Effects of stock loading and planting distance on the growth and production ofGracilaria chilensis in rope culture

Through experimental manipulation of stock loading and planting distances in rope culture, this study evaluates the hypothesis that optimum density for growth and production ofGracilaria chilensis vary within a bed. Small packages ofGracilaria disposed at short distances exhibit higher growth and production rates in the landward ends of ropes than larger packages of seaweed disposed at longer distances. In these experiments, the landward end of ropes faces estuarine conditions, with reduced salinities and increased sediment loads during low tides. The interacting effects of stocks loading and position in the rope can affect growth and production rates so much as to nullify the 3.5-fold summer increments in production that occur in these estuarine beds of southern Chile. It is concluded that through manipulation of planting distances and stock loading, the production of this species could be increased up to 35% in some areas.     

Gracilaria conferta and its epiphytes: 3. Allelopathic inhibition of the red seaweed byUlva cf.lactuca

In a previous study (Svirski et al., 1993), it was found that growth inhibition ofGracilaria spp., when cultured in the presence ofUlva cf.lactuca, was not due to shading or nutrient depletion, but seemed to be caused by competition for inorganic carbon or some type of allelopathy. In the present study, we attempted to differentiate between these two possible influences by (1) growing the two algae in biculture under various conditions, but keeping inorganic carbon levels constant and measuring net photosynthesis, respiration and growth rates, and by (2) measuring growth rates ofGracilaria spp. in the presence of extracts derived from media previously used to growUlva cf.lactuca.Both net photosynthesis and growth rates ofGracilaria spp. in biculture were inhibited, despite CO₂ (and also HCO₃ ^–) levels being kept constantly high in the culture media. It is likely that these responses were due to markedly enhanced rates of dark respiration inGracilaria spp. when grown together withUlva cf.lactuca. Growth ofGracilaria spp. was also inhibited by extracts derived from seawater in whichUlva cf.lactuca had previously been grown. The strong inhibition by ethyl acetate and chloroform extracts indicate an allelopathic effect onGracilaria spp.     

Co-occurrence of the cirolanid isopodEurydice nipponica Bruce & Jones and the ghost shrimpCallianasa japonica Ortmann on an intertidal sand flat

On a moderately protected intertidal sand flat in west Kyushu, Japan, most of the population of the cirolanid isopodEurydice nipponica Bruce & Jones (89%–100%) was found in the zones occupied by the thalassinidean ghost shrimpCallianassa japonica Ortmann in July, August and December 1980.C. japonica later extensively expanded its habitat, and in July 1984, when almost the whole sand flat had been densely populated byC. japonica, the range of the distribution ofE. nipponica was the same as that ofC. japonica with a density about 10 times greater than in July 1980. The occurrence ofE. nipponica has previously been recorded from several exposed sandy beaches as well as their adjacent subtidal areas of well oxygenated sands along the coast of Kyushu, but not on more protected shores like the present sand flat. It is suggested thatC. japonica, through its bioturbating activities, produces sediment characteristics approximating those of the exposed sandy beaches which are the preferred habitat ofE. nipponica. It is supposed thatE. nipponica is a facultative commensal ofC. japonica. In a field experiment to excludeC. japonica and to detect its positive influence onE. nipponica, the densities ofE. nipponica were found to be lower in the experimental plots than in the intact plots. Statistically, however, the difference was only weakly significant, and the possible reasons for this are discussed.     

A taxonomic study of KoreanSmilacina

Several taxonomic problems of KoreanSmilacina were examined by statistical methods, based on morphological data. Consequently,S. davurica described in Korean flora differs greatly from originalS. davurica, and closely related toS. bicolor morphologically. Therefore, the present authors treated this new taxon as a variety ofS. bicolor, S. bicolor var.flavovirens N. S. Lee et J. Y. Kim var. nov (“Yondusomdae” in Korean). The distribution in South Korea ofS. bicolor var.bicolor is known as only Mt. Chiri, but this species is collected in Mt. Dukyou, also. The bounds of morphological variations ofS. japonica var.japonica, the short plant size and no hairs on the stem, were revealed. The morphological characteristics ofS. japonica var.japonica andS. japonica var.mandshurica is obscure to distinguish. According to the present study,S. japonica var.mandshurica differs fromS. japonica var.japonica in plant size, size of adaxial leaf epidermal cell, ratio of style/ovary length and shape of stigma. The unrecorded taxon in Korean flora,S. robusta, was given a new Korean name as “Kunsomdae.” AlthoughS. japonica var.mandshurica is the variety ofS. japonica var.japonica, it is more closely related toS. robusta than toS. japonica var.japonica.     

