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Under natural conditions, Syringa vulgaris blooms in May but it may be forced to produce blooming panicles in autumn, winter and early spring. To break winter dormancy, plants require high temperatures, the range of which depends on the forcing date. Forcing in November requires exposure to temperatures of ~37C. Such an exposure may affect the development of both male and female flower organs. In this work we have followed the anatomical changes in the ovule development in buds collected from plants forced in autumn, and compared them to those in plants blooming under natural conditions in May. From the earliest identifiable stages, in flowers forced in November the ovule development was delayedrelative to the normal development pattern. Ultimately, most of the ovules (83%) degenerated before the differentiation of the embryo sacs was completed. We believe that it is the high temperatures required during autumn forcing that affect the development of female gametophytes, leading to the formation of defective structures which often degenerate. This in turn may reduce the esthetic appeal of the inflorescences and reduce their commercial value.
Celem niniejszej pracy było określenie wpływu różnych temperatur na długość cyklu pędzenia oraz jakość kwiatostanów lilaka pospolitego ‘Mme Florent Stepman’ w terminie listopadowym. Krzewy pędzono w dwóch temperaturach: 15°C przez cały cykl pędzenia oraz w wysokich temperaturach, standardowych dla tego terminu. Wysokość temperatury miała istotny wpływ na długość trwania poszczególnych faz fenologicznych oraz jakość kwiatostanów u lilaka. Pędzenie w 15°C trwało 49 dni w porównaniu z pędzeniem standardowym trwającym średnio 23 dni. W tej kombinacji faza pęcznienia pąka kwiatostanowego rozpoczęła się 26. dnia pędzenia. Kwiatostany z krzewów pędzonych w 15°C były bardziej dekoracyjne od kwiatostanów z krzewów pędzonych w temperaturach standardowych. Wyniki doświadczeń zdają się zaprzeczać powszechnie panującemu przekonaniu, że dla przełamania spoczynku bezwzględnego w listopadzie konieczne jest stosowanie bardzo wysokich temperatur początkowych. Temperatura 15°C pozwala pobudzić pąki do wzrostu, choć trwa to 3 tygodnie dłużej niż po zastosowaniu wysokich temperatur.
Studies on the development of common lilac cv. Mme Florent Stepman inflorescence buds and flowers were carried out in 2001-2002 in order to observe the development of flower organs before and after winter dormancy during the following phenological phases: inflorescence bud swelling, inflorescence elongation, flower bud whitening, flower bud swelling and flowering anthesis. The hypogynous, actinomorphic and perfect flower conforms to the general pattern of the Oleaceae. The calyx is four-lobed, and the four-lobed corolla is gamopetalous with a cylindrical basal tube. Two stamens are basally fused with the corolla. The anthers are tetrasporangiate, with a uniseriate epidermis, bilayered endothecium, single middle layer, and secretory, binucleate tapetum. Microspore tetrads are isobilateral and the pollen grains are spherical, three-colpate and two-celled. The ovary is superior and bilocular. Four anatropous, unitegmic and tenuinucellar ovules are formed. The female gametophyte development is Polygonum-type. Flower primordia differentiation starts in midsummer and lasts until autumn. Before entering dormancy, microspore meiosis was discernible in flowers in the lower part of the inflorescence. The ovular primordia differentiate after winter dormancy. During inflorescence bud breaking after winter dormancy, pollen mother cells in anthers and ovule primordia were observed. During inflorescence elongation, pollen mother cell meiosis and microspore tetrads occured in anthers, and the archesporial cell of the megaspores was present in ovules. During flower bud whitening and flower bud breaking, young microspores were observed in anthers, and developing megaspores were visible in ovules. In the last phenological phase, anthers dehisced and the female gametophyte was organized.
The paper shows differences in morphological and anatomical features of the Scots pine (Pinus sylvestris L.) growing on former agricultural and forest lands. It was found that at the same age and in the same climatic conditions Scots pines from former agricultural land had larger stem dimensions and needle sizes as compared with the trees growing on forest land. These results lead to an interesting conclusion connected with future afforestation and reforestiation in the Krynki Forest District.
