Seed characteristics and nursery production of several species from the genus Sorbus L.

Rod Sorbus L. pripada porodici Rosaceae, potporodici Pomoideae te obuhvaća 80-100 vrsta listopadnog drveća i grmlja rasprostranjenog na Sjevernoj hemisferi. Zbog mesnatih plodova u kojima se nalazi sjeme, vrste roda Sorbus L. spadaju u šumsko voće gdje pripadaju i druge sporedne vrste drveća koje doprinose biološkoj raznolikosti sastojina, služe kao potpora glavnim vrstama drveća i poboljšavaju kvalitetu tla. Sve vrste roda Sorbus L. u Republici Hrvatskoj, kao i u većini europskih zemalja, su rijetke i ugrožene. Cilj ovih istraživanja je odrediti brojne značajke sjemena četiri vrste roda Sorbus L., odnosno ispitati različite metode i tehnologije proizvodnje sadnica u rasadniku. Tijekom jeseni 2003. godine na različitim lokalitetima u Republici Hrvatskoj pronađena su i izmjerena stabla četiri vrste roda Sorbus (Sorbus aria, Sorbus aucuparia, Sorbus domestica i Sorbus torminalis). Ukupno je registrirano 77 stabala, od toga 13 stabala mukinje, 14 stabala jarebike, 13 stabala oskoruše i 37 stabala brekinje. Tijekom jeseni 2003-2008. godine na stablima se procjenjivao stupanj uroda i sakupljali su se plodovi. Na plodovima i sjemenu obavljena su morfometrijska mjerenja i vaganja. Elementi kvalitete sjemena određeni su u skladu sa pravilima ISTA. Sadnice su se proizvodile u rasadniku tijekom pet kontinuiranih godina istraživanja (2004-2008). Dobar urod stabala mukinje (Sorbus aria L.), oskoruše (Sorbus domestica L.) i brekinje (Sorbus torminalis (L.) Crantz) u Republici Hrvatskoj događa se intervalima od svake četiri godine odnosno stabala jarebike (Sorbus aucuparia L.) u intervalima od svake tri godine. Prosječan broj punih sjemenki u plodu (2003-2007) jarebike i oskoruše iznosio je 1,9, u plodu mukinje 1,1 odnosno u plodu brekinje 0,9 komada. Najveći broj sjemenki u plodu mukinje dobiven je u godinama najboljeg uroda. Prosječna težina ploda (2003-2007) oskoruše iznosila je 8,82 g, brekinje 1,08 g, mukinje 1,05 g odnosno jarebike 0,47 g. Plodovi brekinje imali su prosječno najveću težinu u godinama dobrog uroda. Prosječna apsolutna težina sjemena (2003-2007) oskoruše iznosila je 27,99 g, brekinje 25,74 g, mukinje 16,91 g odnosno jarebike 3,95 g. Korelacija između stupnja uroda i apsolutne težine sjemena oskoruše je pozitivna i značajna. Izolirano stablo brekinje (Korenica), imalo je prosječno najmanju aspolutnu težinu sjemena (2003-2007). Dobivena je pozitivna i visoka korelacija između mase ploda i mase sjemena u plodu mukinje, oskoruše i brekinje. Dobivena je pozitivna i visoka korelacija između mase ploda i broja punih sjemenki u plodu jarebike i oskoruše. Na masu sjemena u ukupnoj masi ploda otpada prosječno kod mukinje 5,58%, kod jarebike 3,92%, kod oskoruše 1,11% odnosno kod brekinje 4,52%. Prosječno najveći vitalitet, za sve godine istraživanja i sve lokalitete, imalo je sjeme oskoruše (89,3%), slijedi vitalitet sjemena jarebike (84,5%), brekinje (83,5%) i mukinje (68,0%). Za savladavanje dvostruke dormantnosti sjemena sve četiri istraživane vrste roda Sorbus L. sa područja Republike Hrvatske, mogu se primjeniti uvjeti i trajanje stratifikacije navedeni u pravilima ISTA. Prosječna klijavost (2003-2008) na kraju razdoblja stratifikacije iznosila je kod sjemena mukinje 11,5%, kod sjemena jarebike 3,9%, kod sjemena oskoruše 22,5% odnosno kod sjemena brekinje 36,7%. Prosječno najveću laboratorijsku klijavost (2003, 2004, 2007), u skladu sa pravilima ISTA, imalo je sjeme oskoruše (71,3%) slijedi laboratorijska klijavost sjemena brekinje (64,9%), mukinje (53,2%) i jarebike (30,0%). Kod sve četiti vrste dobivene su pozitivne i vrlo visoke korelacije između energije klijavosti sjemena u laboratoriju i ukupne laboratorijske klijavosti. Prosječno najveću rasadničku klijavost (2003-2007) imalo je sjeme oskoruše (56,8%), slijedi rasadnička klijavost sjemena brekinje (40,5%), mukinje (27,3%) i jarebike (6,6%). Kod sve četiri istraživane vrste roda Sorbus L, dokazane su pozitivne i vrlo visoke korelacije između laboratorijske i rasadničke klijavosti sjemena. Prosječna visina sadnica mukinje 1+0 (2004, 2005, 2007, 2008) iznosila je 99 mm a promjer vrata korijena 5,22 mm. Prosječna visina sadnica mukinje 2+0 (urod 2003) iznosila