Stem Branches Research Articles

Mental Health Literacy of University Students in Vietnam and Cambodia

Mental health literacy (MHL) refers to knowledge and attitudes that shape the recognition, management, and prevention of mental disorders. While the topic has been exhaustively researched in Western countries, research from Southeast Asia still is limited. Previous studies in this field showed a moderate recognition of mental disorders, a high prevalence of stigmatizing attitudes and a low willingness to seek professional help among Southeastern-Asian populations. This study explored the level of MHL among university students from different parts of Vietnam and Cambodia. Correlations with influencing factors (gender, age, study year, educational attainment of the parents, urban/rural origin, ethnicity, personal experiences with mental disorders) were also explored. An online survey, using a 30-item Vietnamese version of the Mental Health Literacy Scale (MHLS), was conducted at six university sites in Vietnam and Cambodia. Data of 1032 students from different study branches were included. The MHL of Vietnamese and Cambodian university students was lower, compared to samples from Australia or the UK. Females and students with a personal experience of mental disorders (self or family) showed a significantly higher MHL. No differences in MHL were found between students from different socioeconomic backgrounds (professional attainment of parents, urban/rural origin). Findings on the influence of ethnicity were inconclusive. MHL needs to be improved among the university students of Vietnam and Cambodia. Mental health promotion should specifically target male students, students from STEM branches, and international students.

Growth of Bush Pepper Seedlings of Different Sources of Cuttings Grown on Various Growing Media Formulas

Pepper grows creepingly following the growth of its climbing plants, making it difficult to maintain and harvest. Therefore, bush pepper cultivation was developed by replacing climbing trees with 1.5 m high concrete. However, seedlings that can grow into bush pepper are cuttings from fruit branches and primary branches, which are difficult to grow because the nodes of these branches do not have root primordia. This study aimed to obtain cuttings that can grow into bush pepper on the most superior growing media. The experiment was arranged using a completely randomized design (CRD) with two treatment factors, namely formulas of growth media (M1= soil + organic fertilizer + husk; M2= soil + organic fertilizer + compost; M3= soil + organic fertilizer + husk ash; and M4= soil + organic fertilizer + moss) and sources of cuttings (S1= climbing stem; S2= axillary branch; S3= fruit branch; and S4= primary branch with one main stem node). Based on the growth percentage of fruit branches and primary branches in the seedlings, cuttings from climbing stem and axillary branches were not able to grow into bush pepper, because fruit and primary branches only grew less than 5% in all media formulas. Cuttings from fruit branches and primary branches affect the formation of bush pepper with an average percentage of growth of fruit branches and primary branches of more than 95% on M2 and M3 media. Growth of buds, leaves and roots of cuttings from climbing stem and axillary branch was significantly better than cuttings from fruit branches and primary branches.

Estimation of Larch Growth at the Stem, Crown, and Branch Levels Using Ground-Based LiDAR Point Cloud

Tree growth is an important indicator of forest health and can reflect changes in forest structure. Traditional tree growth estimates use easy-to-measure parameters, including tree height, diameter at breast height, and crown diameter, obtained via forest in situ measurements, which are labor intensive and time consuming. Some new technologies measure the diameter of trees at different positions to monitor the growth trend of trees, but it is difficult to take into account the growth changes at different tree levels. The combination of terrestrial laser scanning and quantitative structure modeling can accurately estimate tree structural parameters nondestructively and has the potential to estimate tree growth from different tree levels. In this context, this paper estimates tree growth from stem-, crown-, and branch-level attributes observed by terrestrial laser scanning. Specifically, tree height, diameter at breast height, stem volume, crown diameter, crown volume, and first-order branch volume were used to estimate the growth of 55-year-old larch trees in Saihanba of China, at the stem, crown, and branch levels. The experimental results showed that tree growth is mainly reflected in the growth of the crown, i.e., the growth of branches. Compared to one-dimensional parameter growth (tree height, diameter at breast height, or crown diameter), three-dimensional parameter growth (crown, stem, and first-order branch volumes) was more obvious, in which the absolute growth of the first-order branch volume is close to the stem volume. Thus, it is necessary to estimate tree growth at different levels for accurate forest inventory.

