Programmed Cell Death in Relation to Petal Senescence in Ornamental Plants

Abstract: Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescence and the post-harvest quality of ornamentals, fruits, and vegetables. In the present paper, PCD in relation to petal senescence in ornamental plants is reviewed. Morphological, anatomical, physiological, and biochemical changes that are related to PCD in petals, such as water content, sink-source relationships, hormones, genes, and signal transduction pathways, are discussed. Several approaches to improving the quality of post-harvest ornamentals are reviewed and some prospects for future research are given.

Micropropagation of Daylily(Hemerocallis fulva)from Crown-Tip Explants and Assessment of Somaclonal Variation of in Vitro-Propagated Plants Using SCoT Markers

Determination of the somaclonal variation of in vitro-propagated plants is crucial to determine the appropriate micropropagation protocol and growth regulators for commercial scale multiplication.In this research,nine multiplication media(MM)augmented with different concentrations of 6-benzyl adenine(BA),Kinetin(Kin),and Thidiazuron(TDZ),Three rooting media(RM)supplemented with three levels ofα-naphthalene acetic acid(NAA)and three types of soil mixtures(v/v);Coco peat/Vermiculite/Sand(CVS),Peat moss/Perlite/Sand(PPS)and Peat moss/Perlite(PP)were used in the micropropagation protocol of daylily plants.MM2 showed the maximum shoot length and the number of leaves,while MM9 showed the maximum number of shoots.The RM1 showed the maximum root length and the number of roots.During acclimatization,CVS,PPS,and PP soil mixture showed similar performance except the CVS mixture showed lower performance regarding plant height and diameter.The genetic fidelity of micropropagated plants was evaluated using Start Codon Targeted(SCoT)Markers.Six SCoT primers amplified 51 scorable bands with an approximate range from 146 bp to 1598 bp size.Thirty one out of 51 loci were presented in the mother plants.40 loci were polymorphic,11 were monomorphic and 7 were unique.The amplification patterns of the micropropagated plants demonstrated genetic integrity to the mother plant ranging from 84.32 to 47.06 and somaclonal variations ranging from 52.94 with 5 mg/l BA pathway to 15.68 with 1mg/l TDZ pathway,thus demonstrating that the homogeneity and the variation of the micropropagated plants affected by the type and the quantity of the plant growth regulator used during multiplication subcultures.This research can be successfully used for other ornamental and medicinal plants’bulk multiplication,germplasm conservation,and future genetic improvement.

Selection and Configuration of Landscape Plants for the Median Strip of Suibei Highway

Landscape design and greening quality of the median strip on multi-lane highway are the most important parts of the visual impact factor. Using ornamental plants to create a comfortable greening scene on the median strip, can effectively prevent glare and improve the road driving environment. The paper studied and analysed the median strip greening status and the driving environment problems of Suibei highway in north China. On the basis of local environmental conditions, the research selected suitable landscape species to form well-proportioned landscape scenes for this highway median strip. Three sets of reference landscape configuration modes were designed for improving the median strip of Suibei highway based on the recommended landscaping plants in this paper.

道路景观植物滞尘量研究

道路景观植物作为消除大气颗粒污染物的重要方法正受到越来越广泛的重视。本文选用绵阳市道路景观植物中具有代表性的小叶榕、月季和女贞对影响植物滞尘量的因素进行研究。结果表明:小叶榕树种的滞尘量极显著地高于月季和女贞(P<0.01);小叶榕与月季混种的滞尘量显著地高于小叶榕单独种植(P<0.05);景观植物与机动车道适当的距离和栽种密度对小叶榕的滞尘和滤尘作用有一定的影响。

Differences in leaf physiological and morphological traits between Camellia japonica and Camellia reticulata

Plants of the genus Camellia are widely cultivated throughout the world as ornamentals because of their bright and large flowers.The widely cultivated varieties are mainly derived from the mutant lines and hybrid progenies of Camellia japonica Linn.and Camellia reticulata Lindl.While their geographical distributions and environmental adaptabilities are significantly different,no systematic comparison has been conducted between these two species.To investigate differences in how these plants have adapted to their environments,we measured photosynthesis and 20 leaf functional traits of C.japonica and C.reticulata grown under the same conditions.Compared with C.japonica,C.reticulata showed higher values for light saturation point,light-saturated photo synthetic rate,leaf dry mass per unit area and stomatal area,but lower values for apparent quantum efficiency,leaf size,stomatal density and leaf nitrogen content per unit mass.Stomatal area was positively correlated with light-saturated photosynthetic rate and light saturation point,but negatively correlated with stomatal density.The differences between C.reticulata and C.japonica were mainly reflected in their adaptations to light intensity and leaf morphological traits.C.reticulata is better adapted to high light intensity than C.japonica.This difference is related to the two species’ differing life fo rms.Thus,leaf morphological traits have played an important role in the light adaptation of C.reticulata and C.japonica,and might be first noticed and selected during the breeding process.These findings will contribute to the cultivation of camellia plants.

Tolerance of Chrysantemum maximum to heavy metals:The potential for its use in the revegetation of tailings heaps

To find if ornamental plants are applicable to the remediation of metal-polluted areas, the tolerance of chrysanthemum plants （Chysanthemum maximum） var. Shasta to different metals under hydroponic conditions was studied. Their responses as influenced by the mycorrhizal fungus Glomus mosseae （Nicol. ＆ Gerd.） Gerdemann ＆ Trappe BEG25 on substrates containing mine residues were also investigated. Our results showed that chrysanthemum is a metal-tolerant plant under hydroponic conditions, plants behaving as Pb-excluders, whereas Cd, Cu and Ni were accumulated in roots. Low accumulation in flowers was observed for Cd and Cu but it was concentration-dependent. Ni and Pb were not translocated to flowers. Shoot biomass was not significantly affected by the different rates of mine residue addition for both mycorrhizal and non-mycorrhizal plants. Mycorrhizal plants accumulated less Pb and Cu in both shoots and roots than non-mycorrhizal plants. Chysanthemum could be a prospective plant for revegetation of tailings and the use of inoculation may decrease plant metal accumulation in polluted soils.