je 437 mm a promjer vrata korijena 10,43 mm. Prosječna visina sadnica jarebike 1+0 (2004, 2005, 2006) iznosila je 313 mm a promjer vrata korijena 7,10 mm. Prosječna visina sadnica jarebike 2+0 iznosila je 744 mm a promjer vrata korijena 10,56 mm. Prosječna visina sadnica oskoruše 1+0 (2004, 2005, 2006, 2007, 2008) iznosila je 286 mm a promjer vrata korijena 5,34 mm. Prosječna visina sadnica oskoruše 2+0 (urod 2003) iznosila je 635 mm a promjer vrata korijena 8,48 mm. Prosječna visina sadnica brekinje 1+0 (2004, 2005, 2007, 2008) iznosila je 198 mm a promjer vrata korijena 6,00 mm. Prosječna visina sadnica brekinje 2+0 (urod 2003) iznosila je 442 mm a promjer vrata korijena 8,53 mm. Dokazana je pozitivna i dosta značajna korelacija između apsolutne težine sjemena brekinje i preživljavanja biljaka u rasadniku. Sadnice jarebike u rasadniku pokazuju najveću otpornost spram biotskih i abiotskih čimbenika, slijedi otpornost sadnica brekinje, oskoruše i mukinje. Na osnovu istraživanja visinskog rasta i prirasta sadnica brekinje u rasadniku, predlaže se uzgoj u sijalištu samo jednu vegetaciju (1+0), bez podrezivanja korjenskog sustava. Sadnice jarebike najbolje podnose presadnju u rasadniku i ne doživljavaju šok uslijed presadnje za razliku od sadnica oskoruše a pogotovo brekinje. Trogodišnje školovane sadnice mogu se koristiti za potrebe urbanog šumarstva ili kao podloge za cijepljenje raznih sorti i kultivara (kod oskoruše i jarebike). Analizom varijance nisu dobivene statistički značajne razlike u visinama odnosno promjeru vrata korijena sadnica mukinje, oskoruše i brekinje u ovisnosti o tri tipa BCC kontejnera (V-265, V-150 i V- 120 SS). Razmnožavanje zelenim reznicama u praksi bi se moglo preporučiti možda samo kod jarebike i njezinih kultivara dok ostale tri vrste nemaju visok postotak zakorjenjivanja ili se uopće ne mogu zakorjeniti tako da ova metoda ne može biti ekonomski isplativa.The Genus Sorbus L. belongs to the family Rosaceae, subfamily Pomoideae and encompasses 80-90 different species of deciduous trees and shrubs distributed in the northern hemisphere. Due to their fleshy fruits containing seeds, the Sorbus L. species belong to forest fruit, together with other weaker species which contribute to the biological diversity of stands, support the main tree species and improve soil quality. In Croatia, just as in most European countries, all the species from the genus Sorbus L. are rare and endangered. The aim of this research is to determine numerous seed characteristics of four species from the genus Sorbus L., i.e. to examine different methods and technologies for a nursery production of seedlings. In autumn 2003 trees from four species of the genus Sorbus L. (Sorbus aria, Sorbus aucuparia, Sorbus domestica and Sorbus torminalis) were chosen and measured at different sites in the Republic of Croatia. There was a total of 77 registered trees, of which 13 were Rowans, 14 Mountain Ashes, 13 Service and 37 Wild Service Trees. From autumn 2003 to autumn 2008 the yield grade was estimated, fruits were collected, and the fruits and seeds were morphometrically measured and weighed. The elements of seed quality were determined in line with the ISTA rules. Throughout the five consecutive years of the research (2004-2008) seedlings were produced in nurseries. In Croatia a good yield of Rowan (Sorbus aria L.), Service Tree (Sorbus domestica L.) and Wild Service Tree (Sorbus torminalis (L.) Crantz) occurs at four-year intervals while the Mountain Ash has a good yield every three years. The average number of filled (sound) seeds per one fruit of the Mountain Ash and Service Tree amounted to 1,9, of the Rowan 1,1 and of the Wild Service Tree 0,9. The largest number of seeds in a Rowan fruit was recorded in the years of its best yield. The average fruit weight (2003-2007) was 8,82 g for the Service Tree, 1,08 g for the Wild Service Tree, 1,05 g for the Rowan and 0,47 g for the Mountain Ash. The Wild Service Tree fruits reached their largest average weight in the years of good yields. An average absolute seed weight (2003-2007) was 27,99 g for the Service Tree, 25,74 g for the Wild Service Tree, 16,91 g for the Rowan and 3,95 g for the Mountain Ash. There is a positive and significant correlation between