Phenotypic diversity of agromorphological characteristics of quinoa (Chenopodium quinoa Willd.) germplasm in Colombia

Chenopodium quinoa Willd. is an Andean crop with great nutritional value, economic potential, and a broad genetic and phenotypic diversity with adaptation to different conditions. In Colombia, C. quinoa is cultivated mainly in Cundinamarca, Nariño and Boyacá, where studies have been conducted to characterize the germplasm and lack of seed materials, some challenges for the quinoa crop. This work assessed agromorphological characteristics of 50 quinoa genotypes from the germplasm collection of Boyacá the using a completely randomized design on the farm in Tunja. The multivariate analysis followed by a clustering approach were conducted on agromorphological descriptors, in which 16 were qualitative descriptors (e.g, panicle shape, episperm color, leaf shape) and five quantitative descriptors (e.g, plant height, panicle number). The results showed that higher coefficients of variation were found in characteristics associated to yield. The principal component analysis (PCA) of the quantitative variables showed that the first two components explained 88 % of the total variation with the characteristics of plant height, length, diameter, and panicle number showing the highest variability. The quantitative characteristic clusters comprised length and diameter panicle, weight 1,000 seeds, and plant height, while the qualitative characteristic clusters comprised stem shape, branching habit, panicle shape, and color of the axils. The factorial analysis of mixed data discriminated the materials with outstanding morphoagronomic characteristics. Agromorphological characterization revealed a broad variability, which should be conserved and used in genetic improvement programs of C. quinoa.

Adaptation of rapid multiplication method: cassava stem and root yield at different spacings and transplanting seasons.

This study aimed to assess cassava root and stem yield at different spacings and four transplanting seasons of seedlings produced by an adaptation of the rapid multiplication method. The experimental design was a randomized block design with three replications in a factorial (4 × 5) arranged in strips. Treatments consisted of the combinations of growing seasons (November 9 and 24 and December 3 and 26) and spacings (0.6 × 0.6, 0.8 × 0.8, 0.8 × 0.6, 1.0 × 0.6, and 1.0 × 0.8 m). The percentage of survival, main stem branching height, number of branches, base, middle, and upper diameter, mean diameter, stem length, number of buds per stem and hectare, root length and diameter, root fresh matter per plant and hectare, and number of roots per plant were measured at harvest. Seedling transplanting performed up to November 24 favored the expression of stem and root yield. The spacing of 1.0 × 0.6 m was the most suitable for stem yield traits.

The Inducible Accumulation of Cell Wall-Bound p-Hydroxybenzoates Is Involved in the Regulation of Gravitropic Response of Poplar.

Lignin in Populus species is acylated with p-hydroxybenzoate. Monolignol p-hydroxybenzoyltransferase 1 (PHBMT1) mediates p-hydroxybenzoylation of sinapyl alcohol, eventually leading to the modification of syringyl lignin subunits. Angiosperm trees upon gravistimulation undergo the re-orientation of their growth along with the production of specialized secondary xylem, i.e., tension wood (TW), that generates tensile force to pull the inclined stem or leaning branch upward. Sporadic evidence suggests that angiosperm TW contains relatively a high percentage of syringyl lignin and lignin-bound p-hydroxybenzoate. However, whether such lignin modification plays a role in gravitropic response remains unclear. By imposing mechanical bending and/or gravitropic stimuli to the hybrid aspens in the wild type (WT), lignin p-hydroxybenzoate deficient, and p-hydroxybenzoate overproduction plants, we examined the responses of plants to gravitropic/mechanical stress and their cell wall composition changes. We revealed that mechanical bending or gravitropic stimulation not only induced the overproduction of crystalline cellulose fibers and increased the relative abundance of syringyl lignin, but also significantly induced the expression of PHBMT1 and the increased accumulation of p-hydroxybenzoates in TW. Furthermore, we found that although disturbing lignin-bound p-hydroxybenzoate accumulation in the PHBMT1 knockout and overexpression (OE) poplars did not affect the major chemical composition shifts of the cell walls in their TW as occurred in the WT plants, depletion of p-hydroxybenzoates intensified the gravitropic curving of the plantlets in response to gravistimulation, evident with the enhanced stem secant bending angle. By contrast, hyperaccumulation of p-hydroxybenzoates mitigated gravitropic response. These data suggest that PHBMT1-mediated lignin modification is involved in the regulation of poplar gravitropic response and, likely by compromising gravitropism and/or enhancing autotropism, negatively coordinates the action of TW cellulose fibers to control the poplar wood deformation and plant growth.

