Winter Shoots Research Articles

Integrative analysis of metabolome and transcriptome reveals the different metabolite biosynthesis profiles related to palatability in winter and spring shoot in moso bamboo

Moso bamboo winter shoot has good taste and rich nutritional value. To reveal the causes and regulatory mechanism of palatability deterioration from winter to spring shoot, a conjoint analysis of metabolome and transcriptome was conducted on winter and spring shoots of moso bamboo. Totally 909 metabolites were characterized for the first time. The significant increase of hydrolyzed tannin content intensified the bitterness of spring shoot, which was positively regulated by key metabolite (gallic acid) and genes (DAHPS, DHQS, DHQ, SDH) in the biosynthesis pathway of hydrolyzed tannin. The accumulation of lignified components enhanced the roughness of spring shoot, which was closely connected with the significant changes of important metabolites (cinnamic acid, ferulic acid, UDP-glucose and UDP-xylose) and up-regulation of most enzyme genes involved in the biosynthesis pathways of lignin, cellulose and hemicellulose. The present study provides theoretical support for understanding palatability transition and directional improvement of edible quality of moso bamboo shoots.

Morphology of wintering shoots of a rare species Exochorda serratifolia S. Moore in Primorsky Krai

The paper studies the morphology of winter shoots of the rare species Exochorda serratifolia S. Moore (Rosaceae Juss.) included in the Red Book of Primorsky Krai (Russian Federation) in the natural population (Khankaisky district of Primorsky Krai) and in culture (the arboretum of the Mountain Taiga Station of the Far Eastern Branch of the Russian Academy of Sciences) during 2020-2021. The studied morphological features (linear dimensions of the stem, buds and leaf scars, the number of metamers, bud scales, etc.) vary slightly. A number of morphological characteristics of the buds of Exochorda serratifolia – polyscaly, type of budding, the presence of a waxy coating are adaptive features to temperate continental climatic conditions. The obtained data on the morphology of overwintering shoots of Exochorda serratifolia can be used as additional diagnostic features for identification of the plant in a leafless state.

Restoring a keystone tree species for the future: American chestnut assisted migration plantings in an adaptive silviculture experiment

Species ranges are forecast to change in response to warming temperatures and altered precipitation patterns, yet tree migration rates fail to track the pace of climate change. In anticipation of these changes, various forest adaptation management strategies have been broadly proposed, including intentionally modifying species composition via assisted migration of future climate adapted species. Despite the potential utility of these adaptation measures, practical evaluations are limited, particularly those applied to meet other ecological objectives such as supporting vulnerable, underrepresented, or degraded populations of foundational species. In this study, we examined the 4-year seedling survival and morpho-physiological response of American chestnut (Castanea dentata (Marsh.) Borkh.; n = 959 seeds sown), a functionally extirpated species. American chestnuts were grown within sixteen replicated 0.1 and 0.4 ha harvest gaps as part of a 160 ha co-developed (manager-scientist designed), operational-scale silvicultural trial (conditions of sufficient scope to be representative of commercial forest operations) in a northern-hardwood forest in the northeastern US. Chestnut restoration and migration potential (e.g., survival, absolute and relative growth rates, photosynthetic capacity) was assessed against the biophysical controls exerted on seedlings (e.g., understory competition, injury associated with browse and extreme cold winter temperatures) and in comparison to seedlings planted from eight other tree species (n = 480 planted per species) identified for assisted migration. Our results show the performance of American chestnut seedlings is controlled by the strength of local competition (odds of survival increased 2.6 times between four understory competition classes, p < 0.001) and cumulative winter shoot injury (relative growth in aboveground biomass adjusted for injury R2 = -0.85, p < 0.001) associated with cold intolerance likely linked to northward movement of chestnut seedlings transferred outside of their parental range. Still, the combined survival-growth response for American chestnuts ranked among the highest (2nd out of 6 possible rankings) relative to the other species tested, and even outperformed other comparable assisted migration species introduced from outside of their parental range. The implications of these findings highlight the potential for American chestnut plantings to be incorporated within both restoration and broader climate adaptation frameworks. Despite these promising outcomes, important biophysical (e.g., vegetative competition, harvest treatment, and variability in insulative snowpack) and climatic barriers for the reestablishment of this species remain. Given the paucity of reproductively viable American chestnuts or disease resistant breeding programs along northern range limits, this may generate a reliance on plant material obtained from outside of historically recognized safe transfer distances; however, increasingly shifting climate and species ranges may lead to better climate matches in the long term. Nevertheless, the broader applicability of this work illustrates the potential for cultural and ecological keystone species restoration efforts to be incorporated within climate adaptation frameworks to assist in the establishment of compositionally diverse and future climate-adapted forests.