the yield grade and the absolute seed weight of the Service Tree. The lowest average absolute seed weight was obtained for an isolated Wild Service Tree (Korenica). A positive and a high correlation between fruit mass and seed mass was obtained for Rowan, Service Tree and Wild Service Tree fruits. The fruit mass and the number of filled (sound) seeds in the fruits of the Mountain Ash and Service Tree were also positively and highly correlated. The seed mass participated in the total fruit mass with 5,58% for the Rowan, 3,92% for the Mountain Ash, 1,11% for the Service Tree and 4,52% for the Wild Service Tree. The Service Tree seed had the best average vitality (89,3%) in all the research years, followed by the Mountain Ash (84,5%) and the Rowan (68,0%). The conditions and duration of stratification as determined by the ISTA rules can be applied for breaking the double seed dormancy of all the four researched species of the genus Sorbus L. At the end of the period of stratification the Rowan seeds reached an average germination (2003-2008) of 11,5%, the Mountain Ash seeds 3,9%, the Service Tree seeds 22,5% and the Wild Service Tree seeds 36,7%. The best laboratory germination (2003, 2004, 2007) in line with the ISTA rules was recorded for the Service Tree seeds (71,3%), followed by the Wild Service Tree (64,9%), the Rowan (52,3%) and the Mountain Ash (30,0%). A positive and a very high correlation between the seed germination energy in the laboratory and the total laboratory germination was established for all the four species. The best average nursery germination (2003-2007) was recorded for the Service Tree seed (56,8%), followed by the nursery germination of the Wild Service Tree (40,5%), the Rowan (27,3%) and the Mountain Ash (6,6%). A positive and a very high correlation between the laboratory and the nursery germination was confirmed for all the four species of the genus Sorbus L. The Rowan seedlings 1+0 (2004, 2005, 2007, 2008) had an average height of 99 mm and the root collar diameter of 5,22 mm. The average Rowan seedling height 2+0 (2003 yield) totalled 437 mm with the root collar diameter of 10,43 mm. The Mountain Ash seedlings 1+0 (2004, 2005, 2006) had an average height of 313 mm and the root collar diameter of 7,10 mm. The average height of the Mountain Ash seedlings 2+0 was 744 mm and the root collar diameter 10,56 mm. The Service Tree seedlings 1+0 (2004, 2005, 2006, 2007, 2008) had an average height of 286 mm and the root collar diameter of 5,34 mm. The average height of the Service Tree seedlings 2+0 (2003 yield) was 635 mm and the root collar diameter 8,48 mm. The Wild Service Tree seedlings 1+0 (2004, 2005, 2007, 2008) had an average height of 198 mm and the root collar diameter of 6,00 mm. The average height of the Wild Service Tree seedlings (2+0) (yield 2003) was 442 mm and the root collar diameter 8,53 mm. A positive and a significant correlation between the absolute seed weight and the nursery survival of the plants was confirmed for the Wild Service Tree seeds. In the nursery the Mountain Ash seedlings exhibited the best resistance to biotic and abiotic factors, followed by the Wild Service Tree, the Service Tree and the Rowan seedlings. On the basis of the research into the height growth and the increment of the Wild Service Tree seedlings, the production in sowing beds is recommended for only one vegetation (1+0), and without the root system pruning. Mountain Ash seedlings best tolerate when transplanted in a nursery where transplanting itself does not cause stress, unlike the Service Tree and especially the Wild Service Tree seedlings. Three-year old seedlings can be used in urban forestry or as rootstocks for grafting different sorts and cultivars (for the Service Tree and the Mountain Ash). The variance analysis did not reveal any statistically significant differences in heights and root collar diameter of the Rowan, the Service and the Wild Service Tree with respect to three types of BCC containers (V-265, V-150 and V-120 SS). The propagation with softwood cuttings could be recommended only for the Mountain Ash and its cultivars while for the other three species the rooting success is very poor or inexistent, due to which this method is not economically profitable