GERMINATION OF PORANG (Amorphophalus muelleri) FROM DIFFERENT BULBIL TO VARIOUS PLANTING MEDIA

Porang plant is atubers that havevarious benefits. Porang cultivation needs intensive management through cultivation efforts which of course must be supported by the availability of seeds. Therefore, it is necessary to procure porang seeds from vegetative (tubers) and generative (stem bulbil and branch bulbil). This study aims to obtain the best growing media for porang germination from various types of bulbil. The method used in this study was a factorial randomized block design. The way of working in this research is: Preparation of Seedling Media, Preparation of planting material (Bulbil), Seeding, Maintenance (including watering and weeding). The results showed that there was no significant interaction between the planting medium and the type of bulbil, the media had no significant effect on all observed variables, while the bulbil had a significant effect on the percentage of germination growth, stem height, and number of leaves. The best type of bulbil for breeding is stem bulbil which is superior to the variables of plumule emergence time, petiole length, stem height, and number of leaves compared to branch bulbil. Meanwhile, the best growing media in porang nurseries was a mixture of 50% husk charcoal + 50% sawdust on the variables when the plumule appeared, the percentage of germination, petiole length and stem height. The appearance of bulbil from stems on a mixture of 50% husk charcoal + 50% sawdust media, namely the time of emergence of plumules (5.61 days), percentage of sprouting (86.67%), petiole length (8.72 cm), height stems (31.11 cm) and number of leaves (7.72 strands).

Individual and Interactive Temporal Implications of UV-B Radiation and Elevated CO2 on the Morphology of Basil (Ocimum basilicum L.)

Temporal and spatial variations in ozone levels and temporal changes in solar radiation greatly influence ultraviolet radiation incidence to crops throughout their growth, yet the interactive effects of CO2 and UV-B radiation on Basil production under sunlight environmental conditions has not been studied. Basil ‘Genovese’ plants grown under sunlit plant growth chambers were subjected to a combination of supplemental UV-B (0 and 10 kJ m−2d−1) and ambient (420 ppm) and elevated (720 ppm) CO2 treatments for 38 days after 14 days of germination. UV-B radiation treatments caused a decrease in basil stem branching, fresh mass, and stem dry mass under both CO2 treatments when harvested after 17 and 38 days of treatment. There was also an increase in basil leaf surface wax under UV-B (10 kJ m−2d−1) treatment compared to controls (0 kJ m−2d−1). Elevated CO2 treatments caused a decrease in morphological features, including specific leaf area and fresh mass. Interactive effects between UV-B and CO2 treatments existed for some morphological features, including plant height, root surface area, and average root diameter. Understanding the impacts that CO2 and UV-B radiation treatments have on basilcan improve existing varieties for increased tolerance while simultaneously improving yield, plant morphology, and physiology.

Biomass Production Assessment in a Protected Area of Dry Tropical forest Ecosystem of India: A Field to Satellite Observation Approach