Total and Mitochondrial Transcriptomic and Proteomic Insights into Regulation of Bioenergetic Processes for Shoot Fast-Growth Initiation in Moso Bamboo.

As a fast-growing, woody grass plant, Moso bamboo (Phyllostachys edulis) can supply edible shoots, building materials, fibrous raw material, raw materials for crafts and furniture and so on within a relatively short time. Rapid growth of Moso bamboo occurs after the young bamboo shoots are covered with a shell and emerge from the ground. However, the molecular reactions of bioenergetic processes essential for fast growth remain undefined. Herein, total and mitochondrial transcriptomes and proteomes were compared between spring and winter shoots. Numerous key genes and proteins responsible for energy metabolism were significantly upregulated in spring shoots, including those involved in starch and sucrose catabolism, glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle and oxidative phosphorylation. Accordingly, significant decreases in starch and soluble sugar, higher ATP content and higher rates of respiration and glycolysis were identified in spring shoots. Further, the upregulated genes and proteins related to mitochondrial fission significantly increased the number of mitochondria, indirectly promoting intracellular energy metabolism. Moreover, enhanced alternate-oxidase and uncoupled-protein pathways in winter shoots showed that an efficient energy-dissipating system was important for winter shoots to adapt to the low-temperature environment. Heterologous expression of PeAOX1b in Arabidopsis significantly affected seedling growth and enhanced cold-stress tolerance. Overall, this study highlights the power of comparing total and mitochondrial omics and integrating physiochemical data to understand how bamboo initiates fast growth through modulating bioenergetic processes.

Phenology, cold injury and growth of American chestnut in a Range-Wide provenance test

The primary factor limiting the distribution and growth of American chestnut (Castanea dentata (Marsh.) Borkh.) in eastern North America is tolerance to chestnut blight that is caused by the introduced fungal pathogen Cryphonectria parasitica (Murr.) Barr. However, a better understanding of how genetics and the environment influence American chestnut physiology and growth will also be needed to guide restoration as blight-tolerant growing stock becomes available. Here we describe patterns of phenology, cold injury and radial growth for American chestnut from 13 seed sources that represent three temperature zones (warm, moderate and cold) grown together in a unique provenance test in Vermont, USA. Temperature zones were established using data on the mean minimum winter temperatures over 10–30 years for weather stations nearest seed source locations; these averages were −5 °C and above for the warm temperature zone, −5 to −10 °C for the moderate temperature zone, and below −10 °C for the cold temperature zone. There was a consistent trend for trees from the warm temperature zone to break bud and leaf out earlier, and experience greater spring leaf frost damage and shoot winter injury than trees from other temperature zones. After initial establishment, woody growth (approximately 6 years of ring counts) was robust and tended to be greatest among moderate temperature zone sources and lowest for cold zone sources. Especially for trees from the warm zone, earlier budbreak was associated with greater growth. Foliar frost injury was not associated with altered growth, whereas winter shoot damage was associated with lower growth – especially following significant shoot loss. Even though warm temperature zone sources experienced more winter injury than trees from cold temperature zones, the growth of cold temperature zone sources tended to underperform that for warm and moderate zone sources – this suggests that, at least for the limited time that we evaluated growth, greater protection from the cold may come at the cost of greater growth potential. Although American chestnut is considered to be a relatively drought-tolerant species and growth was assessed during a period of historically high precipitation, higher moisture availability the year before, and occasionally during, the year of ring formation was broadly associated with greater growth across the temperature zones. Despite the negative influences of winter shoot injury on growth, the overall productivity of trees was exceptional, even at the northern edge of the species’ range provided that moisture availability was adequate.