Comparative development of gametophytes ofOsmunda lancea andO. japonica (osmundaceae): Adaptation of rheophilous fern gametophyte

Development of the gametophytes of a rehophytic fernOsmunda lancea and a related dryland speciesO. japonica was examined, and adaptation ofO. lancea gametophytes to rheophytic habitat was discussed. The spores ofO. lancea were larger in size and contained larger oil droplets than those ofO. japonica. The germination rate was similar. In agar culture,O. lancea gametophytes grew more rapidly and reached reprudctive maturity earlier thanO. japonica, although there was no prominent gross-morphological difference in developing and mature gametophytes. Sporophyte formation ofO. lancea took place at roughly two times higher rate than that ofO. japonica. TheO. lancea gametophytes might be adapted to the periodically flooded habitat by shortening its life, which is a different strategy from that of the sporophytic generation.     

Assessment of populations ofGracilaria chilensis (Graeilariales,Rhodophyta) utilizing RAPDs

Phenotypic variability and mixing of material due to massive cultivation for commercial purposes has contributed to the taxonomic confusion ofGracilaria in Chile. At least four species with cylindrical thalli and similar morphology have been recorded. However, since establishment ofG. chilensis, most of the collected thalli have been attributed to this species despite the lack of diagnostic features. In an attempt to resolve whetherGracilaria from 3 localities where it grows in natural and artificial populations belongs to the same species, gametophytic samples were compared by applying RAPD-PCR to their total DNA. This was analysed using 25 different 10-mer primers from which 21 revealed polymorphism within and between populations. Similarity matrices and cluster analyses were performed based on the presence/absence of bands representing fragments of DNA generated by random amplification. Similarity values between two of the populations were equivalent to those detected within a third, indicating the mixing of genetic material due to transplant between the two former localities. Similarities between samples of ChileanGracilaria andG. tenuistipitata from Sweden are considerably lower (0.45–0.53) than those between populations from Chile (0.74–0.88), confirming the existence of a single specific taxon,G. chilensis, in these three localities.     

Adaptation of stomatal response ofCamellia rusticana to a heavy snowfall environment: Winter drought and net photosynthesis

The adaptation ofCamellia rusticana, an evergreen broad-leaved shrub found in areas of heavy snowfall in Japan, to heavy snowfall environments, and the mechanisms by which it is damaged in winter above the snow, were investigated. The stomatal response and photosynthetic characteristics ofC. rusticana were compared to those ofCamellia japonica found in areas of light snowfall. In field conditions, the mean net photosynthesis ofC. rusticana at photon flux density (PFD) over 200 μmol m⁻²s⁻¹ (Pn(_>200). was 50% larger than that ofC. japonica, but in both light saturated and CO₂ saturated conditions, the O₂ evolution rate (Pc) ofC. rusticana was not different from that ofC. japonica. Mean leaf conductance at PFD over 200 μmol m⁻²s⁻¹ (gl(_>200)) was about 100% larger than that ofC. japonica in the field. The Pn(_>200)) was 50% ratio ofC. rusticana was 37% higher than that ofC. japonica which suggests thatC. rusticana's larger Pn(_>200) can be explained by its larger gl(_>200). WhenC. rusticana trees wintering underneath the snow were projected above it, the leaves of these plants showed serious drought within five days in non-freezing conditions. Their Pc and the maximum stomatal conductance decreased by half and did not recover. The leaves ofC. rusticana showed larger gl(_>200) and a less sensitive stomatal response to the decrease of leaf water potential than that ofC. japonica. The stomata characteristics ofC. rusticana caused larger net photosynthesis than that ofC. japonica during the no snow period, and caused the need for snow cover in winter as protector from winter drought.     

Influence of enhanced CO2 on growth and photosynthesis of the red algaeGracilaria sp. andG. chilensis

The influence of elevated CO₂ concentrations on growth and photosynthesis ofGracilaria sp. andG. chilensis was investigated in order to procure information on the effective utilization of CO₂. Growth of both was enhanced by CO₂ enrichment (air + 650 ppm CO₂, air + 1250 ppm CO₂, the enhancement being greater inGracilaria sp. Both species increased uptake of NO₃ ^– with CO₂ enrichment. Photosynthetic inorganic carbon uptake was depressed inG. chilensis by pre-culture (15 days) with CO₂ enrichment, but little affected inGracilaria sp. Mass spectrometric analysis showed that O₂ uptake was higher in the light than in the dark for both species and in both cases was higher inGracilaria sp. The higher growth enhancement inGracilaria sp. was attributed to greater depression of photorespiration by the enrichment of CO₂ in culture.     