In recent decades, degradation and loss of the world’s forest ecosystems have been key contributors to biodiversity loss and future climate change. This article analyzes plant diversity, biomass, carbon sequestration potential (CSP), and the net primary productivity (NPP) of four vegetation types viz., Dense mixed forest (DMF); Open mixed forest (OMF); Teak plantation (TP), and Sal mixed forest (SMF) in the dry tropical forest ecosystem of central India through remote sensing techniques together with physical ground observations during 2013–2018. The total C storage in trees varied from 16.02 to 47.15 Mg ha−1 in studied vegetation types with the highest in DMF and lowest in OMF. The total C storage in stem wood, branches, and foliage falls in the range of 52.93–78.30%, 9.49–22.99%, and 3.31–12.89% respectively. The total standing biomass varied from 83.77 to 111.21 Mg ha−1 and these variations are due to different vegetation types, with the highest in DMF followed by TP, SMF while the lowest was estimated in OMF. The net primary productivity (NPP) [aboveground (AG) + belowground (BG)] varied from 7.61 to 9.94 Mg ha−1 yr−1 with mean values of 8.74 Mg ha−1 yr−1 where AG shares a maximum contribution of 77.66%. The total biomass production was distributed from 64.09 to 82.91% in AG and 17.08–35.91% in BG components. The present study outlines that the studied forest ecosystem has the substantial potential of carbon sequestration and a great possibility of mitigating local and global climate change.

Participatory Selection of Amaranthus Genotypes in the KwaMbonambi Area, KwaZulu-Natal, South Africa

Participatory variety selection (PVS) is a process that tests promising genotypes in farmers’ fields through a close farmer–researcher collaboration approach, which enhances the acceptance of new varieties by farmers. However, limited studies have been conducted to select Amaranthus genotypes that have potential for future breeding programmes in South Africa. Therefore, this study was aimed at selecting Amaranthus genotype(s) that is/are preferred by farmers in northern KwaZulu-Natal, using the PVS approach. Seedlings of fifteen Amaranthus genotypes were each planted in separate 10 × 10 m plots. Fourteen local farmers managed these genotypes and also determined the preferred traits to be used to evaluate them. These traits were: mild taste; profuse stem branching; big and numerous leaves; soft texture; and longer shelf life. Plants at four months after transplant were then evaluated and ranked according to farmers’ preferred traits using score sheets designed on a four-point Likert scale or five-point hedonic scale. However, genotype ACAT seed fair had the best scoring for appealing taste and aroma, and profuse branching. The TOT 8789 genotype had the largest and softest leaves. Again, A. thunbergii had the most numerous leaves of them all. These genotypes are thus recommended for multi-environment testing, seed multiplication, genetic improvement, and promotion for cultivation in South Africa.

The Melastoma dodecandrum genome and the evolution of Myrtales

Melastomataceae has abundant morphological diversity with high economic and ornamental merit in Myrtales. The phylogenetic position of Myrtales is still contested. Here, we report the chromosome-level genome assembly of Melastoma dodecandrum in Melastomataceae. The assembled genome size is 299.81 Mb with a contig N50 value of 3.00 Mb. Genome evolution analysis indicated that M. dodecandrum, Eucalyptus grandis, and Punica granatum were clustered into a clade of Myrtales and formed a sister group with the ancestor of fabids and malvids. We found that M. dodecandrum experienced four whole-genome polyploidization events: the ancient event was shared with most eudicots, one event was shared with Myrtales, and the other two events were unique to M. dodecandrum. Moreover, we identified MADS-box genes and found that the AP1-like genes expanded, and AP3-like genes might have undergone subfunctionalization. The SUAR63-like genes and AG-like genes showed different expression patterns in stamens, which may be associated with heteranthery. In addition, we found that LAZY1-like genes were involved in the negative regulation of stem branching development, which may be related to its creeping features. Our study sheds new light on the evolution of Melastomataceae and Myrtales, which provides a comprehensive genetic resource for future research.