Do trait responses to simulated browsing in Quercus robur saplings affect their attractiveness to Capreolus capreolus the following year?

With the rise of large herbivore populations in most northern hemisphere forests, browsing is becoming an increasingly important driver of forest regeneration dynamics. Among other processes affecting the regeneration, the concept of plant-herbivore feedback loops holds that browsed saplings are more subject to subsequent herbivory. This phenomenon is interpreted as a consequence of compensatory growth following browsing since fast growth is generally associated with higher digestibility and lower defense against herbivores. However, studies linking browsing-induced trait variations to subsequent attractiveness to herbivores are still lacking, especially in the forest context. In this study, we experimentally examine the existence of a feedback loop between oak ( Quercus robur L.) and roe deer ( Capreolus capreolus ) and investigate its underlying morphological and chemical traits. We simulated single and repeated roe deer browsing on nursery-grown oak saplings and measured the changes in sapling height growth, lateral branching, leaf traits and winter shoot traits over two years. We conducted winter feeding trials with tame roe deer one year after the first treatment to test the effect of simulated browsing on sapling attractiveness. Simulated browsing reduced sapling height growth but had no effect on branching. Simulated browsing had no effect on leaf traits after half a year, but decreased the phenolic content and increased the fiber content of winter shoots the following winter. Contrary to our predictions, roe deer preferentially browsed control saplings over saplings previously browsed. After two years, repeated browsing promoted fast carbon acquisition leaf traits (high chlorophyll, high specific leaf area and low fiber content), reduced leaf phenolic content and increased leaf digestibility. We showed that a reduction in 1-year-old oak sapling height growth following browsing, combined with increased structural defense at the expense of chemical defense in winter shoots the following winter, was correlated with reduced browsing pressure, thereby challenging the feedback loop hypothesis. However, we also demonstrated that repeated browsing promoted fast carbon acquisition leaf traits in 2.5-year-old saplings, which tend to support the existence of a feedback loop on older and more intensively browsed saplings. As such, our study provides empirical evidence that morphological and physiological trait responses to browsing influence oak sapling attractiveness, but that the direction and magnitude of this effect depend on the ontogenic stage of the sapling and on the number of browsing events. • We examine the morphological and chemical response of oak saplings to browsing. • Browsing reduces sapling height growth and modifies shoots chemical composition. • We show with feeding trials that roe deer prefers unbrowsed saplings. • Oak trait responses to browsing decrease the probability of subsequent herbivory.

Comparative Multi-Omics of Tender Shoots from a Novel Evergrowing Tea Cultivar Provide Insight into the Winter Adaptation Mechanism.

Tea (Camellia sinensis [L.] O. Kuntze) tree is a perennial plant in which winter dormancy is an important biological adaptation to environmental changes. We discovered and reported a novel tea tree cultivar that can generate tender shoots in winter several years ago, but the molecular mechanism for this unique phenotype remains unknown . Here, we conducted comparative transcriptomics, proteomics and metabolomics along with phytohormone quantitation between the winter and spring tender shoots to investigate the physiological basis and putative regulatory mechanisms of its evergrowing character during winter. Our multi-omics study has led to the following findings. Gibberellin (GA) levels and key enzymes for GA biosynthesis and the signal transduction pathway were increased in the winter shoots, causing the ABA/GA content ratio to decrease, which might play a key regulatory role in maintaining normal growth during winter. The abundance of proteins, genes and metabolites involved in energy metabolism was all increased in winter shoots, indicating that energy is critical for continuous growth under the relatively weak-light and low-temperature environment. Abiotic resistance-related proteins and free amino acids were also increased in abundance in the winter shoots, which possibly represents an adaptation response to winter conditions. These results allowed us to hypothesize a novel molecular mechanism of adaptation for this unique tender shoot evergrowing in winter.

