Evaluation of low temperature hardiness of strawberry plants under field and controlled conditions

1993 ◽  
Vol 73 (4) ◽  
pp. 1123-1125 ◽  
Author(s):  
J. M. Turner ◽  
K. K. Tanino ◽  
C. Stushnoff

When acclimated strawberry plants (Fragaria × ananassa Duch. ’Redcoat’) from the field were placed in a programmable freezer, mother strawberry crowns were as hardy or hardier than daughter crowns when frozen to −11 °C. However, under field conditions, daughter plants expressed consistently greater hardiness than mother plants. Mulching had no effect on daughter plant survival, whereas enhanced mother plant survival was observed. Field-growth habit of mother crowns may be the important factor for consistent winter survival under prairie conditions. A simple scoring system was developed to predict survival of strawberry plants. Key words. Fragaria × ananassa Duch., strawberry, crowns, low temperature hardiness

2010 ◽  
Vol 19 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Waldemar Żukowski ◽  
Agnieszka Bogdanowicz ◽  
Marlena Lembicz

Seed germination in sedges: a short reviewFive patterns of seed germination in the sedges of the genusCarexare presented, based on the literature data and the results of the authors' own research. They include the pattern ofC. acutiformis, C. arenaria, C. remota, C. flavaandC. communis. These patterns were constructed on the basis of seed specific requirements for development, such as stratification, temperature, dormancy and time of germination. Majority of sedges follow the pattern ofC. acutiformisorC. remota. In both cases, stratification and either high or low temperature are essential for seed germination. Seeds that start to germinate early (C. remotapattern) are characterized by the absence of the distinct peaks of germination, as opposed to theC. acutiformispattern with the germination peak in March. Our long-term investigations, conducted on the group of individuals in controlled conditions, revealed significant differences in seed size and the ability of seeds to germinate depending on the age of mother plants. We postulate that mother plant age is a new factor that should be considered in the construction of seed germination patterns.


1989 ◽  
Vol 69 (3) ◽  
pp. 711-714 ◽  
Author(s):  
K. I. N. JENSEN ◽  
E. R. KIMBALL ◽  
J. A. IVANY

The half-life of metribuzin applied to a bare soil surface was calculated to be 3–7 d over four field tests. An artificial cover erected after application or a shallow incorporation increased the half-life of metribuzin approximately 2.5- to 3-fold. Leaching out of the 0- to 5-cm-deep sampling zone could not account for loss of metribuzin. It was concluded that metribuzin persistence may be affected by volatility and/or photodecomposition losses under field conditions, especially shortly after application. Key words: Metribuzin half-life, volatility, photodecomposition, row width


2013 ◽  
Vol 320 ◽  
pp. 505-511
Author(s):  
Ning Li ◽  
Zhi Kai Wu ◽  
Chao Jian ◽  
Wan Qian Zhao ◽  
Jia Zhen Yan

During the 20th century, both dental materials and dental technologies for the fabrication of dental prosthesis progressed remarkably. Owing to the increased demand of safety and aesthetics, 3 mol% yttria stabilized tetragonal zirconia polycrystalline has been recently introduced in prosthetic dentistry for the fabrication of crowns and fixed partial dentures, in combination with CAD/CAM technique. This greatly changed the conventional dental laboratory work which is labor-intensive and experience-dependent. This review mainly introduced the state of dental zirconia and the application of CAD/CAM technology in dentistry. Key words: Dental Zirconia; CAD/CAM Technique; Mechanical Properties; Transformation Toughing; Low Temperature Aging;


Author(s):  
Andrey D. PLOTNIKOV ◽  
Aleksandr V. VODOLAZHSKIY ◽  
Natalya S. YAKUPOVA

The paper represents requirements for cryogenic grease lubricants used in the rocket and space technology. Data on lubricants based on perfluoropolyether liquid FEN is provided. New lubricant testing methods enabling to analyze their chemical composition and low-temperature characteristics are proposed. Quoted are investigation results for the equivalents of previously used cryogenic lubricants NIKA, NIRA and «Ametist». A practical relevance of the paper has been proven by introduction of low-temperature lubricants «Sever» currently being used in rocket and space items, as well аs successful application of the developed lubricant incoming inspection procedures at RSC Energia. Key words: low-temperature lubricant, perfluoropolyether liquid FEN, viscosity, solidification temperature, IR spectrum, potential evaporation.


Agronomy ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 59 ◽  
Author(s):  
Chen Liu ◽  
Ziwei Guo ◽  
Yoo Park ◽  
Hao Wei ◽  
Byoung Jeong

Vegetative propagation using runner plants is an important method to expand the cultivation area for the strawberry (Fragaria × ananassa Duch.). However, excessively long runners need an increased total amount of nutrients and energy to receive elongation from mother plants, which may lead to poor growth or reduced output. The use of plant growth regulators (PGRs) is an adoptable way to solve such problems. The objectives of this experiment were to study the effects of PGRs and their application methods on the growth and development of runners, runner plants, and mother plants, and also to find effective ways to control the number and length of runners without harmful side effects. Chlormequat chloride (CCC), 6-benzylaminopurine (BA), and ethephon (ETH) at a concentration of 100 mg·L−1 were applied via three different methods: injection into crowns, medium drench, and foliar spray. The results showed that BA injection into crowns was the most effective combination among all treatments, which prominently shortened the length of runners and increased the number of runners and leaves on a single plant. Furthermore, plants with BA solution injection tended to produce stronger runners with higher fresh and dry weights, without affecting the health states of mother plants. The ETH solution seemed to have toxic effects on plants, by leading many dead leaves and weak runners, and increased activities of antioxidant enzymes. Other than the injection method, the other two application methods of the CCC solution did not significantly affect the growth and development of both cultivars. Runner plants grown for 30 days were not affected by any treatments, and they were in similar conditions. Overall, BA injection into crowns is recommended for controlling the number and length of strawberry runners.


