J. H. Martin Willison

An assessment of the distribution of deep-sea corals in Atlantic Canada by using both scientific and local forms of knowledge.

More than 27 species of deep-sea corals have been identified off Atlantic Canada but their distributions are largely unknown. Bottom trawling is recognized as a threat to deep-sea corals in Atlantic Canada but the degree of damage has not been quantified. It is difficult to assess the level of conservation required for these organisms without basic information about their distribution. This study attempts to improve our knowledge of the distribution of deep-sea corals in Atlantic Canada.

An unusual (4-O-methyl-d-glucurono)-d-xylan isolated from the mucilage of seeds of the quince tree (Cydonia oblonga)

Abstract The major water-soluble polysaccharide in the mucilage of the seeds of the quince tree, Cydonia oblonga , is a partially O -acetylated(4- O -methyl- d -glucurono)- d -xylan having an exceptionally high proportion of glycuronic acid residues. The 4- O -methyl-α- d -glucopyranosyluronic and α- d -glucopyranosyluronic acid groups are linked to positions 2 of a (1 → 4)-β- d -xylan that is somewhat branched through the 2-positions. The O -acetyl groups are linked to the β- d -xylopyranosyl residues. The molar proportions of d -Xyl, 4- O -Me- d -GlcA, d -GlcA, and O -Ac are ∼ 2:0.8:0.2:1.

Architecture of the fluid cellulosic arrays in the epidermis of the quince seed

Summary— Using thin‐sectioning for electron microscopy, including the careful examination of a long series of sections which contained several complete cells, we describe the form of the contents of the unusually enlarged distal periplasmic space in the epidermis of the seeds of Cydonia oblonga. The major feature is a large stack of cellulosic material arranged helicoidally, which previous work has indicated is fluid and similar to a cholesteric liquid crystal. This stack has a serrated margin, which is interpreted as indicating a surface shaped like that of a screw or a concertina. The overall shape based upon artistic reconstructions from serial sect?? shows great ?? variability, due in part to the limits set by the enclosing cell walls. This together with observations of variation in helicoidal pitch and of helicoidal arc reversal, indicates that the crystals are highly plastic in form. It is suggested that the form is determined by a combination of intrinsic and extrinsic factors. Not all microfibrils in the periplasmic pocket are arranged helicoidally, and it is argued that the coexistence of helicoidal and non helicoidal microfibrillar arrays indicates that a gradient of an agent which controls cellulose microfibrillar architecture is present. This may indicate that cell wall architecture can similarly be determined by subtle regulation of agents which control helicoidal pitch.

Diversity and Above-Ground Biomass Patterns of Vascular Flora Induced by Flooding in the Drawdown Area of China's Three Gorges Reservoir

Hydrological alternation can dramatically influence riparian environments and shape riparian vegetation zonation. However, it was difficult to predict the status in the drawdown area of the Three Gorges Reservoir (TGR), because the hydrological regime created by the dam involves both short periods of summer flooding and long-term winter impoundment for half a year. In order to examine the effects of hydrological alternation on plant diversity and biomass in the drawdown area of TGR, twelve sites distributed along the length of the drawdown area of TGR were chosen to explore the lateral pattern of plant diversity and above-ground biomass at the ends of growing seasons in 2009 and 2010. We recorded 175 vascular plant species in 2009 and 127 in 2010, indicating that a significant loss of vascular flora in the drawdown area of TGR resulted from the new hydrological regimes. Cynodon dactylon and Cyperus rotundus had high tolerance to short periods of summer flooding and long-term winter flooding. Almost half of the remnant species were annuals. Species richness, Shannon-Wiener Index and above-ground biomass of vegetation exhibited an increasing pattern along the elevation gradient, being greater at higher elevations subjected to lower submergence stress. Plant diversity, above-ground biomass and species distribution were significantly influenced by the duration of submergence relative to elevation in both summer and previous winter. Several million tonnes of vegetation would be accumulated on the drawdown area of TGR in every summer and some adverse environmental problems may be introduced when it was submerged in winter. We conclude that vascular flora biodiversity in the drawdown area of TGR has dramatically declined after the impoundment to full capacity. The new hydrological condition, characterized by long-term winter flooding and short periods of summer flooding, determined vegetation biodiversity and above-ground biomass patterns along the elevation gradient in the drawdown area.

Phenolics of suberized envelopes generated by isolated tomato locule protoplasts

Abstract The phenolic compounds of the suberized multilamellar wall secreted during a 7-day culture period by protoplasts isolated from tomato fruit locule tissue were studied. Phenols constituted 25% of the total monomers obtained from the suberin extract. In descending quantitative order, the major phenols were vanillin, p -coumaric acid, p -hydroxybenzaldehyde and syringaidehyde.

