orchids, and their effect on seed germination evaluated. Seed viability using fluorescein diacetate was assayed on all species prior to all experiments and showed moderate to high viability scores for all species. Recovered endophytes belonged to the phyla Ascomycota, Basidiomycota, and Zygomycota. The effect of the different endophytes on seed germination was variable, with five inoculants exhibiting a positive response. Three inoculants had a consistent negative effect on seed germination.  The distribution of orchid symbiotic mycorrhizae in situ was investigated at Otari-Wilton’s Bush, Wellington, NZ. Mesh seed packets containing seed of M. unifolia and T. longifolia were interred for 150 days, along transects (≤ 1 metre) that originated at adult orchids at three sites, and an additional site with no adult orchids was used as a control. No small-scale patterns were detected; however, germination rates were higher at undisturbed sites. Seed viability was considerably reduced to <2% after five months under the soil suggesting M. unifolia and T. longifolia seeds do not persist in the seed bank beyond one growing season. Sequences of ITS rDNA indicate Tulasnella calospora assists in the germination of M. unifolia at this site.  Similarly, Tulasnella calospora promoted germination of the Nationally Vulnerable wetland species S. novae-zelandiae. Pelotons were isolated from the roots of S. novae-zelandiae plants from a wild population from the lower north island and cultured in Petri dishes. Germination of this orchid began after 30 days from inoculation when the pelotons are already observed inside the embryo. Chlorophyllus tissue was observed after c. 80 days of inoculation. The phylogenetic relationship of Asian-Pacific Spiranthes species with New Zealand Spiranthes was also investigated using nuclear (ITS) and chloroplast (trnL-trnF) DNA sequences. Phylogenetic analyses supported the recognition of Spiranthes novae-zelandiae ‘Motutangi’ as a distinct taxonomic unit. It was also found that the Asian-Pacific Spiranthes species are in need of taxonomic revision.  Methods used and developed in this thesis study could be used to identify potential orchid symbionts and pathogens, assess suitable potential relocation sites, and propagation of NZ orchids using symbiotic fungi for restoration and conservation purposes.</p>

scholarly journals The effects of endophytic fungi of NZ terrestrial orchids: developing methods for conservation

2021 ◽  
Author(s):  
◽  
Jonathan Frericks
Keyword(s):  
New Zealand ◽  
Seed Germination ◽  
Seed Viability ◽  
Its Rdna ◽  
Small Scale ◽  
Gene Marker ◽  
Terrestrial Orchids ◽  
Symbiotic Fungi ◽  
Asian Pacific ◽  
Tulasnella Calospora

<p>Nearly 40% of New Zealand (NZ) orchid species are of conservation concern, some critically endangered, largely due to habitat loss. In NZ, there are currently no propagation programs for terrestrial orchids all of which rely on symbiotic fungi to provide the nutrients required for germination, and little is known about the specific fungal species that might make this possible.  To develop an understanding of the fungal interactions affecting recruitment in the field, a survey of endophytic fungal diversity from the roots of Chiloglottis valida, Microtis unifolia, Pterostylis banksii, Spiranthes novae-zelandiae and Thelymitra longifolia was carried out. The identification of fungi was assisted by obtaining sequences of the ITS rDNA gene marker. Seeds of M. unifolia, P. banksii, S. novae-zelandiae and T. longifolia were inoculated with cultured endophytes that were recovered from the roots of conspecific orchids, and their effect on seed germination evaluated. Seed viability using fluorescein diacetate was assayed on all species prior to all experiments and showed moderate to high viability scores for all species. Recovered endophytes belonged to the phyla Ascomycota, Basidiomycota, and Zygomycota. The effect of the different endophytes on seed germination was variable, with five inoculants exhibiting a positive response. Three inoculants had a consistent negative effect on seed germination.  The distribution of orchid symbiotic mycorrhizae in situ was investigated at Otari-Wilton’s Bush, Wellington, NZ. Mesh seed packets containing seed of M. unifolia and T. longifolia were interred for 150 days, along transects (≤ 1 metre) that originated at adult orchids at three sites, and an additional site with no adult orchids was used as a control. No small-scale patterns were detected; however, germination rates were higher at undisturbed sites. Seed viability was considerably reduced to <2% after five months under the soil suggesting M. unifolia and T. longifolia seeds do not persist in the seed bank beyond one growing season. Sequences of ITS rDNA indicate Tulasnella calospora assists in the germination of M. unifolia at this site.  Similarly, Tulasnella calospora promoted germination of the Nationally Vulnerable wetland species S. novae-zelandiae. Pelotons were isolated from the roots of S. novae-zelandiae plants from a wild population from the lower north island and cultured in Petri dishes. Germination of this orchid began after 30 days from inoculation when the pelotons are already observed inside the embryo. Chlorophyllus tissue was observed after c. 80 days of inoculation. The phylogenetic relationship of Asian-Pacific Spiranthes species with New Zealand Spiranthes was also investigated using nuclear (ITS) and chloroplast (trnL-trnF) DNA sequences. Phylogenetic analyses supported the recognition of Spiranthes novae-zelandiae ‘Motutangi’ as a distinct taxonomic unit. It was also found that the Asian-Pacific Spiranthes species are in need of taxonomic revision.  Methods used and developed in this thesis study could be used to identify potential orchid symbionts and pathogens, assess suitable potential relocation sites, and propagation of NZ orchids using symbiotic fungi for restoration and conservation purposes.</p>

