Effect of paclobutrazol on flower-bud production and vegetative growth in two species of Eucalyptus

1993 ◽  
Vol 23 (4) ◽  
pp. 640-647 ◽  
Author(s):  
A.R. Griffin ◽  
P. Whiteman ◽  
T. Rudge ◽  
I.P. Burgess ◽  
M. Moncur

A series of experiments on field-grown seed-derived trees between 2 and 17 years old demonstrated that the growth regulator paclobutrazol could be used to reduce vegetative growth and enhance flower-bud production in Eucalyptusglobulus Labill. and Eucalyptusnitens (Dean & Maid.) ex Maid. Responses to high levels of trunk injection and collar drenching persisted for up to six growing seasons, yielding both increases in frequency of flowering and heaviness of bud crop. Growth responses were expressed in the immediate growing season, but flowering responses were not evident for another year. Foliar spray treatments reduced vegetative growth in young trees of both species for one growing season, but only the E. globulus showed an associated flowering response. Assessment of seed yield per capsule and subsequent germination tests showed no deleterious effects on seed development or quality. Choice of application method will vary with objective and size of tree. Collar drenching shows the most promise for treating large numbers of seed orchard trees because application time is substantially independent of tree size and weather conditions.

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 943
Author(s):  
Katri Nissinen ◽  
Virpi Virjamo ◽  
Antti Kilpeläinen ◽  
Veli-Pekka Ikonen ◽  
Laura Pikkarainen ◽  
...  

We studied the growth responses of boreal Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and silver birch (Betula pendula Roth) seedlings to simulated climate warming of an average of 1.3 °C over the growing season in a controlled field experiment in central Finland. We had six replicate plots for elevated and ambient temperature for each tree species. The warming treatment lasted for the conifers for three growing seasons and for the birch two growing seasons. We measured the height and diameter growth of all the seedlings weekly during the growing season. The shoot and root biomass and their ratios were measured annually in one-third of seedlings harvested from each plot in autumn. After two growing seasons, the height, diameter and shoot biomass were 45%, 19% and 41% larger in silver birch seedlings under the warming treatment, but the root biomass was clearly less affected. After three growing seasons, the height, diameter, shoot and root biomass were under a warming treatment 39, 47, 189 and 113% greater in Scots pine, but the root:shoot ratio 29% lower, respectively. The corresponding responses of Norway spruce to warming were clearly smaller (e.g., shoot biomass 46% higher under a warming treatment). As a comparison, the relative response of height growth in silver birch was after two growing seasons equal to that measured in Scots pine after three growing seasons. Based on our findings, especially silver birch seedlings, but also Scots pine seedlings benefitted from warming, which should be taken into account in forest regeneration in the future.


2014 ◽  
Vol 60 (No. 5) ◽  
pp. 234-240 ◽  
Author(s):  
D. Kviklys ◽  
M. Liaudanskas ◽  
V. Janulis ◽  
P. Viškelis ◽  
M. Rubinskienė ◽  
...  

The effect of weather conditions and eleven apple rootstocks was studied on the phenol content in fruits. Super-dwarf rootstocks P 61 and P 22 determined the highest content of all phenolic compounds tested. Dwarf rootstocks M.9, P 62 and semi-dwarf M.26 determined lower content of all phenolic compounds tested. The content of (+)-catechin, procyanidin B1 and total procyanidins content in apple fruits depended on rootstock genotype and high variation coefficient of these compounds between rootstocks was established. Rootstocks had a lesser effect on the content of quercitrin, (–)-epicatechin, total catechins, phloridzin and chlorogenic acid. No clear differences were found between super-dwarf, dwarf and semi-dwarf rootstock groups. Conditions during the growing season, yield and fruit weight impacted on the content of bioactive compounds. Less than 10% difference in total phenols between the growing seasons was recorded for M.26 and P 22. The greatest differences were recorded in the fruits from trees grown on M.9, Pure 1 and P 66 rootstocks. Rootstock B.396 determined the most stable content of all compounds analysed, except for procyanidin B1 and B2.


1992 ◽  
Vol 2 (4) ◽  
pp. 465-468 ◽  
Author(s):  
Gary J. Keever ◽  
Mark S. West

Uniconazole was applied once as a soil drench (15, 30, or 45 mg a.i./plant) or foliar spray (500, 1000, or 1500 mg liter-1, about 175 ml/plant) to established, field-grown thorny elaeagnus (Elaeagnus pungens Thunb. Fruitlandii) and leyland cypress [× Cupressocyparis leylandii (A.B. Jacks. & Dallim.) Dallim. & A.B. Jacks]. At the end of the second growing season following treatment, shoot dry weights (SDW) of thorny elaeagnus decreased with increasing rates of drench-applied uniconazole, while SDW of plants receiving the foliar application were not affected by increasing rates. Growth indices of leyland cypress, determined twice during the first growing season and at the end of the second growing season, were not influenced by application method or rate. Uniconazole applied as a soil drench at 15 to 45 mg a.i./plant suppressed growth of established thorny elaeagnus for at least two growing seasons, but leyland cypress was not affected by uniconazole drench or foliar spray at tested rates. No phytotoxicity was observed on either species in any treatment during the experiment.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yuta Kobayashi ◽  
Tetsunan Yamamoto ◽  
Hironori Ikeda ◽  
Ryuzo Sugihara ◽  
Hiroki Kaihori ◽  
...  