Eastern Alumnus Vol. 12 No. 1 (June 1958)

Cutlip, Barrick Receive Lord Scholarship Honors At Spring Commencement; Photographer Fred Ryan Retires After 34 Years And Some 100,000 Photos; etc.https://thekeep.eiu.edu/eiu_alumni_news_1958/1001/thumbnail.jp

Jestiva krizantema

Krizanteme su višenamjenske biljke, zbog lijepa cvijeta najviše se koriste kao ukrasne biljke, posađene u vrtu, kao rezano cvijeće ili kao lončanice. U Hrvatskoj se tradicionalno koriste kao cvijeće za kićenje grobova, najvjerojatnije zato što su to biljke kratkog dana koje cvjetaju uoči blagdana Svih svetih

Divovske bundeve

Bundeve (Cucurbita maxima) ubrajaju se u najstarije kultivirane biljke. One spadaju među najraznovrsnije među svim biljkama u prirodi. Zbog prilagodljivosti različitim uvjetima okoline, raširene su po cijelom svijetu, a raznolikost im omogućuje bezbroj načina upotrebe

Ciklanter – jestiv i dekorativan

Ciklanter (Cyclanthera pedata) u našem je podneblju sasvim nepoznata biljka iz porodice tikava (Cucurbitaceae). Riječ je o jednogodišnjoj biljci penjačici s vrlo dekorativnim i nazupčanim listovima stopalastog oblika sa 5 do 7 liski. Zbog brzog rasta i dekorativnosti može se koristiti kao ukrasna penjačica

Domaci ekološki insekticid

Među krizantemama svakako jedna od najkorisnijih je naša dalmatinska krizantema, buhač, buvač ili buharica od kojeg se dobiva najstariji i prvi poznati (ujedno i najjači) prirodni insekticid, piretrin