Automatic Milking Systems: an option to address the labour shortage on New Zealand dairy farms?

2002 ◽  
pp. 39-43
Author(s):  
J.G. Jago ◽  
M.W. Woolford
Keyword(s):  
New Zealand ◽  
Dairy Industry ◽  
Research Programme ◽  
Working Hours ◽  
Dairy Farms ◽  
Small Scale ◽  
Labour Shortage ◽  
Commercial Farms ◽  
Grazing Systems ◽  
Automatic Milking Systems

There is a growing shortage of labour within the dairy industry. To address this the industry needs to attract more people and/or reduce the labour requirements on dairy farms. Current milk harvesting techniques contribute to both the labour requirements and the current labour shortage within the industry as the process is labour-intensive and necessitates long and unsociable working hours. Automated milking systems (AMS) have been in operation, albeit on a small scale, on commercial farms in Europe for a decade and may have the potential to address labour issues within the New Zealand dairy industry. A research programme has been established (The Greenfield Project) which aims to determine the feasibility of automated milking under New Zealand dairying conditions. A Fullwoods MERLIN AMS has been installed on a protoype farmlet and is successfully milking a small herd of 41 cows. Progress from the prototype Greenfields system offers considerable potential for implementing AMS in extensive grazing systems. Keywords: automated milking systems, dairy cattle, grazing, labour

scholarly journals Whole-genome sequencing from the New Zealand Saccharomyces cerevisiae population reveals the genomic impacts of novel microbial range expansion

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Peter Higgins ◽  
Cooper A Grace ◽  
Soon A Lee ◽  
Matthew R Goddard
Keyword(s):  
Saccharomyces Cerevisiae ◽  
New Zealand ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Range Expansion ◽  
Copy Number ◽  
Small Scale ◽  
Whole Genome ◽  
Copy Number Changes ◽  
The Impact

Abstract Saccharomyces cerevisiae is extensively utilized for commercial fermentation, and is also an important biological model; however, its ecology has only recently begun to be understood. Through the use of whole-genome sequencing, the species has been characterized into a number of distinct subpopulations, defined by geographical ranges and industrial uses. Here, the whole-genome sequences of 104 New Zealand (NZ) S. cerevisiae strains, including 52 novel genomes, are analyzed alongside 450 published sequences derived from various global locations. The impact of S. cerevisiae novel range expansion into NZ was investigated and these analyses reveal the positioning of NZ strains as a subgroup to the predominantly European/wine clade. A number of genomic differences with the European group correlate with range expansion into NZ, including 18 highly enriched single-nucleotide polymorphism (SNPs) and novel Ty1/2 insertions. While it is not possible to categorically determine if any genetic differences are due to stochastic process or the operations of natural selection, we suggest that the observation of NZ-specific copy number increases of four sugar transporter genes in the HXT family may reasonably represent an adaptation in the NZ S. cerevisiae subpopulation, and this correlates with the observations of copy number changes during adaptation in small-scale experimental evolution studies.

scholarly journals Seed longevity of maize conserved under germplasm bank conditions for up to 60 years

2021 ◽  
Author(s):  
Filippo Guzzon ◽  
Maraeva Gianella ◽  
Jose Alejandro Velazquez Juarez ◽  
Cesar Sanchez Cano ◽  
Denise E Costich
Keyword(s):  
Seed Germination ◽  
Plant Genetic Resources ◽  
Seed Viability ◽  
Storage Conditions ◽  
Seed Longevity ◽  
Germplasm Bank ◽  
Significant Difference ◽  
Different Temperatures ◽  
Germination Experiments