AbstractExcess water in vineyard soils during grapevine growing season is expected to become a critical issue in Japan. The objective of this study was to investigate the effects of constantly high soil water content which was controlled at constantly more than 20% water content in soil on vegetative growth and berry quality of Cabernet Sauvignon over a 3-year growing season. A wireless sensor networking system for real-time monitoring of soil moisture was used to check that the experimental plot had constantly more than 20% water content in soil. Véraison in the experimental plot controlled at constantly high soil water content started 10 days, 4 days and 1 day later than that in the non-irrigated experimental plot in the 2017, 2018 and 2019 growing seasons, respectively. The constantly high soil water content had no notable effects on berry quality, such as berry characteristics and berry composition, at harvest compared with the non-irrigated experimental plot, although there was a certain tendency that constantly high soil water content decreased anthocyanin contents in berry skins compared with those of non-irrigated grapevines during the three growing seasons. We postulated that waterlogging damage due to the increase in soil water content by frequent rainfall would be minimised by the selection of rootstock that confers tolerance to waterlogging stress for scion cultivars and/or viticultural practices to prevent decrease in soil temperature. Also, the introduction of Internet of Things technology for monitoring water status in vineyard soil is expected to contribute to improving practical approaches to vineyard soil water management.


2002 ◽  
Vol 82 (4) ◽  
pp. 755-763 ◽  
Author(s):  
J. M. Caprio ◽  
H. A. Quamme

An iterative χ2 method applied to 60 yr of records in the Okanagan Valley of British Columbia (1930–1989) revealed that the main climatic factor limiting grape production (Vitis spp. and Vitis vinifera L.) was low temperatures (critical value range, ≤–6°C to ≤–23°C) occurring during late October, November, December and February. Daytime temperatures ≤–9°C during late November and early December benefited grape production, probably because it prevented vine de-acclimation. Detrimental effects of precipitation during late October were probably associated with the early movement of Arctic fronts into the region. Beneficial effects of precipitation in the form of snow were observed in January. During the pre-harvest growing season, except for a 2-wk period in July, high temperatures (≥26°C) were associated with good production, probably because warm temperatures are required for flower bud initiation and development. In contrast, higher-than-normal temperatures were not beneficial to production during the harvest year. Detrimental effects of high temperature were observed during July of the pre-harvest year and July (≥32°C) and early August of the harvest year (≥28°C). During the growing season, rainfall was sometimes unfavourable for grape production under irrigation, either because of associated cool weather or greater disease occurrence. Both temperature and precipitation were greater in the last 18 yr of the study than the prior 36 yr, especially during the late winter and early spring. The anticipated climatic change appears to favour grape production in the Okanagan Valley. Key words: grape, climate change, heat stress, winter injury


2016 ◽  
Vol 130 (1) ◽  
pp. 56 ◽  
Author(s):  
Zoe A. Panchen

To maximise reproductive success in the short Arctic growing season, plants pre-form flower buds the year prior to flowering. Flower bud production depends on warm ambient temperatures. Thus, although currently Arctic plants have low rates of sexual reproductive success, the warming climate may increase reproductive success. Following the long, warm growing season in 2012, plants at Lake Hazen, Ellesmere Island, produced many flowers in the short, cold growing season of 2013. Conversely, few flowers were produced in 2014, a long, warm growing season, but many flowers were produced in 2015, another long, warm growing season. Potentially higher rates of reproductive success in a warming climate could be compromised if consecutive years do not have long, warm growing seasons.


2012 ◽  
Vol 62 (4) ◽  
pp. 451-462 ◽  
Author(s):  
Małgorzata Proćków ◽  
Elżbieta Kuźnik-Kowalska ◽  
Małgorzata Lewandowska

Population dynamics of a meso-hygrophilous helicoid Bradybaena fruticum was studied in SW Poland at two localities with similar habitat but different climatic conditions. Unexpectedly, at the submontane site in Szczytna the growth appeared to be significantly faster than in the lowland site (Wrocław), where the weather conditions varied widely during the whole growing season. In Szczytna the average growth rate was 0.26 whorl/month; 0.36 whorl/month in the fast phase (juveniles from hatching till 5.0 whorls), and 0.07 whorl/month in the slow phase (snails with 5.1 whorls till lip formation). During the whole growing season, the average increment was 4.5 whorls, whereas the maximum was 5.45 whorls. In Wrocław the average growth rate was 0.05 whorl/month; 0.1 whorl/month in the fast phase, and only 0.01 whorl/month in the slow phase. The average growth of juveniles, estimated during two growing seasons, equalled 3.8 whorls; the maximum recorded value was 4.75 whorls. In the winter there was hardly any growth. In earlier studies it was found that at higher altitude the growth rate seems to decrease and therefore appears to be correlated with the thermal regime of the locality. In this study it was established that the weather patterns, like months with drought or occasional flooding, are likely to influence the population dynamics in the lowland population.


