Hoffmann, Richárd

Kazinczi, Gabriella

Kerepesi, Ildikó

Pál-Fám, Ferenc

English

JKI Open Journal Systems (Julius Kühn-Institut)

Julius-Kühn-Archiv 455 | 2016HALT Ambrosia - final project report and general publication of project findings21HALT Ambrosia - final project report and general publication of project findingsEffect of emergence time on life cycle, shoot dry weight, pollen and seed productionGabriella Kazinczi, Ferenc Pál-Fám, Richárd Hoffmann, Ildikó KerepesiDepartment of Plant Production and Plant Protection, Institute of Plant Science, Faculty of Agricultural and Environmental Sciences, Kaposvár University, Guba S. str. 40, H-7400 Kaposvár, Hungary;  e-mail: kazinczi.gabriella@ke.huDOI 10.5073/jka.2016.455.07In another experiment emerged common ragweed seedlings within the same observation period (every ten days) were signed similarly in the experimental area. In order to get informations about the real biological potential of common ragweed inter- and intraspecific competition was excluded by continuous hand weeding during the experimental period (from March until November). Emergence time obviously had some influence on final shoot dry weight, measured at the end of the vegetation period (November 2011, Table. 1).When seeds emerged later, shoot dry weight of A. artemisiifolia plants considerably reduced.Table. 1: Final shoot dry weight (means and standard deviation in g/individual) of common ragweed depending on the emergence time (months/decades e.g. 4/1: first decade of April)Emergence time4/1 4/2 4/3 5/1 5/2 5/3 6/1 6/2 6/3 7/1 7/2 7/3Shoot dry weight (g/plant)1840±6091682±3631284±422972±3491436±3541487±416914±0349±130404±246- - 26±15Emergence time obviously also has serious influence on pollen production (number of male heads/plant: considering a mean of 17 male flowers per head and of 7148 pollen/male flower; see Reisinger and Szemenyei (2006), Table. 2, and on seed production (number of seeds per individual, Table 3). The later common ragweed germinated the quicker the individuals developed from seedling to flowering plants. Even common ragweed plants that emerged by end of July produced seeds until end of September (Table 4).Table. 2: Number of male heads per individual of common ragweed depending on the emergence time (months/decades); average estimated pollen number per individual in greenEmergence time4/1 4/2 4/3 5/1 5/2 5/3 6/1 6/2 6/3 7/1 7/2 7/3Number of male capitula/plant137531±88873over 16 milliard pollen125910±58151107435±9608742827±1523057071±3335994155±5816927552±027372±1384111994±187- - 817±340~0.1 mil-liard pollenJulius-Kühn-Archiv 455 | 201622HALT Ambrosia - final project report and general publication of project findingsHALT Ambrosia - final project report and general publication of project findingsTable 3: Total number of seeds (min-max in black; means in red) and number of viable seeds (green) per individual of common ragweed depending on the emergence time (months/decades)Emergence time4/1 4/2 4/3 5/1 5/2 5/3 6/1 6/2 6/3 7/1 7/2 7/3Seed number for a plant1 7 7 7 8 -74125av.33230116305 0 0 0 -94900av.46185429522 1 2 5 -50500av.26118161938 5 0 -58493av.170591364716830-53625av.326301696719300-48200av.371002522848375av.48375445051 0 2 7 5 -33857av.25272229987 9 2 1 -31938av.1950218527- - 225-1700av.1144708Table 4: Changes in phenological stages of common ragweed plants that emerged at different times; date of emergence and measurement in decades of months; developmental stages following the BBCH-scale (Hess et al., 1997; Meier, 2001).Observation time Emergence time4/1 4/2 4/3 5/1 5/2 5/3 6/1 6/2 6/3 7/34/1 094/3 12-14 14-16 095/2 22 19 16 12-14 09-126/1 32-39 26-35 16-26 20-22 18-19 16-18 106/3 51-55 49-51 39-51 39-51 26-39 26-30 18 14-16 09-127/2 65-69 49-61 49-61 49-51 49-51 45-48 39 26-32 19-228/1 65-70 51-65 51-65 52-55 51-55 51-55 51 32-39 32-39 09-128/3 69-79 68-70 66-69 68-78 68-69 68-78 69 68-69 68-69 32-519/2 79-81 71-75 69-71 71-78 71-78 78-81 75 69-75 75-79 71-7810/1 81-88 81-85 81-85 81-87 81-87 81-85 85 81-85 81-87 78-8110/3 97 97 97 97 97 97 97 97 97 97It is concluded that data of biomass production (including, shoot dry weight, pollen- and seed pro-duction for an individual plant) considerably varied between individuals (high values of standard deviations!) even inside the same emergence period. This suggests that emergence time is only one factor determining biomass (shoot dry weight, pollen, seed) production of common ragweed (Hoffmann et al., 2010).Emergence time greatly influenced seed viability, but – irrespectively to emergence time – autumn collected common ragweed seed samples (stored in paper bags at room temperature  for a half year) were in strong dormancy in spring of next year (germination percentages (4-29%) were far below to those of viability (35-95%) (Figure 1).Julius-Kühn-Archiv 455 | 2016HALT Ambrosia - final project report and general publication of project findings23HALT Ambrosia - final project report and general publication of project findingsFigure. 1: Germination and viability of common ragweed seeds (KU-HU 2012).ReferencesHess, M., Barralis, G., Bleiholder, H., Buhr, L., Eggers, T., Hack, H., Stauss, R. (1997): Use of extended BBCH scale - General for descriptions of growth stages of mono- and dicotyledonous weed species. Weed Research 37: 433-441Hoffmann, R., Béres, I., Máté, S., Pál-Fám, F., Csöndes, I., Kazinczi, G. (2010): Field emergence and biomass production of Ambrosia artemisiifolia L. (common ragweed). 15th EWRS Symposium, Kaposvár, Hungary p.208.Meier, U. (2001): Growth stages of mono-and dicotyledonous plants. Federal Biological Research Centre for Agriculture and Forestry, Berlin.Reisinger, P. and  Szemenyei  Sz. (2006): Pollenszám vizsgálatok eredményei Ambrosia artemisiifolia növényen. 27. Integrált termesztés a kertészeti és a szántóföldi kultúrákban. Növény-és Talajvédelmi Központi Szolgálat Kiadványa, Budapest pp.102-110. (in Hungarian).01020304050607080901001Apr 2Apr 3Apr 1May 2May 3May 1JUne 2June 3June 3Julyemergence timegermination (%)seed viability (%)

Effect of emergence time on life cycle, shoot dry weight, pollen and seed production

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Effect of emergence time on life cycle, shoot dry weight, pollen and seed production

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