Abstract Background and Aims The long-term conservation of seeds of plant genetic resources is of key importance for food security and preservation of agrobiodiversity. Nevertheless, there is scarce information available about seed longevity of many crops under germplasm bank conditions. Methods Through germination experiments as well as the analysis of historical monitoring data, we studied the decline in viability manifested by 1000 maize (Zea mays subsp. mays) seed accessions conserved for an average of 48 years at the CIMMYT germplasm bank, the largest maize seedbank in the world, under two cold storage conditions: an active (–3 °C; intended for seed distribution) and a base conservation chamber (–15 °C; for long-term conservation). Key Results Seed lots stored in the active chamber had a significantly lower and more variable seed germination, averaging 81.4 %, as compared with the seed lots conserved in the base chamber, averaging 92.1 %. The average seed viability detected in this study was higher in comparison with that found in other seed longevity studies on maize conserved under similar conditions. A significant difference was detected in seed germination and longevity estimates (e.g. p85 and p50) among accessions. Correlating seed longevity with seed traits and passport data, grain type showed the strongest correlation, with flint varieties being longer lived than floury and dent types. Conclusions The more rapid loss of seed viability detected in the active chamber suggests that the seed conservation approach, based on the storage of the same seed accessions in two chambers with different temperatures, might be counterproductive for overall long-term conservation and that base conditions should be applied in both. The significant differences detected in seed longevity among accessions underscores that different viability monitoring and regeneration intervals should be applied to groups of accessions showing different longevity profiles.

scholarly journals Using Microwave Soil Heating to Inhibit Invasive Species Seed Germination

2017 ◽  
Vol 10 (3) ◽  
pp. 262-270 ◽  
Author(s):  
Mélissa De Wilde ◽  
Elise Buisson ◽  
Nicole Yavercovski ◽  
Loïc Willm ◽  
Livia Bieder ◽  
...  
Keyword(s):  
Invasive Species ◽  
Soil Moisture ◽  
Seed Germination ◽  
Invasive Plant ◽  
Organic Matter Content ◽  
Seed Viability ◽  
Germination Percentage ◽  
Matter Content ◽  
Burial Depth ◽  
Experimental Conditions

Successful invasive plant eradication is rare, because the methods used target the adult stage, not taking into account the development capacity of a large seedbank. Heating by microwave was considered, because it offers a means to quickly reach the temperature required for loss of seed viability and inhibition of germination. Previous results were not encouraging, because homogeneous and deep-wave penetration was not achieved, and the various parameters that can affect treatment effectiveness were incompletely addressed. This study aimed to determine, under experimental conditions, the best microwave treatment to inhibit invasive species seed germination in terms of power (2, 4, 6 kW) and duration (2, 4, 8 min) of treatments and depending on soil moisture (10%, 13%, 20%, 30%) and seed burial depth (2, 12 cm). Three invasive species were tested: Bohemian knotweed, giant goldenrod, and jimsonweed. The most effective treatments required relatively high power and duration (2kW8min, 4kW4min, 6kW2min, and 6kW4min; 4kW8min and 6kW8min were not tested for technical reasons), and their effectiveness diminished with increasing soil moisture with germination percentage between 0% and 2% for the lowest soil moisture, 0% and 56% for intermediate soil moisture, and 27% and 68% in control treatments. For the highest soil moisture, only 2kW8min and 4kW4min reduced germination percentage between 2% and 19%. Occasionally, germination of seeds located at the 12-cm depth was more strongly affected. Giant goldenrod seeds were the most sensitive, probably due to their small size. Results are promising and justify further experiments before developing a field microwave device to treat large volumes of soil infested by invasive seed efficiently and with reasonable energy requirements. Other types of soil, in terms of texture and organic matter content, should be tested in future experiments, because these factors influence soil water content and, consequently, microwave heating.

Control of chironomid midge larvae in wastewater stabilisation ponds: comparison of five compounds

2005 ◽  
Vol 51 (12) ◽  
pp. 191-199 ◽  
Author(s):  
R. Craggs ◽  
L. Golding ◽  
S. Clearwater ◽  
L. Susarla ◽  
W. Donovan
Keyword(s):  
New Zealand ◽  
Bacillus Thuringiensis ◽  
Urban Areas ◽  
Large Scale ◽  
Adult Emergence ◽  
Small Scale ◽  
Slight Reduction ◽  
Organic Loading ◽  
Valuable Component ◽  
Pre Treatment