Comparative leaf development ofOsmunda lancea andO. japonica (osmundaceae): Heterochronic origin of rheophytic stenophylly

Comparative development of the narrow pinnules of rheophyticOsmunda lancea and of the broad pinnules of a related dryland species,O. japonica, was examined and the origin of rheophytic stenophylly was discussed. The mature leaves and their various parts ofO. lancea are smaller and narrower than those ofO. japonica. The young pinnules ofO. lancea at the initiation of cell expansion are smaller than those ofO. japonica. The growth pattern of the pinnules is fundamentally the same in the two species, but pinnule growth period is shorter inO. lancea than inO. japonica. While the largest growth rate in pinnule length is quite similar, inO. lancea the pinnules are less elongated and much less broadened during ontogeny. Cell expansion in the mesophyll and epidermis proceeds acropetally and toward the margin along the axes of costules and veins. Although the numbers of mesophyll and epidermal cells between two adjacent veinlets are almost the same inO. lancea andO. japonica, during the subsequent growth period inO. lancea, the cells expand to a smaller extent and the veinlets become more narrowly oblique to the costule. This oblique distortion of laminar segments framed by veins causes stenophylly, an allometric modification. The stenophylly ofO. lancea is believed to have arisen by heterochronic evolution, in particular, progenesis.     

Flora Palinologica Italiana,Sezione Aeropalinologica-Specie esotiche S229:Thuja orientalis L. (Cupressaceae); S230:Cryptomeria japonica (L. fil.) D. Don (Taxodiaceae)

Summary The morphopalynological cards ofThuja orientalis L. and ofCryptomeria japonica (L. fil.) D. Don were illustrated as part of a more comprehensive study on ornamental Pinophyta. Pollens from the original area of the two species were also compared with grains coming from plants cultivated in Italy. In the case ofCryptomeria japonica (L. fil.) D. Don DV, D01, D02, exine, min. and max. diameters, calculated on a japanese sample, differed significatively from the italian sample. In the case ofThuja orientalis L. no significant differences were observed. Pollen from the two italian sites did not show significative differences in size and shape. Pollens acetolysed with the traditional method (Erdtman, 1960) were compared with pollens treated with the Tatzreiter method (1985). Morphometric analysis showed similar values for both species.     

Saldanha Bay,South Africa: recovery of Gracilaria verrucosa (Gracilariales,Rhodophyta)

Since World War II the greater Saldanha Bay lagoon system, South Africa, has been an important Gracilaria producer. Two agar factories, built in the 1960's, used Gracilaria from Saldanha Bay as their raw material. In the early 1970's the industry was destroyed as a result of dredging and marine construction operations to establish a harbor in the bay for loading ore. These environmental changes destroyed stocks and prevented the previously significant beachings of the seaweed from occurring. After a few years of no or very low commercial production, the resource slowly started to recover. The size of Gracilaria drifts increased over the following eight years to approximately one-third of the original output. This trend seems to continue. Although the stocks and resultant drifts are unlikely to recover fully to their original quantity, current production is already sufficient to ensure re-establishment of a seaweed industry in Saldanha Bay. This could have considerable socio-economic impact on the area.     

Comparative leaf morphology of young sporophytes of rheophyticOsmunda lancea and drylandO. japonica

Field and morphological observations were made of the young sporophytes of rheophyticOsmunda lancea and its related drylandO. japonica, and the rheophyte's adaptation in the early sporophytic stages was discussed. Mature plants ofO. lancea andO. japonica do not occur in dryland and rheophytic habitats, respectively, but their very young sporophytes rarely grow there. The young sporophytes ofO. lancea differ considerably from those ofO. japonica in having the relatively short petioles with thin-walled epidermal cells, early lamina partition, cuneate leaf- and pinna-base, oblique (not horizontal) lamina disposition, a fine network of spongy tissue in the 4th and older leaves, and dense epicuticular wax deposits on leaf epidermis. They seem to relate to the flexibility of petioles and the toughness and flood-tolerance of blades, and make the young sporophytes adapted to the rheophytic habitat.Osmunda japonica lacking those characteristics disappears from the rheophytic habitat during the early ontogenetic stages.     

