Balkrishna Ghimire

Regeneration of Treeline Birch (Betula utilis D. Don) Forest in a Trans-Himalayan Dry Valley in Central Nepal

Abstract Distribution and community structure of treeline birch (Betula utilis D. Don) forest in a trans-Himalayan dry valley was studied in Manang (central Nepal) with the major focus on regeneration. Along 5 vertical transects, a total of 41 square quadrats (10 m x 10 m) were sampled to determine the importance value index (IVI) of tree species, distribution pattern of seedlings and saplings, and soil attributes. Regeneration was assessed by a density–diameter curve. Moisture plays an important role in spatial (horizontal) distribution of Betula utilis. Pure Betula forest forming the treeline was mature, with high basal area (2.3%), but mixed Betula forest at lower elevations was young. This might have developed after large-scale clear cutting of Abies spectabilis. If not severely disturbed, mixed Betula forest may be replaced by Abies spectabilis. In general, Betula utilis was regenerating, as evident from a reverse J-shaped density–diameter curve for both forests. However, the distribution of seedlings and saplings was spatially heterogeneous and appeared to depend on canopy cover. The stands with highest seedling and sapling densities of Betula utilis had no trees. Betula seedlings were absent where the tree density and basal area (BA) exceeded 20 stems/100 m2 and 1.0% respectively. It was apparent that Betula seedlings could not establish under their own closed canopy even if they produced viable seeds. Partial canopy opening may induce seedling establishment and hence continuous regeneration of Betula utilis at mature stands. The tree-line formed by Betula utilis was abrupt—the anthropo-zoogenic type—without the krummholz zone.

Leaf anatomy and its implications for phylogenetic relationships in Taxaceae s. l.

The comparative study on leaf anatomy and stomata structures of six genera of Taxaceae s. l. was conducted. Leaf anatomical structures were very comparable to each other in tissue shape and their arrangements. Taxus, Austrotaxus, and Pseudotaxus have no foliar resin canal, whereas Amentotaxus, Cephalotaxus, and Torreya have a single resin canal located below the vascular bundle. Among them, Torreya was unique with thick-walled, almost round sclerenchymatous epidermal cells. In addition, Amentotaxus and Torreya were comprised of some fiber cells around the vascular bundle. Also, Amentotaxus resembled Cephalotaxusharringtonia and its var. nana because they have discontinuous fibrous hypodermis. However, C. fortunei lacked the same kind of cells. Stomata were arranged in two stomatal bands separated by a mid-vein. The most unique stomatal structure was of Taxus with papillose accessory cells forming stomatal apparatus and of Torreya with deeply seated stomata covered with a special filament structure. Some morphological and molecular studies have already been discussed for the alternative classification of taxad genera into different minor families. The present study is also similar to these hypotheses because each genus has their own individuality in anatomical structure and stomata morphology. In conclusion, these differences in leaf and stomata morphology neither strongly support the two tribes in Taxaceae nor fairly recognize the monogeneric family, Cephalotaxaceae. Rather, it might support an alternative classification of taxad genera in different minor families or a single family Taxaceae including Cephalotaxus. In this study, we would prefer the latter one because there is no clear reason to separate Cephalotaxus from the rest genera of Taxaceae. Therefore, Taxaceae should be redefined with broad circumscriptions including Cephalotaxus.

Comparative leaf anatomy of native and cultivated Pinus (Pinaceae) in Korea: implication for the subgeneric classification

Comprehensive comparative anatomy of Pinus leaves was carried out. Some anatomical features were found to be quite useful and supported the classification of genus to subgenus and section level. The number of needles per fascicle, number of vascular bundles, position of resin ducts, shape of leaf in cross section, and distribution of stomata on the leaf surface showed remarkable variation between different species and facilitated the classification of Pinus into minor groups: subgenus, section, and subsection. The members of subgenus Pinus had two vascular bundles whereas members of subgenus Strobus had only one vascular bundle. The position of resin ducts was more consistent in subgenus Strobus than in subgenus Pinus. Interestingly, the species of subsection Strobus included in this study lacked stomata on the abaxial surface. The results indicate that the number of needles per fascicle and needle size are inversely related, and more importantly that a greater numbers of needles per fascicle lead to a more angular shape.