Chironomid midge larvae are a valuable component of wastewater stabilisation pond (WSP) ecology. However, in high numbers, adult midge swarms can be a nuisance to near-by urban areas. Improving WSP treatment by incorporating aerobic or maturation ponds or by the addition of pre-treatment to reduce organic loading also increases the availability of aerobic sediment (midge larva habitat) in the pond system and the potential for midge nuisance problems. The efficacy of Maldison, an organophosphate traditionally used to control midge larvae in New Zealand WSPs, was compared to Bacillus thuringiensis var. israelensis (Bti), Methoprene, Pyriproxyfen and Diflubenzuron which are all more specific to insects and have fewer adverse environmental effects. Initial laboratory trials established the concentration of each compound required to achieve 95% control of the midge population. During 21-day small-scale trials within the WSP, Bti, Diflubenzuron and Maldison reduced live larvae numbers substantially (80–89%) compared to controls and adult midge emergence was markedly reduced by all compounds (72–96%). Large-scale trials with Bti (Vectobac® WG) powder (1000 μg/L) only caused a slight reduction in midge larvae numbers compared to controls and had little effect on adult emergence, however, Methoprene (Prolink XRG granules) (50 μgAI/L) reduced midge adult emergence by ∼80% over 25 days and has been used successfully to control several midge nuisance outbreaks.

scholarly journals Non-Deep Physiological Dormancy in Seed and Germination Requirements of Lysimachia coreana Nakai

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 490
Author(s):  
Saeng Geul Baek ◽  
Jin Hyun Im ◽  
Myeong Ja Kwak ◽  
Cho Hee Park ◽  
Mi Hyun Lee ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Germination Rate ◽  
Seed Viability ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Viability Test ◽  
Physiological Dormancy ◽  
Different Temperatures ◽  
Germination Requirements

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA3) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L−1 GA3. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA3 demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L−1 GA3 (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA3 treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L−1 GA3 treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.

scholarly journals Flowering, Fecundity, Seed Germination, and Seed Viability of Viburnum opulus L. Cultivars

2009 ◽  
Vol 27 (1) ◽  
pp. 31-36
Author(s):  
Janine R. Conklin ◽  
James C. Sellmer
Keyword(s):  
Seed Germination ◽  
Seed Production ◽  
Seed Viability ◽  
Biological Traits ◽  
Limited Information ◽  
Viable Seed ◽  
Invasive Potential ◽  
Short Term ◽  
Viburnum Opulus ◽  
Tetrazolium Test

Abstract Mature specimens of Viburnum opulus and cultivars ‘Leonard's Dwarf’ and ‘Roseum’ were assessed over 2 years for flower and seed production, seed germination, and seed viability as determined by a tetrazolium test to understand their invasive potential. ‘Aureum’, ‘Compactum’, ‘Losely's Compact’, ‘Nanum’, and ‘Xanthocarpum’ were also tested for germination and viability of seeds. Cultivars differed in flower and seed production, seed germination, and seed viability. ‘Roseum’ prolifically produced highly viable seed that germinated at moderate rates under greenhouse conditions (8,354, 100%, and 73%, respectively). Viburnum opulus and ‘Leonard's Dwarf’ produced fewer viable seed which showed moderate to low germination rates (609, 100%, and 53%; 712, 100%, and 5%, respectively). ‘Aureum’ and ‘Xanthocarpum’ seeds germinated at moderate rates (55 and 25%, respectively) and were highly viable (100%). ‘Compactum’, ‘Losely's Compact’, and ‘Nanum’ germinated at low rates or failed to germinate (0, 0, and 5%, respectively), yet seeds were moderately viable (37, 65, and 55%, respectively). Seeds of all cultivars germinated at low rates or failed to germinate at both outdoor sites (0 to 5%) which suggests these plants may be weakly invasive. Short-term studies on biological traits such as these provide only limited information to assess the invasive potential of cultivars.

scholarly journals Biology and survival of broom corn millet (Panicum miliaceum) seed

2011 ◽  
Vol 64 ◽  
pp. 142-148 ◽  
Author(s):  
T.K. James ◽  
A. Rahman ◽  
C.R. McGill ◽  
P.D. Trivedi
Keyword(s):  
Zea Mays ◽  
New Zealand ◽  
Seed Germination ◽  
Sweet Corn ◽  
Management Control ◽  
Panicum Miliaceum ◽  
Wild Type ◽  
Temperature Range ◽  
Control Options ◽  
Millet Seed

The wild type of broom corn millet (Panicum miliaceum) is a serious emerging weed currently prevalent in New Zealand sweet corn (Zea mays) crops This study shows its seed is nearly twice the weight of other common grass weeds and can germinate in the temperature range 1634C with 50 germination at 26C and greatest germination occurring at 31C At 15C it took 8 days for seedlings to emerge but required only 4 days at 25C Seed was able to emerge from depths of up to 170 mm in a range of soils Experiments showed that broom corn millet seed can persist in the soil for longer than 2 years in the field but is killed in silage stack and bales Immersion in stock effluent for up to three months reduced seed germination to less than 40 These characteristics are discussed in relation to herbicide and management control options for this weed

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