Restoring ecosystem services to littoral zones of rivers in the urban core of Chongqing, China

Two examples of the creation of naturalized areas in the littoral zone of the Three Gorges Reservoir in the urban core of Chongqing City, China, are described. The areas were created for the purpose of restoring ecological functions and services. Plants were selected based on surveys of natural wetland vegetation in the region, and experiments were conducted to discover the capacity of species of interest to survive the sometimes extreme hydrological regimes at the sites. Novel methods were developed to stabilize the plants against the rigors of extreme summer floods and constant swash, notably zigzag berms of rocks wrapped in iron mesh. The areas include native reeds, grasses, shrubs, and trees. Plant communities in the areas are zoned according to flooding stress, and their structure is less stable at lower elevations that are subjected to greater stress. The tall grass Saccharum spontaneum (widespread in Southern Asia) and the tree Pterocarya stenoptera (native to Southwest China) are notable for their utility at these sites in the center of a large city. Communities of tall reeds and grasses have become so dense and stable that they now provide the ecosystem services of capturing river sediments and resisting erosion of the river banks. It is recommended that extensive greening of the riparian zones in urban areas of the Three Gorges Reservoir be conducted for the purpose of providing ecosystem services, based in part on the experiences described here.

Growth and changes of endogenous hormones of mulberry roots in a simulated rocky desertification area.

We studied the growth of roots of white mulberry (Morus alba) trees in response to different water and nutrient conditions in sets of three or five containers connected via small pipes and arranged so as to simulate the heterogeneous soil conditions associated with rocky desertification. The experiment was conducted to improve understanding of the adaptation of M. alba to this stressful environment. The trees were grown for a year under constant water and nutrient conditions in the soils within each container of any set of containers. Differences in root activity and endogenous hormones within root tips were measured at the end of the experiment. We compared four treatment groups: H (variable moisture among containers), F (variable nutrients among containers), HF (both moisture and nutrients varied among containers), and CK (non-varied control). Results showed the following: (1) Mulberry roots showed obvious hydrotropic and chemotropic growth patterns, but chemotropism did not occur in the condition of water shortage. (2) Measurement of growth indices (root surface area, total root length, number of root tips, root biomass) showed that growth status was best in group HF once the roots were able to access containers with sufficient water and nutrients, followed by group H. The indices were significantly poorer in groups F and CK. (3) The content of auxin, cytokinin, and gibberellins in roots under soil drought conditions were lower than under wetter soil conditions. In contrast, abscisic acid content and root activity were higher under soil drought conditions than under wetter soil conditions. The results indicated that water is the key factor restricting growth of white mulberry trees in areas of rocky desertification but that the trees adjust endogenous hormones in their roots to promote tropic growth and obtain sufficient moisture and nutrients over the long term. Moreover, under long-term drought stress conditions, mulberry trees retained high root activity which appears to be adaptive in that all of the trees survived.

Suitability of Taxodium distichum for Afforesting the Littoral Zone of the Three Gorges Reservoir

The littoral zone ecosystem of the Three Gorges Reservoir (TGR) has become significantly degraded by annual cycles of prolonged winter flooding and summer drought. For purposes of flood control and sediment management, the water level in the reservoir is lowered by 30 m during the summer monsoon season and raised again to 175 m above sea level each year at the end of the monsoon period. To explore an effective way to promote biodiversity and associated ecosystem services, we examined Taxodium distichum as a species for afforesting the littoral zone. Sapling growth variations were measured after two rounds of winter flooding. Dominant influence factors were determined by redundancy analysis. Herb community similarities between the experimental afforested areas and nearby control areas were assessed to detect the ecosystem influence of the experimental afforestation. 94.5% of saplings planted at elevations above 168 m survived. All measured growth indices (tree height, diameter at breast height, crown width and foliage density) decreased as the flood depth increased. Completely submerged saplings had a mean dieback height of -0.65 m. Greater initial foliage density led to increased tree height and stem diameter. Shannon-Wiener indices were not significantly different between plots in experimental and control areas, but the low similarity of herb communities between experimental and control areas (0.242 on average) suggested that afforestation would enrich plant community structure and improve littoral zone ecosystem stability. Because littoral zone afforestation provides several ecosystem services (habitat, carbon sink, water purification and landscaping), it is a promising revegetation model for the TGR.

Mulberry trees conserved soil and protected water quality in the riparian zone of the Three Gorges Reservoir, China

Chinas Sloping Land Conversion Program (SLCP) was designed to restore perennial plant cover on sloping land in western China, in part to protect the Three Gorges Reservoir (TGR). In this study, we examined use of white mulberry (Morus alba L.) in the SLCP to protect water quality and conserve soil. We established nine runoff monitoring plots divided among three categories (vegetable farming, fallow control, and mulberry plantation) on a bank of the Liangtan River situated at the western margin of the TGR. The land had been used previously by farmers for growing vegetables. We found that soil loss and surface water runoff were lowest in the mulberry plots and highest in the vegetable plots. We used inductively coupled plasma atomic emission spectroscopy (ICP-AES) to assess the concentration of selected heavy metal pollution indicators (Zn, Hg, As, Ni, Pb, Cr, Cd, and Cu) in the monitoring plot soils at the beginning of the experiment in May 2009. The heavy metals were assessed again at the end of the experiment in October 2012, and we found that the concentrations of these pollutants had been reduced in all fallow and mulberry plots, and to the greatest extent in the mulberry plots. We found that levels of Hg, Pb, and Cu increased in the vegetable plots. For these reasons, we conclude that riparian mulberry plantations are useful for reducing rapid runoff of storm water, conserving soil, and sequestering heavy metal pollutants in the TGR region.