Effect of Seed Collection Stage and Temperature on Germination of Deutzia paniculata Nakai, the Korea Native Species

In this study, we investigated the effect of seed collection stage and alternating temperature on the germination of Deutzia paniculata (Hydrangeaceae). The seeds were collected from naturally growing D. paniculata populations in Mt. Palgong, Gyeonsangbuk-do, Korea every two weeks over a three month period from August through October, 2014, totaling five collections. We examined seed characteristics such as seed size (length and width) and weight, and germination percentages for each collection stage under four different germination temperature regimes. We also examined germination after 30 and 60 days of cold moist stratification. Each collection phase had a different germination percentage and the lowest germination percentage was observed in the seeds from phase I (average GP of 15.7%). The germination percentage was similar at the later collection phases and in the higher temperatures suggesting that later collection times and higher temperatures are optimal for D. paniculata germination. We found that the optimum collection stage with high viability and germination percentage of for D. paniculata was during the middle of the September.

Morphological and Anatomical Characteristics of Medicinal Fructus in Apiaceae

Background : As the characterization of medicinal plants is an important aspect of traditional Asian herbal medicine, this study examines the morphological and anatomical characteristics in four fructus form medicinally important plants belonging to the family Apiaceae. Methods and Results : Fruit morphology of four genera was examined using microtome sections and light microscopy. The Anethi Fructus, Anethum graveolens (Siraja) has unique wing-like and membranous lateral ribs that are, approximately wide. The Coriandri Fructus, Coriandrum sativum (Hoyuja) does not have oil ducts at the dorsal region of the mericarp and differs in the development of the dorsal ribs. The ribs appear upon drying and therefore, consist of primary and secondary ribs. The Foeniculi Fructus, Foeniculum vulgare (Hoehyang) characteristically develops three dominant dorsal ribs and has a strong aromatic fragrance. Finally, the Cnidii Fructus, Torilis japonica (Sasangja) has many oil ducts at the dorsal and carpophores regions and develops many hooked trichomes one the fructus surface. Conclusions : We conclude from this study that each plant has several prominent and distinguishing morphological and anatomical characteristics. Therefore, fruit morphology is very useful for identifying these medicinal plants. In addition, the correct use and herbal name need to be standardized for plants used traditionally in Asian medicine within Korea, China, and Japan.

Embryology of Gymnospermium microrrhynchum (Berberidaceae)

An intensive study of the embryology of Gymnospermium microrrhynchum was conducted to provide information regarding a discussion of the phylogenetic relationships of the genus, which is yet unstudied. Our results indicated that Gymnospermium is similar to other genera of Berberidaceae in terms of its embryological features. Nevertheless, newly reported and unique features are the well-developed endothelium and the undifferentiated seed coat type. Until the study of Gymnospermium, it may have been considered to be closer to Caulophyllum and Leontice in the tribe Leonticeae. These three genera share many morphological features as well as molecular similarities, by which they are kept in the same tribe, Leonticeae. However, very little detailed embryological data regarding these genera have been published thus far. Gymnospermium was characterized according to the basic type of anther wall formation as well as its glandular tapetum, successive cytokinesis in the microspore mother cell, two-celled mature pollen grains, anatropous and crassinucellate ovules with a nucellar cap, well-developed endothelium, its Polygonum type of embryo sac formation, its nuclear type of endosperm formation, and its undifferentiated seed coat type. In comparison with Nandina, there are many differences, such as the dehiscence of the anther, the cytokinesis in the microspore mother cells, the shape of the megaspore dyad, and the seed characteristics. Although we had no available detailed embryological information regarding Caulophyllum and Leontice, which are genera that are more closely related to Gymnospermium, we could deduce from the phylogenetic relationship that Gymnospermium, Caulophyllum, and Leontice are more closely related to each other than other genera of Berberidaceae on the basis of the seed characteristics.