Amylostereum laevigatum associated with the Japanese horntail,Urocerus japonicus

The fungus associated with the Japanese horntail,Urocerus japonicus, in Kochi, Kagawa and Ehime Prefectures was studied. Cultures isolated from the mycangia of 113 adult females of the horntail showed the same cultural characteristics. Four of basidiocarps found on felled logs ofCryptomeria japonica were identifieds asAmylostereum laevigatum based on morphological characteristics. This was the first record ofA. laevigatum from Japan. The cultures isolated from the basidiocarps had the same cultural characteristics as those from the mycangia ofU. japonicus. One mycangial isolate produced basidiocarps on artificially inoculated stem segments ofCr. japonica after a 6-mo incubation and was identified asA. laevigatum. One isolate from the basidiocarps ofA. laevigatum and one from the mycangium ofU. japonicus were artificially inoculated into five trees each ofChamaecyparis obtusa andCr. japonica. The wood of all inoculated trees showed discoloration, with no difference in shape and pattern of discoloration between the two isolates. The inoculated fungi were reisolated from the areas of discoloration in the inoculated trees.     

Cultivation of Gracilaria in outdoor tanks and ponds

This review deals with the major problems of unattached Gracilaria intensive cultivation in outdoor tanks and ponds. These problems are presented through the main variables affecting the Gracilaria annual yield and the updated solutions evolved. The physical variables include tank and pond structure, seawater characteristics such as velocity, agitation practice, exchange rate, and salinity, light characteristics such as quantity and quality, and temperature modelling. The chemical variables include nutrient composition and regime of application, and inorganic carbon supply with the pH changes involved. The biological variables include seaweed density, epiphyte competition, grazer damage, bacterial disintegration, integrated mariculture and strain selection. The experience gained in the Israeli research on Gracilaria cultivation is discussed in view of other Gracilaria and seaweed intensive cultivation research.     

Temperature responses of economically important red algae and their potential for mariculture in Brazilian waters

Data are presented on temperature responses, based onin vitro growth performance, of eight species of colloid-producing red algae; these include the five most important commercial species of agarophytes in South America. The temperature optima do not conform strictly to geographic distribution, and intolerance to high temperature is not the factor that controls the spreading of temperate species ofGracilaria to warmer areas. WithinPterocladia capillacea (Gmelin) Bornet et Thuret, populations from two distinct localities had different responses to temperature optima. Data suggest that the disjunct distribution of this species in the American Atlantic is due to its poor performance at temperatures above 26 °C. The fastest maximum growth rate was observed inHypnea cornuta (Lamouroux) J. Agardh (doubling time 2.8 d), and the slowest inP. capillacea from Cabo Frio (doubling time 50.0 d). All the species studied, including the valuable Chilean and Argentinean species ofGracilaria, could tolerate the temperature regimes of the Brazilian waters.     

Structure of primary Japanese beech (Fagus japonica maxim.) forests in the Chichibu Mountains,central Japan,with special reference to regeneration processes

The floristic composition, structure and dynamics of three primaryFagus japonica stands were investigated in the Chichibu Mountains.F. japonica was dominant [RD(%): 64.9–87.0] and showed a slightly inverse J-shaped DBH class distribution in the quadrats [No. of canopy stems (H>20m): 87–138/ha]. The stems ofF. japonica for each size were distributed in the form of colonies, being scattered almost uniformly, and arranged in positive association with each other. Detailed examination of the bases of the stem groups forming colonies revealed that most of them originated from the bases of dead mother stems and that they were from common stools [No. of large stems (H>10 m) per stool: 6–11]. Among six major canopy gaps observed, only one included stems sprouting from the outer part ofF. japonica stools, while all the others were occupied by individuals of species other thanF. japonica. After tree-fall, several undercanopyF. japonica stems remained. Thus canopy gaps in these forest stands recovered through the sprouting of remainingF. japonica stools or by new sprouting ofF. japonica individuals adjacent to the gaps. However, it was considered difficult to fill canopy gaps only with sprouts when the distance between the center of a gap and that of a stool surpasses the crown vector. Such places that are not fully occupied by sprouts will be filled by individuals of other canopy and/or under-canopy species.     