An optimized natural convection Y-shape-shifted heat sink design problem

An optimized design problem for a natural convection three-dimensional Y-shape-shifted heat sink is investigated numerically and experimentally in the present study. The software package CFD-ACE+ and the Levenberg-Marquardt method (LMM) are utilized as the numerical solution solver and design tool, respectively. The objective of this work is to design the optimal fin stem height, fin branch length, branching angle, and shift distance of the Y-shaped fin under fixed Y-shaped fin volume conditions to minimize the base plate temperature and enhance the cooling performance of the heat sink. The thermal radiation effect between the air and Y-shaped fin is considered in this work to improve the accuracy of the numerical solution of temperatures. The result indicates that in the optimized Y-shaped heat sink, the stem height and branching angle become shorter and larger, respectively, than those of the original design. When the shift distance is considered as a design variable, i.e., the optimized Y-shape-shifted heat sink with an up-up-up fin displacement arrangement, the chimney-flow effect due to the buoyant plume is much more pronounced than that of the original design, and a pair of longitudinal vortices also occur; therefore, better heat dissipation performance can be achieved. Experiments were performed on manufactured heat sinks to check the validity of the design results. The results indicated that the measured temperatures of the heat sinks are very close to the computed data since the maximum error between the computed and measured base temperatures is less than 0.81%. In addition, design B1 (a vertical heat sink) has the smallest thermal resistance Rth among all designs at 2.6% smaller than that of the original vertical heat sink, which confirms the validity of the present work in designing the optimal design of the Y-shape-shifted heat sink.

A NEW ANNUAL SPECIES OF CHAENACTIS (COMPOSITAE) FROM THE CENTRAL DESERT OF BAJA CALIFORNIA, MEXICO

A new yellow-flowered annual pincushion, Chaenactis kyhosii B.G.Baldwin, is described from the Central Desert of Baja California, Mexico. This desert taxon has been confused with C. glabriuscula DC. sensu lato (s. l.), a species complex of the California Floristic Province and desert periphery. Chaenactis kyhosii (2n = 5II) is evidently allopatric with C. glabriuscula s. l. (2n = 6II) and is distinct chromosomally. It differs morphologically from other yellow-flowered members of Chaenactis, including C. glabriuscula s. l., by the character-state combination of having non-glandular hairs sparse or lacking, main stem branches concentrated at or near base, leaves mostly basal or proximal on stems, leaf blades entire and filiform or once-pinnate with filiform lobes, peduncles and involucres densely glandular, corollas of marginal florets only slightly enlarged, cypselae sparsely white-strigose to ± glabrate, and pappi uniseriate, of four well-developed, generally unequal, and often obtuse scales. Chaenactis kyhosii is more closely related to the white-flowered, primarily desert-dwelling annual C. fremontii A.Gray, also with 2n = 5II, and the southern lineages of C. glabriuscula s. l. than to the northern lineages of C. glabriuscula s. l.

Vertical Canopy Profile and the Impact of Branches on Soybean Seed Composition.

Soybean [Glycine max (L.) Merr.] seeds are of global importance for human and animal nutrition due to their high protein and oil concentrations, and their complete amino acid (AA) and fatty acid (FA) profiles. However, a detailed description of seed composition at different canopy portions (i.e., main stem and branch nodes) is currently lacking in scientific literature. This study aims to (1) characterize seed yield and composition (protein, oil, AA, and FA) at the main stem (exploring a vertical canopy profile) and stem branches and (2) quantify the impact of canopy yield allocation on seed composition, focusing on branches as a potential contributor for higher yields. Four genotypes were field-grown during the 2018 and 2019 seasons, with seeds manually harvested from all the branches and three main stem segments (lower, middle, and upper). Seed samples were analyzed for seed yield (Mg/ha), seed size (mg/seed), protein and oil content (mg/seed) and their respective concentrations (g/kg), and AA and FA concentrations within protein and oil (g/100 g), herein called abundance. The upper main stem produced greater protein (25%) and oil (15%) content relative to the lower section; however, oil concentration increased from top to bottom while protein concentration followed opposite vertical gradient. Limiting AAs (lysine, cysteine, methionine, threonine, and tryptophan) were more abundant in the lower main stem, while the oleic/(linoleic + linolenic) ratio was greater in the upper segment. Overall, branches produced seeds with inferior nutritional quality than the main stem. However, the contribution of branches to yield (%) was positively related to limiting AA abundance and oil concentration across soybean genotypes. Future research studies should consider the morphological process of stem branching as a critical factor intimately involved with soybean seed composition across environments, genotypes, and management practices.