Changes in the distribution of endogenous hormones in Phyllostachys edulis 'Pachyloen' during bamboo shooting.

In this study, we investigated the changes in the distribution and regulation of endogenous hormones in Phyllostachys edulis ‘Pachyloen’ during bamboo shooting. Enzyme-linked immunosorbent assay was used to measure the mass fractions of indole-3-acetic acid (IAA), gibberellic acid (GA), zeatin riboside (ZR), and abscisic acid (ABA) in rhizomes, shoots, and maternal bamboo organs during shoot sprouting, shoot growth, and new-bamboo formation. Measurements were compared among bamboo parts and developmental periods. The overall mass fractions of IAA and ABA were significantly higher than those of ZR and GA, driven by differences among bamboo parts and developmental periods. The abundance of each endogenous hormone varied among bamboo parts and developmental periods. During bamboo shooting, ABA had the highest mass fraction in all bamboo parts sampled, followed by IAA, GA, and ZR. Among bamboo parts, rhizomes had more IAA, ZR, and GA than the other parts, but significantly less ABA. Winter shoots had higher ZR: IAA and GA: IAA ratios than rhizomes and maternal bamboo organs. During shoot growth, ABA was the most abundant hormone in rhizomes and maternal bamboo organs, followed by IAA, ZR, and GA. In contrast, IAA was the most abundant hormone in spring shoots, followed by ABA, ZR, and GA. Maternal bamboo organs had a significantly higher ZR: GA ratio, and significantly lower IAA: ABA, ZR: ABA, and GA: ABA ratios than rhizomes. Spring shoots had significantly higher IAA: ABA, ZR: ABA, and GA: ABA ratios than rhizomes and maternal bamboo organs; significantly higher ZR mass fractions, and ZR: GA and ZR: IAA ratios and significantly lower ABA mass fractions than rhizomes; and significantly higher GA: IAA ratio than maternal bamboo organs. During new-bamboo formation, ABA was the most abundant hormone in rhizomes, winter shoots, and maternal bamboo organs, followed by IAA, ZR, and GA. Maternal bamboo organs had significantly lower IAA mass fractions and significantly higher ABA mass fractions than rhizomes and new bamboo tissue. IAA and ABA abundances exhibited an inverse relationship in rhizomes and maternal bamboo organs. GA: ABA and GA: IAA ratios decreased gradually and other hormone ratios exhibited parabolic trends over the bamboo-shooting period, with the highest ratios observed in new bamboo tissues. Overall, the coordination or antagonism among endogenous hormones plays a key regulatory role in bamboo shoot growth. The formation of thick walls in P. edulis ‘Pachyloen’, one of its major traits, may be partially attributed to the relatively high IAA and ZR and low GA mass fractions.

Identifying species and hybrids in the genus juglans by biochemical profiling of bark