PROPAGATION OF PAULOWNIA BY ROOT CUTTINGS

U rod Paulownia, porodica Paulowniaceae, ubraja se od devet vrsta i nekoliko prirodnih hibrida koji od prirode rastu u Kini. Važne vrste u ovom rodu su: P. albiflora, P. australis, P. catalpifolia, P. elongata, P. fargesii, P. fortunei, P. kawakamii i P. tomentosa. U novije vrijeme hibridizacijom su dobiveni brojni hibridi s ciljem povećanja brzine rasta i prirasta te otpornosti na niske temperature. U Hrvatskoj se najčešće razmnožavaju hibridi paulovnije Shan Tong i 9501 iako postoje i drugi dobiveni vlastitim selekcijama. Cilj ovoga članka je objasniti načine razmnožavanja paulovnije u prirodi i problematiku njezine invazivnosti te razmnožavanje u rasadniku pomoću autovegetativne metode makropropagacije korjenovim reznicama. Postoje tri faze zakorjenjivanja reznica: inicijacija, indukcija i ekspresija. Postoji direktna i indirektna indukcija. Najosjetljiviji trenutak je povezivanje provodnih elemenata korjenčića i dijela stanice. Uspješnost pojave korjenčića na reznici ovisi o: fiziološkom stanju matične biljke, količini šećera, metabolizmu auxina, mineralnoj ishrani, metabolizmu fenola i dr. Postoje četiri faze razmnožavanja paulovnije iz korijenskih reznica: uzimanje i dorada korijenskih reznica s matične biljke u matičnjaku, pikiranje reznica u pvc lončiće ispunjene supstratom za zakorjenjivanje, zakorjenjivanje korjenskih reznica i osnivanje novog matičnjaka. Korijenske reznice paulovnije Shang Tong i 9501 uzimane su s obzirom na polaritet na način da se donji (distalni) dio korijena rezao pod kutom od 45 stupnjeva a gornji (proksimalni) pod kutom od 90 stupnjeva. Reznice su podijeljene su na kratke (8 cm) i dugačke (15 cm). Svaka skupina reznica dodatno je podijeljena na tanke i debele na način da razlika bude na oko vidljiva. Iz svake skupine u istraživanje je uzeto po 15 reznica. Napravljen je pokus na način da jedan dio reznica bude pikiran u grijanom stakleniku 7 dana od vađenja korijena a drugi dio nakon sušenja na sobnoj temperaturi u komori rasta. Prva skupina od 60 reznica uzeta je 14. prosinca i pikirana u perforirane pvc vrećice volumena 5,0 l i u gotovi supstrat za zakorjenjivanje Klasman Steckmedium. U supstrat za zakorijenjivanje dodano je 3g/l gnojiva s produženim djelovanjem treće generacije Osomocote Exact Standard 5-6M formulacije 15-9-12+2MgO+TE. Reznice nisu tretirane fitohormonom niti fungicidima protiv truleži. Pikiranje reznica je obavljeno na način da je gornja površina reza od 90 stupnjeva bila u razini supstrata. Duga skupina od 60 reznica stavljena je na sušenje u komoru rasta Kambič RK-980 CH. Temperatura u komori iznosila je 21 °C i relativna vlaga zraka od 40 % što predstavlja čuvanje reznica u konstantnim sobnim uvjetima. Reznice su čuvane u komori rasta 5 dana. Pikiranje je obavljeno na isti način kao i u slučaju prve skupine reznica 21.12.2017. godine. Prvo registriranje zakorjenjivanja obavljeno je 19.02.2018. godine što znači za prvu skupinu 67 dana od pikiranja a za drugu skupinu 60 dana od pikiranja. Sušenje reznica hibrida paulovnije Shan Tong dovelo do povećanja zakorjenjivanja u svim varijantama, a posebno je izraženo kod debelih reznica duljine 8 cm i debelih reznica duljine 15 cm. Može se preporučiti uzimanje debljih reznica i njihovo sušenje na sobnoj temperaturi u trajanju od 5 dana jer se dobiva značajnije veći postotak zakorjenjivanja. Pretjerana vlaga u supstratu za zakorjenjivanje korijenskim reznicama paulovnije negativno utječe na razvoj korijenskog sustava. Kod hibrida paulovnije 9501 također je utvrđeno kako sušenje reznica dovodi do povećanja zakorjenjivanja u svim varijantama, osim kod tankih reznica duljine 8 cm kod kojih je dobiven isti postotak zakorjenjivanja (33%). Posebno je zanimljiva situacija kod debelih reznica duljine 8 cm kod kojih se bez sušenja nije zakorjenila niti jedna reznica a sa sušenjem čak 80 %. Može se preporučiti uzimanje debljih reznica hibrida paulovnije 9501 i njihovo sušenje na sobnoj temperaturi u trajanju od 5 dana jer se dobiva značajnije veći postotak zakorjenjivanja. Postotak zakorjenjivanja reznica bez sušenja bio bi sigurno veći da su se uzele odmah nakon vađenja korijenskog sustava bagerom što se preporuča u praksi. U ovom slučaju minimalne temperature zraka od -4 °C i -5,6 °C dovele su do smrzavanja korijenskog sustava. Prosječna minimalna temperatura zraka u razdoblju od 8. do 14. prosinca. iznosila je svega 0,8 °C. Kod smrznutog korijena kora se odvaja rukom od drva a takve reznice ili propadaju ili tjeraju iz nižih adventivnih pupova. Korijenske reznice hibrida paulovnije Shan Tong i 9501 trebale bi se uzimati odmah nakon vađenja korijenskog sustava matične biljke a prosječne temperature zraka trebale bi biti iznad 0 °C. U ovim istraživanjima dokazana je štetnost temperatura od -4 °C i -5,6 °C na korijenske reznice jer su one dovele do njihovog smrzavanja. Najbolje kalendarsko vrijeme za vađenje korijenskih reznica, ovisno o godini, bilo bi u mjesecu ožujku. Utvrđena je mogućnost zakorjenjivanja korijenskih reznica hibrida paulovnije 9501 u običnoj vodi u kontroliranim uvjetima (bez svjetla, konstantna temperatura od 20 °C). Reznice su stavljene u „in vitro“ klijalicu Snijders Scientific B.V., ECD01E dana 21.12.2017. a fotografirane 21.02.2018. odnosno 62 dana od stavljanja u vodu.The genus Paulownia, family Paulowniaceae, contains about nine species and several natural hybrids which are native to China. Some important species in this genus include P. albiflora, P. australis, P. catalpifolia, P. elongata, P. fargesii, P. fortunei, P. kawakamii and