Bedding plants are often subjected to soil water deficit – either after planting and/ or during the market chain. Methods to alleviate the negative water stress effects are sought for to preserve ornamental values of plants. The aim of this study was to evaluate the response of two bedding plants, Ageratum houstonianum Mill. and Salvia splendens Sellow ex Scult., to water stress and treatments with calcium chloride aimed to alleviate drought effects. Plants were subjected either to 45 days of periodical stress (five cycles when watering was off for 5 consecutive days, followed by four cycles on for 5 consecutive days) or 10 days of radical drought (complete water withdrawal). On the first day, before the onset of drought, plants were watered with 0.5% Ca or 1% Ca w/v as a solution of calcium chloride (5 g or 10 g Ca per 1 dm3 of the growing substrate). The similarly Ca-treated but routinely watered plants provided controls to evaluate the water shortage effects. Plant height, inflorescence length/number, leaf number, leaf area (in Salvia splendens only), aboveground plant part weight, and root weight (in Salvia splendens only) as well as leaf relative water content (RWC) were measured at the beginning and at the end of the experiments. Water withdrawal during 10 days of growth (radical drought) reduced by half RWC in leaves of withering Salvia splendens and Ageratum houstonianum plants. Its effects on the growth parameters were less pronounced and mitigated by Ca applications. Also in the periodically stressed plants of both species, RWC and most growth parameters were reduced by water shortage but Ca applications alleviated the negative stress effects.
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Occurrence of blockage in cut stems of Clematis L.

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During vase life of cut flowers obstructions in stem xylem vessels develop. Such obstructions may restrict water uptake in stems and its transport towards flowers, thus lowering their ornamental value and longevity. Clematis is a very attractive plant which can be used as a cut flower in floral compositions. However, nothing is known about the histochemical or cytological nature of xylem blockages occurring in cut stems of this plant. Observations carried out on Clematis cv. ‘Solidarność’ proved that tyloses appeared as a principal source of xylem blockage in cut stems. The preservative composed of 200 mg × dm-3 8-HQC (8-hydroxyquinolin citrate) and 2% sucrose arrested development of xylem blockage, while the vessels in stems kept in water were filled with tyloses or an amorphic substance. PAS reaction proved that polysaccharides were present in the xylem occlusions, whereas no homogalacturonans were immunolocalized in tyloses using JIM 5 and JIM 7 antibodies. The present study provides new information on the origin of xylem occlusions in clematis and their development in two different vase solutions. Such information can be useful to develop proper postharvest treatments aiming to improve keeping qualities of this new cut flower.
Badania prowadzone w latach 1997 - 2002 miały na celu zbadanie wpływu terminu pędzenia, liczby oraz rodzaju pąków kwiatostanowych na długość i jakość wiech lilaka pospolitego. Obserwacje prowadzone w 16 terminach w szklarni oraz 3 terminach w tunelu foliowym wykazały, że im wcześniejszy jest termin pędzenia tym krótsze i gorszej jakości są kwiatostany. Ponadto we wczesnych terminach rozwój kwiatów w wiesze jest bardzo nierównomierny. Badania wykazały wpływ rodzaju pąka szczytowego na długość i jakość kwiatostanów oraz wpływ liczby pąków wierzchołkowych na dynamikę rozwoju kwiatostanów. Nie znaleziono powiązań między liczbą pąków wierzchołkowych, a końcową długością kwiatostanów.
Recently, the programmed cell death (PCD) is studied in the context of the postharvest longevity of cut flowers with the goal of slowing down the processes that ultimately lead to flower death, and to ensure a long display life of cut plant material. In this study, the phenomenon of PCD in petals of common lilac (Syringa vulgaris L.) was observed, aimed to compare degradation of petal cells in flowers blooming under natural conditions with those forced in November. For the early lilac forcing, a deep dormancy has to be broken by high temperatures 35–37 C negatively affecting postharvest life of cut branches. The trials included as well the observation of the effect of two flower preservatives on the PCD in order to see if the prolongation of the lilac vase life was associated with a delay in the onset of the PCD symptoms. The vase life of cut lilacs was significantly increased by both preservatives. The first symptoms of PCD were evident in the flower bud stage. In petals from forced shrubs, the first symptoms of cell degradation were much more advanced than in lilacs blooming naturally in May. In forced flowers held in the preservatives, the degradative changes in cells occurred later than in those kept in water, but they were accelerated relative to a flower developmental stage.
Oceniono wpływ terminu przyspieszania kwitnienia w tunelu foliowym lilaka pospolitego 'Andenken an Ludwig Spaeth’ na tempo wzrostu kwiatostanów oraz na końcową długość szczytowych wiech kwiatostanowych. W badaniach stwierdzono, że termin przyspieszania wpływa na tempo wzrostu kwiatostanów u lilaka pospolitego ‘Andenken an Ludwig Spaeth’. Największe różnice w długości kwiatostanów we wszystkich terminach przyspieszania stwierdzono między 27 a 29 dniem cyklu. Nie stwierdzono wpływu terminu przyspieszania kwitnienia na końcową długość kwiatostanów.
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