The biochemical profiling of flavonoids in the bark of winter shoots was conducted with the purpose of ecological management of implicit environmental threats of invasions of the species of the genus Juglans and their hybrids under naturalization. Six species of Juglans, introduced into forests and parks of Kyiv, were studied, namely, J. ailantifolia Carriere, J. cinerea L., J. mandshurica Maxim., J. nigra L., J. regia L., and J. subcordiformis Dode, cultivar J. regia var. maxima DC. ′Dessert′ and four probable hybrids (♀J. subcordiformis × ♂J. ailantifolia; ♀J. nigra × ♂J. mandshurica; ♀J. cinerea × ♂J. regia and ♀J. regia × ♂J. mandshurica). Due to the targeted introduction of different duration, the invasive species are at the beginning stage of forming their populations, sometimes amounting to naturalization. The species-wise specificity of introduced representatives of different ages (from one-year-old seedlings to generative trees), belonging to the genus Juglans, was determined. J. regia and J. nigra are the richest in the content of secondary metabolites; J. cinerea and J. mandshurica have a medium level, and J. ailantifolia and J. subcordiformis-a low level. On the contrary, the representatives of J. ailantifolia and J. subcordiformis are the most diverse in the content of secondary metabolites. Hybrid forms are notable for the decreased content of flavonoids, which may have a considerable impact on their individual resistance and ecological flexibility. The latter circumstance should be considered in the ecological management of walnut plantings in Kyiv. The results of biochemical profiling of secondary metabolites from winter shoot bark demonstrated that six investigated species belonged to four sections: Juglans, Cardiocaryon, Rhysocaryon, and Trachycaryon. The hybrids were usually grouped by the sections, represented by the paternal component in the hybrid pair. However, recent results of complete genome sequencing were used by the scientists to prove a relevant evolutionary role of the phenomenon of hybridization in the genus Juglans between the species, separated in the modern areas between the American and Eurasian continents, in particular, the ones, introduced into the Kyiv plantings. The revealed genomic mosaicism forms a new impression about phylogenetic relations within the genus. The possibility of using the biochemical profiling of winter shoot bark for some utilitarian needs (including the determination of the content of useful biologically active substances and detecting the advantages of hybrids by their performance features) is discussed

A Comparative Study between Evergreen and Deciduous Daylily Species Reveals the Potential Contributions of Winter Shoot Growth and Leaf Freezing Tolerance to Foliar Habits

Evergreen ornamental plants can supply year-round aesthetic value and strong ecological benefits in comparison to deciduous species. However, less attention has been paid to the cause of foliar habits, especially in herbaceous perennials. A comparative study on evergreen and deciduous species with close relationships could help to uncover the factors that determine foliar habits when sibling mutants are absent. Three independent experiments were conducted in the present study. Experiment 1 was focused on the changes in the percentage of green leaves (PGL) between evergreen daylilies (Hemerocallis aurantiaca Baker) and the deciduous species (Hemerocallis fulva L.). The results showed that their foliar habits were consistent with those of previous reports but could be influenced dramatically by the air temperature. The leaf freezing tolerance (LFT) and relevant morphological, physiological and biochemical variations in leaf tissues in addition to the shoot growth status were determined during Experiments 2 and 3 when comparing natural cold acclimation to de-acclimation. Correlation analyses between the PGL and other indices indicated that the winter shoot growth probably maintained the green leaves of the evergreen daylilies, while a strong LFT might facilitate the defoliation of deciduous species. Furthermore, the dormant deciduous daylily is more freezing-tolerant than the ever-growing evergreen species. This study also possesses practical value for plants with variant green periods in landscaping.

Особливості формувань популяції совки озимої Agrotis segetum Schiff. у польових сівозмінах Лісостепу України

Особливості формувань популяції совки озимої Agrotis segetum Schiff. у польових сівозмінах Лісостепу України

Comparative proteomics reveals the physiological differences between winter tender shoots and spring tender shoots of a novel tea (Camellia sinensis L.) cultivar evergrowing in winter

BackgroundA recently discovered tea [Camellia sinensis (L.) O. Kuntze] cultivar can generate tender shoots in winter. We performed comparative proteomics to analyze the differentially accumulated proteins between winter and spring tender shoots of this clonal cultivar to reveal the physiological basis of its evergrowing character during winter.ResultsWe extracted proteins from the winter and spring tender shoots (newly formed two leaves and a bud) of the evergrowing tea cultivar “Dongcha11” respectively. Thirty-three differentially accumulated high-confidence proteins were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF / TOF MS). Among these, 24 proteins had increased abundance while nine showed were decreased abundance in winter tender shoots as compared with the spring tender shoots. We categorized the differentially accumulated proteins into eight critical biological processes based on protein function annotation including photosynthesis, cell structure, protein synthesis & destination, transporters, metabolism of sugars and polysaccharides, secondary metabolism, disease/defense and proteins with unknown functions. Proteins with increased abundance in winter tender shoots were mainly related to the processes of photosynthesis, cytoskeleton and protein synthesis, whereas those with decreased abundance were correlated to metabolism and the secondary metabolism of polyphenolic flavonoids. Biochemical analysis showed that the total contents of soluble sugar and amino acid were higher in winter tender shoots while tea polyphenols were lower as compared with spring tender shoots.ConclusionsOur study suggested that the simultaneous increase in the abundance of photosynthesis-related proteins rubisco, plastocyanin, and ATP synthase delta chain, metabolism-related proteins eIF4 and protease subunits, and the cytoskeleton-structure associated proteins phosphatidylinositol transfer protein and profilin may be because of the adaptation of the evergrowing tea cultivar “Dongcha11” to low temperature and light conditions. Histone H4, Histone H2A.1, putative In2.1 protein and protein lin-28 homologs may also regulate the development of winter shoots and their response to adverse conditions.