1988 ◽  
Vol 66 (7) ◽  
pp. 1381-1390 ◽  
Author(s):  
J. Escarré ◽  
C. Houssard

Germination of Rumex acetosella L. was studied under a variety of experimental conditions to determine whether populations from old fields of different ages (fallow for 6 months to 15 years) differed in seed weight and germination rate and in plant biomass and flowering rate of the resulting plants. Fresh seeds collected from these natural populations showed differences in germination that varied with the date of harvest and the number of years since the field was last cultivated: seeds of the youngest population harvested in July germinated the best and were lighter than those of the other populations. Different fertilizer levels applied during the growth of the mother plants from seeds collected in the original old fields affected the mean weight and the germination rate of the resulting seeds, regardless of the density of cultivation of the mother plant. However, the effect of different fertilizer levels on mean seed weight varied with the origin of each population. Heavy seeds (mean weight > 0.6 mg) of mother plants from the populations of fields abandoned over 2 years ago germinated better than light seeds (mean weight < 0.6 mg). There was no significant difference between heavy and light seeds in terms of percent germination for seeds from mother plants that came from the "youngest" field. These differences in germination rate observed in field-collected seeds were also found in light seeds of the offspring generation: light seeds of the mother plant from the population belonging to the more recently abandoned old field germinated the best. Plants grown from heavy seeds that came from the other populations of older fields had more biomass than those resulting from light seeds. This difference has not been observed between individuals resulting from light and heavy seeds of the youngest population. On the other hand, these individuals had a higher flowering rate than those resulting from the older populations. These results are interpreted in relation to the successional status of the populations: high flowering and early germination rates are suitable characteristics for establishment of plants on bare ground or after a disturbance, whereas heavy seeds with more reserves ensure germination and enough biomass of the resulting plants in density-dependent conditions.


1998 ◽  
Vol 76 (2) ◽  
pp. 213-220
Author(s):  
Mitchell D Refvik ◽  
Adrian L Schwan

Lithium (E)-1-hexenesulfenate (5a) was treated with a number of TMS-X (TMS = trimethylsilyl) reagents to afford N,N-bis(trimethylsilyl)-(E)-1-hexenesulfenamide (7a) and (or) di((E)-1 hexenyl) disulfide (8), usually in low yield. The cleanest reactions, those from use of TMS-Cl (to afford 7a) and TMS-CN (which yields 8) were analyzed by variable temperature NMR. It was found that the low-temperature silylation reaction using TMS-Cl affords 7a and thiosulfinate 12 as initial products. Warming the mixture coerces the decomposition of 12. Treatment of 5a with TMS-CN also yields thiosulfinate 12 which is reduced to disulfide 8 as the temperature warms, possibly by action of cyanide ion. Evidence is presented that allows a confident structural assignment of the transient thiosulfinate 12, and mechanisms are suggested for the formation of 12. The study also led to the NMR observation of (E)-1-hexenesulfenate (5a).Key words: sulfenate, thiosulfinate, variable temperature NMR (VT NMR), silylation.


1982 ◽  
Vol 62 (3) ◽  
pp. 679-687 ◽  
Author(s):  
J. N. B. SHRESTHA ◽  
L. AINSWORTH ◽  
D. P. HEANEY ◽  
A. N. SMITH

A 3-yr study demonstrates that commercially acceptable reproductive performance can be achieved in breeding sheep following the application of a fluorogestone-acetate- (FGA-) impregnated intravaginal sponge and pregnant mare's serum gonadotrophin (PMSG) treatment to induce a synchronized estrus under field conditions. Overall fertility, prolificacy and fecundity levels of 76%, 1.92 and 148%, respectively, resulted from breeding at the synchronized estrus, and 94%, 1.86 and 175%, respectively, due to breeding at the synchronized and subsequent estruses in the breeding (fall) season. In the nonbreeding (spring) season, these responses were 51%, 1.73 and 88%, respectively, at the synchronized estrus, and 63%, 1.61 and 109%, respectively, due to breeding at the synchronized and subsequent estruses. Significant farm-to-farm variation was observed with reproductive performance ranging from 77 to 100% for fertility, 1.45 to 2.74 for prolificacy, and 134 to 274% for fecundity in the estrous season. There were no significant differences among farms after synchronization and breeding during the anestrous season. Key words: Sheep, synchronization, fluorogestone acetate, pregnant mare's serum gonadotrophin, season, farm flocks.


2006 ◽  
Vol 86 (2) ◽  
pp. 221-224 ◽  
Author(s):  
H. J. Swatland

Beef rib roasts and steaks have a thick connective tissue aponeurosis which is often difficult to gelatinise by cooking. When heated in a water-bath, aponeurosis first increased in reflectance (maximum 0.026 ± 0.021 at 67.1 ± 5.5°C) before decreasing in reflectance as gelatinisation occurred. Contraction reached a maximum of 33.8 ± 15.8% of starting length at 69.2 ± 3.2°C and corresponded to the increase not the decrease in reflectance. Either contraction or increased reflectance might be used to select animals with low-temperature gelatinisation. Key words: Beef toughness, aponeurosis, cooking


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