Genetic Variation and the Effect of Herbicide and Fertilization Treatments on Wood Quality Traits in Loblolly Pine

Abstract The effect of silvicultural treatments (herbicide, fertilization, herbicide + fertilization) and the interactions with genetic effects were investigated for wood quality traits in a 16-year-old loblolly pine (Pinus taeda L.) genetic test established in southwest Georgia, USA. Fertilizer and herbicide treatment combinations were applied multiple times to main plots containing 25 open-pollinated families as sub plots. Significant differences among treatments were found for all traits. Squared acoustic velocity, used as a surrogate for wood stiffness, was higher in herbicide-only plots compared with other treatments. Wood density was considerably lower in fertilization plots. A large proportion of variance observed for wood quality traits was explained by additive genetic effects, with individual-tree heritabilities ranging from 0.78 (ring 7–16 section wood density) to 0.28 (ring 2–6 section wood density). Corresponding family-mean heritability values were well over 0.86. Genotype-by-treatment interactions were nonsignificant for all traits, indicating no need to match families to silvicultural treatments. Wood quality traits had weak genetic correlations with growth and stem quality traits (stem slenderness, sweep, and branch angle) with a range of −0.33 to 0.43, suggesting that recurrent selection on growth or stem quality traits would not adversely affect wood quality in loblolly pine.

Effect of climate warming on seedling growth and biomass accumulation of Acacia modesta and Olea ferruginea in a subtropical scrub forest of Pakistan

ABSTRACT This study investigated the short-term impacts of projected climate warming on two dominant tree species of the Hayat-ul-Mir subtropical scrub forest of Pakistan. Seedlings of Acacia modesta and Olea ferruginea were exposed to ambient (To) and warming temperature (To + 2.3°C and To + 4.5°C) with control (M15%) and elevated (M20%) soil moisture in plant growth chamber for 90 days. To + 4.5°C induced detrimental effects on both species inhibiting seed germination and reducing their growth rate, biomass accumulation and allocation, however promoted development of root nodules (12 ± 4,0 nodules/root) in A. modesta. To + 2.3°C with M20% was beneficial for O. ferruginea with significant increase in stem height (4.8 ± 1.4 cm), elongated roots (31.2 ± 3.4 cm), branch development (9 ± 1.7), biomass accumulation (8.69 ± 0.4 g) and higher foliar nutrient concentration but for A. modesta it only promoted root elongation (16.5 ± 1.3 cm) and biomass accumulation in stem (1.05 ± 0.1 g) and foliage (0.08 ± 0.001 g). A. modesta grew better under To with significantly high germination and survival rate. A future 2.3°C warming could be ecologically significant to induce shifts in the structure and function of the Hayat-ul-Mir forest.

PHYSICAL QUALITY AND PRODUCTIVITY OF COCOA BEAN (Theobroma cacao L.) BASED ON CANOPY POSITION AND PLANT AGE

The research aimed to study the cocoa bean quality and productivity based on their position on canopy and different plant ages. This has been conducted at cocoa farming area at Wonggeduku Subdistrict, Konawe Regency, Southeast Sulawesi Province. These treatments were arranged based on the nested design in which the pod position on the canopy i.e. on main stem, primary and secondary branches, and nested to the plant ages i.e. 8,10, 12, and 14 years old were used. The observed variable were pod length, pod diameter, seed weight, seed number, and dry production per pod. The data gathered were analysed by analysis of variance and the difference between treatments were justified by Duncan’s Multiple Range Test at 95% significant level. To study the relationship between plant ages and pod position on canopy, the regression analysis was applied. Research result showed that there were interaction effect on pod position and ages on all variable observed. The best treatment on the main stem and primary branch at eight year age of the plant was on the length, diameter and weight of pods, seed number, and dry seed production per pod. KEY WORDS: Cocoa pod, plant age, pod position, production, quality

New petrified calamitaleans from the Permian of the Parnaíba Basin, central-north Brazil, part III, with some concerns regarding anatomical features of Paleozoic petrified sphenophytes