Chloride and carbonate salinity tolerance in Mimusops zeyheri seedlings during summer and winter shoot flushes

ABSTRACTShoot flushes alternate with root flushes and the evergreen red milkwood (Mimusops zeyheri Sond.) fruit tree has winter (May–July) and summer (October-December) shoot flushes in southern hemisphere. Fruit of this plant contain high vitamin C and the tree is being researched and bred for arid inland southern Africa regions. Climate change predictions suggested that by 2030 the regions would experience high temperatures (>45°C), recurrent floods and repeated droughts, which are associated with increased salinity challenges. The objective of this study was to determine the degree of salt tolerance in M. zeyheri seedlings to chloride and carbonate salinity during summer and winter shoot flushes under microplot conditions. Treatments, comprising untreated control, NaCl, KCl, CaCl2 and Na2CO3 each at 1.0 molar (M) solutions, were applied weekly for eight weeks. During both seasons, CaCl2 and Na2CO3 salinity had significant effects on soil pH and EC. During summer, salt types increased (106%–253%) dry shoot mass and reduced (53%–79%) root/shoot ratio. During winter, Na2CO3 salinity increased (114%) dry shoot mass, but the effects were not different to those induced by NaCl and CaCl2 salinity. All other plant growth variables were not affected by salt type. Salt type had significant effects on assimilation of selected nutrient elements in leaf tissues of M. zeyheri seedlings during winter. Sodium chloride did not have significant effects on nutrient elements, whereas KCl, CaCl2 and Na2CO3 significantly affected selected macronutrient elements and Zn. In conclusion, effects of chloride and carbonate salinity on M. zeyheri seedlings were both season- and salt type-specific, with seedlings displaying some degree of salt tolerance to chloride and carbonate salinity.

POPULATION FLUCTUATION OF CITRUS LEAFMINER, PHYLLOCNISTIS CITRELLA STAINTON (LEPIDOPTERA: GRACILLARIIDAE) IN THREE CITRUS VARIETIES

This work was carried out in a private farm of citrus orchard sited at Minia Elkamh district , Sharkia governorate, Egypt, during two successive years 2013/2014 and 2014/2015. Selected citrus trees represented three varieties ( noval orange , sweet orange and mandarin). The aim of this study was to monitor population fluctuation of citrus leaf-miner, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) on noval orange, sweet orange and mandarin , as well as to know the effect of air temperature , relative humidity and dew point on population fluctuation of larvae. The obtained results revealed that number of P. citrella larvae /leaf were more on noval orange than sweet orange and mandarin trees. Phyllocnistis citrella populations increased during summer months and declined during fall and winter. During the study period, 4-5 peaks of pest populations recorded on the summer shoots and 1 peak on the fall and winter shoots. Statistical analysis of the obtained data show that there are positive correlation between population of P. citrella and each of temperature, relative humidity and dew point.

Root growth and anchorage by transplanted 'Tifgreen' (Cynodon dactylon x C. transvaalensis) turfgrass.