Spatial genetic structure within two populations of a self-incompatible perennial,Chionographis japonica var.japonica (Liliaceae)

Intrapopulational spatial genetic structure was examined in two populations ofChionographis japonica var.japonica, a self-incompatible perennial, by spatial autocorrelation analysis of enzyme polymorphism. Although most spatial autocorrelation indices (Moran'sI) in the shortes distance class were significantly positive, most in the other distance classes did not significantly deviate from the values expected from random distributions of genotypes in both populations. This contrasts with a spatial genetic pattern previously reported for a population of the predominantly selfing congener,C. japonica var.kurohimensis, indicating that pollen-mediated gene flow highly impedes genetic substructuring within populations of outcrossingC. japonica var.japonica. Genetic similarity in very proximate distance found in outcrossingC. japonica var.japonica is probably due to restricted dispersal of seeds.     

Photosynthesis and photoinhibition of two green macroalgae with contrasting habitats

We evaluated light-related traits ofUlva pertusa Kjellman from the intertidal and upper subtidal zones, and ofUmbraulva japonica (Holmes) Bae & Lee (formerlyUlva japonica) within its upper growth limit of 10 m, in Korean coastal regions.U. pertusa showed significantly higher maximum photosynthetic rates, photosynthetic efficiency, saturating irradiances, and total pigment contents. However, green light-use efficiency at limiting irradiances was notably higher inU. japonica, possibly due to the presence of green light absorbing pigments like siphonaxanthin and siphonein. Non-enzymatic antioxidation capacity as determined by DPPH (α,α-diphenyl-β-picrylhydrazyl) radical scavenging rate was markedly higher inU. pertusa (50.49%) than inU. japonica (8.85%). Both species showed a substantial decrease in optimal photosystem (PS) II efficiency (F_v/ F_m) with increasing PAR doses despite the degree of photoinhibition being more marked inU. japonica. After 24 h in dim light,U. pertusa rapidly and almost fully recovered F_v/ F_m within an hour whileU. japonica exhibited slow and incomplete PSII recovery over the full recovery period. A significant depression in photosynthetic activity with monochromatic UV-B radiation was observed inU. japonica only, followed by slight recovery in dim light. Light use efficiency and high irradiance tolerance may be important ecological axes along which the niche separation of green foliose algae occurs in Korean coastal waters.     

The taxonomy and distribution ofEuchresta japonica (Leguminosae)

The taxonomic position ofEuchresta trifoliolata is discussed, and it is concluded that it is identical withE. japonica. Consequently,E. japonica can be considered to be discontinuously distributed between SW. Japan and S. China and represents a unique pattern of distribution, which has not been known for the flora of Japan and China.E. japonica is also considered to represent a relic distribution pattern.     

Associational plant refuges: convergent patterns in marine and terrestrial communities result from differing mechanisms

Summary An associational plant refuge occurs when a plant that is susceptible to herbivory gains protection from herbivory when it is associated with another plant. In coastal North Carolina, the abundance of the palatable red alga Gracilaria tikvahiae is positively correlated with the abundance of the unpalatable brown alga Sargassum filipendula during times of increased herbivore activity. To see if grazing by the sea urchin Arbacia punctulata could generate this pattern, controlled experiments were conducted in out-door microcosms and in the laboratory. Gracilaria beneath a canopy of Sargassum was eaten significantly less than Gracilaria alone. When Arbacia were excluded, Gracilaria alone grew significantly more than Gracilaria beneath Sargassum, demonstrating that Sargassum is a competitor of Gracilaria. Experiments investigating Sargassum's deterrent role indicated that Sargassum decreased the foraging range of Arbacia and the rate at which it fed on Gracilaria. Additional experiments with plastic Sargassum mimics indicated that the decreased grazing on Gracilaria was not a result of Sargassum morphology, but was probably attributable to some chemical characteristic of Sargassum. The pattern of increased grazing in monocultures (only Gracilaria present) versus polycultures (both Gracilaria and Sargassum present) demonstrated in this study also has been demonstrated for plant-insect interactions in terrestrial communities. In these communities, insect density is higher in monocultures than in polycultures because insects find and immigrate to monocultures more rapidly, and once in a monoculture, they emigrate from them less often than from polycultures. In this study, urchins did not find and immigrate to monocultures more rapidly, nor did they tend to stay in them once they were found; in fact, they emigrated from monocultures of Gracilaria more rapidly than from Gracilaria and Sargassum polycultures. Increased grazing in Gracilaria monocultures resulted from increased rates of movement and feeding of individual herbivores, not from increased herbivore density as has been reported for terrestrial systems.