A new petrified calamitalean is described from the Permian Motuca Formation, Parnaíba Basin, central-north Brazil. In contrast to all other three-dimensionally preserved Brazilian species, it represents a semi-self-supporting woody plant characterized by a distinctive branch system and cellular anatomy. Arthropitys buritiranensis sp. nov. is proposed to accommodate the new material. The branch architecture is composed of at least three types of branches: (i) principal woody side branches, (ii) up to three secondary woody branches per node, scattered along the stem or the principal side branches, and (iii) 8–11 leafy twigs per whorl, at every third, rarely the second node, without secondary growth. The wood is segmented into fascicular wedges and interfascicular rays, clearly visible only within the inner wood of the stem and woody branches. The tracheid walls of the secondary xylem have exclusively scalariform pits. Ray parenchyma cells have pitted horizontal walls. The new calamitalean was part of the riparian vegetation of tree ferns, calamitaleans and gymnosperms recorded in a distal fluvial plain setting. The wood shows irregular growth interruptions and, therefore, points to a seasonally dry climate that shaped even low latitude paleofloras of tropical Pangaea.

Effects of above- and below-ground herbivore interactions on interspecific relationship between the invasive plant Alternanthera philoxeroides and its native congener Alternanthera sessilis

Biological invasion is a major threat to global biodiversity. The relative interspecific competition abilities of invasive species compared to those native species determine their invasion success. In this study, we examined the effects of the specialist leaf beetle Agasicles hygrophila and the nematode Meloidogyne incognita on the growth and interspecific relationship between the invasive plant Alternanthera philoxeroides and its native congener A. sessilis. Compared without herbivory, nematode herbivory alone significantly reduced shoot height of A. sessilis by 28.1%, but conversely significantly increased the shoot height of A. philoxeroides by 52.8% and aboveground biomass of A. sessilis by 63.7%. Beetle herbivory alone significantly reduced shoot height of A. sessilis by 40.7%, but did not affect that of A. philoxeroides. The combination of beetle and nematode herbivory significantly reduced shoot height of A. sessilis by 35.3% as well as the belowground biomass of A. philoxeroides by 62.2%, but significantly increased the aboveground biomass of A. sessilis by 69.1%. Herbivore stress did not affect stem diameter, branch number, and root length of both species. The relative neighbor effect index (RNE) of the two species without herbivory were positive, and the RNE value of A. philoxeroides was 21.3% higher than that of A. sessilis. However, the RNE values of A. philoxeroides were negative under all above- and below-ground herbivory treatments. The RNE values of A. sessilis were positive under the beetle or the nematode herbivory alone and negative under the beetle + nematode herbivory combination. These results indicated that above- and below-ground herbivore interactions could change the interspecific relationship between the two species, and in turn might accelerate the invasion of A. philoxeroides.

Hydraulic architecture and internal water storage of Japanese cypress using measurements of sap flow and water potential

AbstractWe studied the hydraulic architecture and internal water storage of a 60‐year‐old Japanese cypress tree (Chamaecyparis obtusa) by concurrent measurements of sap flow rates (u) and in situ water potential (Ψ) of the soil, stem, branches and leaves along the hydraulic system over a year. Distal organs such as lateral branches and leaves showed lower Ψ than that of stem throughout the year, and the lowest hydraulic conductance (K) was shown between the upper stem and lateral branches. Compared to water flow in the upper stem, latent heat flux (lE) began increasing at approximately 1 h earlier in the morning and ceased at 0.5–1 h earlier in the evening, coinciding with variations in solar radiation and vapour pressure deficits. We also observed a distinct time lag (~2 h) in u and Ψ between the basal and upper portions of the stem in the morning and evening. Although lE, u and Ψ peaked near noon in both the basal and upper portions of the stem, the two parameters exhibited different diurnal curves. These differences suggest that water stored in the stem and foliage is withdrawn in the morning, prior to water uptake from the soil, whereas differences in the evening point to recharge of it. Although the contribution of stem water storage was approximately 5% of daily transpiration, it is possible that hydraulic architecture of C. obtusa maintains the water transport efficiency on the outermost layer of the canopy where high transpiration demand.