P. tomentosa. More recently, numerous hybrids have been obtained by hybridisation for the purpose of increasing the rate of growth and increment, as well as develop resistance to low temperatures. In Croatia, the most commonly propagated are the Paulownia hybrids Shan Tong and 9501, although there are also other hybrids obtained by selections in some “in vitro” laboratory. The goal of this article is to explore different propagation methods of Paulownia in the nature, the problem of its invasiveness and nursery propagation by means of autovegetative macropropagation method from root cuttings. There are three phases of rooting the cuttings: initiation, induction and expression. There is direct and indirect induction. The most sensitive moment is the connecting of the conductive elements of small roots with parts of a cell. The success of root development on the cutting depends on the physiological status of the parent plant, sugar quantity, auxin metabolism, mineral nutrition, phenol metabolism and others. There are four stages of Paulownia propagation from root cuttings: digging out and finishing of root cuttings from the parent stock, pricking out the cuttings into plastic containers filled with potting media, rooting the cuttings and the establishment of a new parent stocks. The Paulownia root cuttings Shang Tong and 9501 were taken with regard to the polarity in the following way; the bottom (distal) part of the root was cut at an angle of 45 degrees and the upper (proximal) part was cut at an angle of 90 degrees. The cuttings were divided into short (8 cm) and long (15 cm) cuttings. Each group of the cuttings was additionally divided into thin and thick cuttings, making the difference visible to the naked eye. A total of 15 cuttings were taken from each group for the purpose of our research. In the experiment, one part of the cuttings was pricked out in a heated greenhouse 7 days after root excavation and the other part of the cuttings was pricked out after drying at room temperature in the plant growth chamber. The first group of 60 cuttings was taken on December 14th and pricked out in perforated 5.0 l plastic bags filled with ready-made Klasman Steckmedium rooting medium. The rooting medium was enriched with 3g/l of Osmocote Exact Standard 5-6M formulation 15-9-12+2MgO+TE, the 3rd generation of controlled release fertilizers. The cuttings were not treated with a phytohormone or rot prevention fungicides. The cuttings were pricked out in such a way that the upper surface of the cut at 90 degrees was at the level of the potting medium. The second group of 60 cuttings was dried in the Kambić RK-980 CH growth chamber. The chamber temperature was 21 °C and the relative air humidity was 40%, which equalled storage of the cuttings under constant room conditions. The cuttings were kept in the growth chamber for 5 days. Pricking out was performed on December 12th, 2017 in the same way as the first group of cuttings. The first rooting registration was done on February 19th, 2018, which in the case of the first group means 67 days after pricking out and for the second group 60 days after pricking out. Drying the Paulownia Shang Tong hybrid cuttings increased the rooting success in all the variants, and was particularly evident in thick cuttings 8 cm long and thick cuttings 15 cm long. Selecting thicker cuttings and drying them at room temperature for 5 days can be recommended because this procedure yields a significantly higher rooting percentage. Excessive moisture in the potting medium used for the Paulownia root cuttings negatively affects root system development. It was also confirmed that drying the Paulownia hybrid 9501 cuttings increases the rooting success in all the variants, with the exception of thin cuttings 8 cm long, where the rooting percentage was the same (33 %). Thick cuttings 8 cm long present a particularly interesting case, where not one single cutting which was not dried took root, while as many as 80 % of cuttings took root after being dried. Taking thicker cuttings of the Paulownia 9501 hybrid and drying them at room temperature for 5 days can be recommended, because this procedure yields a significantly higher rooting percentage. The rooting percentage of cuttings without drying would certainly be higher if the cuttings had been taken immediately after the root system was dug out with a dredge, as recommended in practice. In this case, the minimal air temperatures of -4 °C and -5.6 °C caused the root system to freeze. The average minimal air temperature in the period from December 8th to December 14th was only 0.8 °C. When the root is frozen, the bark is separated from the wood manually, and such cuttings either decay or sprouting from the lower adventitious buds. The root cuttings of the Paulownia hybrids Shan Tong and 9501 should be taken immediately after the root system of the parent plant is dug out, while the average air temperature should be above 0 °C. Our studies confirmed the harmful effect of temperatures from -4 °C and -5.6 °C on root cuttings, as such temperatures caused the cuttings to freeze. The best calendar period for digging out root cuttings, depending on the year, should be in March. It was confirmed that the root cuttings of Paulownia hybrid 9501 can also be rooted in ordinary water under controlled conditions (no light, constant temperature of 20 °C). The cuttings were placed in “in vitro” Snijders Scientific B.V., ECD01E germination table on December 21st, 2017, and were photographed on February 21st, 2018, or 62 days after being placed in the water