2016 ◽  
pp. 41-46
Author(s):  
Vlado Kovacevic ◽  
Jasna Sostaric

Main field crops in Croatia are maize, soybean, sunflower and sugar beet. By these crops are covered (status 2014) close to 50% (385 234 ha) of utilized arable land. Global warming, have often adverse influence on field crop yields. Aim of this study was testing precipitation and temperature regimes on spring crops yield in Croatia in 15-year period (1999–2013) and elaboration of the 2014 growing season with aspect of climatic change. Four growing seasons (2000, 2003, 2007 and 2012) were less favorable for maize because annual yield was bellow 5 t ha-1 (average 4.38 t ha-1), while in four more favorable years (2005, 2008, 2009 and 2010) annual yield was above 6.8 t ha-1 (average 7.32 t ha-1). Average precipitation and temperature for the April-September period in Osijek were 226 mm and 496 mm, 19.6 oC and 18.6 oC, for less and more favorable years, respectively. Yields of soybeans and sugar beet have mainly similar trend as maize yields in function of weather conditions, while sunflower is more susceptible to extremely moist growing seasons (for example, 2001 and 2005: 650 mm and 697 mm precipitation and very low yields in level 1.7 and 1.6 t ha-1, respectively). On the other side, under drought conditions of 2003, 2007 and 2012, yields of sunflower were above average in range from 2.5 to 2.7 t ha-1), while at same period yields of maize, soybean and sugar beet were drastically reduced. Average precipitation in the April-September period of 2014 for eight selected sites of Croatia was 756 mm or for 68% higher in comparison with the long-term average 1961–1990 with variation among the sites from 520 mm in Osijek to 910 mm in Varazdin. On the other side, average air-temperature in 2014 was 17.8 oC or for 0.7 oC higher with variations among the sites from 17.2 oC in Daruvar and Varazdin to 18.2 oC in Osijek and 18.3 oC in Gradiste. Under these favorable weather conditions, annual yields of maize (8.1 t ha-1), soybeans (2.8 t ha-1) , sunflower (2.9 t ha-1) and sugar beet 63.6 t ha-1) were considerable higher than usual.


HortScience ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 558-561 ◽  
Author(s):  
Anita Solar ◽  
Jerneja Jakopič ◽  
Robert Veberič ◽  
Franci Štampar

Prohexadione-calcium (ProCa), formulated as Regalis, was tested as a vegetative growth inhibitor in rejuvenated annual shoots of 14-year-old mother trees in the ‘Franquette’ walnut cultivar. ProCa was applied three times during growing seasons in 2005 (Y5) and 2006 (Y6). This was during the second half of spring growth flush, the resting phase between the first and second growth flushes, and in the middle of summer growth flush. As a result, treated shoots in the upper part of the canopy were shorter than untreated ones during the whole growing season in both years. In Y5, two treatments of ProCa (250 mg·L−1), applied until the middle of June, inhibited shoot elongation during summer growth, which was the main purpose of the experiment. The reduction of shoot elongation was between 18% [lower shoots in the canopy (LS)] and 33% [upper shoots (US)]. After three ProCa applications, also the final length of the shoots was reduced by 5% (US) and 18% (LS). In Y6, when 100 mg·L−1 of ProCa had been used, strong reduction (24%) was observed only in US after two treatments. Summer growth was not reduced, probably as a result of an interaction between lower concentration of ProCa and stress caused by a water deficit and extremely high temperatures during the summer. On the base of the shoots, three treatments of ProCa (100 mg·L−1) in Y6 increased the ratio between wood and pith and, consequently, increased the quality and uniformity of the scion wood. Further research into additional cultivars and ProCa concentrations is recommended to optimize the terms of application.


2014 ◽  
Vol 28 (2) ◽  
pp. 239-249 ◽  
Author(s):  
Klára Taufarová ◽  
Kateřina Havránková ◽  
Alice Dvorská ◽  
Marian Pavelka ◽  
Marek Urbaniak ◽  
...  

Abstract Net ecosystem production reflects the potential of the ecosystem to sequestrate atmospheric CO2. Daily net ecosystem production of a mountain Norway spruce forest of the temperate zone (Czech Republic) was determined using the eddy covariance method. Growing season days when the ecosystem was a CO2 source were examined with respect to current weather conditions. During the 2005, 2006, and 2007 growing seasons, there were 44, 65, and 39 days, respectively, when the forest was a net CO2 source. The current weather conditions associated with CO2 release during the growing seasons were: cool and overcast conditions at the beginning or end of the growing seasons characterized by a 3-year mean net ecosystem production of -7.2 kg C ha-1 day-1; overcast or/and rainy days (-23.1 kg C ha-1 day-1); partly cloudy and hot days (-11.8 kg C ha-1 day-1); and overcast and hot days (-13.5 kg C ha-1 day-1). CO2 release was the highest during the overcast or/and rainy conditions (84%, average from all years), which had the greatest impact during the major production periods. As forests are important CO2 sinks and more frequent weather extremes are expected due to climate change, it is important to predict future forest carbon balances to study the influence of heightened variability in climatic variables.


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