Field experiments quantified factors affecting root growth and anchorage by transplanted 'Tifgreen' (Cynodon dactylon (L.) Pers.×Cynodon transvaalensis Burtt Davy) sod, a globally important warm-season C4 turfgrass. Vertical force required to detach recently transplanted sod from underlying soil was the measure of root anchoring strength. In early spring, date of sod harvest and transplantation was important to root growth and anchorage measured 30 days after transplantation. Delaying sod harvest/transplantation by about a month after the end of the winter shoot dormancy period increased root anchoring strength 200% and root dry mass 640% during the 30 days after sodding. The strong effect of early-spring sodding date on root anchorage was related to cumulative thermal time before sod harvesting. Root anchoring strength was directly proportional to the number, but not mass, of roots produced by transplanted sod. In late spring, anchoring of sod to very firm traffic-compacted clay was 87% greater than to loamy sand, measured 14 days after sodding. N-P-K fertilisation did not affect late-spring sod anchorage to loamy sand soil, measured 18 days after sodding, but did enhance shoot density and colour. Sod root penetration into a silt loam soil was unaffected by an initially dry surface layer when sufficient irrigation was used. Overall, root anchorage by transplanted Tifgreen sod was similar to, or greater than, values reported for cool-season C3 turfgrasses in similar circumstances.

The Influence of Willow Salix sp. Rose Insect Galls on Moose Alces alces Winter Browsing

Feeding trials were conducted with Moose (Alces alces) habituated to people to determine whether Moose prefer winter shoots of Scouler’s Willow (Salix scouleriana) with or without leafy willow rose insect galls created by rosette willow gall midges (Rabdophaga spp.). After sampling one or two shoots with galls, each Moose in the feeding trial showed a clear aversion to the galls and dropped or spit out parts of the willow shoot containing these structures in subsequent feeding bouts. Despite the reported importance of leafy materials in the fall and winter diets of Moose, these results suggest that morphological attributes of or chemical deterrents within galls may lead Moose to reject these structures in favour of gall-free shoots. Why galls are rejected is speculated upon, but remains untested.

Profiling of volatile compounds of Phyllostachys pubescens shoots in Taiwan

This study examined the influence of heating temperature and duration on volatile aromatic components of spring and winter Phyllostachys pubescens shoots using SPME. Results from GC-MS analyses revealed that the main constituents in both bamboo shoots at ambient temperature include methoxy-phenyl oxime, followed by n-hexanol and 3Z-hexenal, which gives a fresh green aroma. Comparing the different compounds, between spring and winter shoots, revealed that spring bamboo shoots at ambient temperature comprise 12.30% methyl salicylate, which provides protection against insect attack, and 9.71% epi-cedrol; while winter bamboo shoots comprise 17.00% 1-octen-3-ol, which produces a distinct mushroom aroma. After heating at 100 °C for 60 min, a marked increase in relative content of benzyl salicylate (43.30%) and a significant decrease in methyl salicylate content in spring bamboo shoots were observed; while the major compound in winter bamboo shoots was n-heneicosane (78.09%) and the content of specific 1-octen-3-ol significantly decreased.

Surveys of harvest technology of winter bamboo shoots

Winter bamboo shoots are widely used in Asian cuisine. We surveyed growth depth (tail depth and root depth), harvest speed, and harvest processes to provide information for developing new harvest technology. The tail depth of most winter bamboo shoots was 100–350 mm below the soil surface, and the root depth was 200–500 mm below the soil surface. Most winter bamboo shoots were difficult to locate with only the naked eye. The digging depth was 200–500 mm to cut winter bamboo shoots from the root. The highest harvest rate was 7.75 times faster than the slowest one and the average harvest speed ratio of men: women was about 1.71:1. The harvest process of winter bamboo shoots was divisible into three steps: searching, digging a hole (around the shoot) and cutting the root. The ratio of searching time to the sum of digging and cutting time was about 8:1, showing that searching required more time than digging and cutting together.

Paper birch (Betula papyrifera) shoot selection by moose (Alces alces) following a forest-cleaning experiment

In order to maximize food intake per harvesting effort and minimize energy expenditures required to move between feeding patches in nature, herbivores such as moose (Alces alces L.) generally select large plant shoots when browsing in winter. To determine moose preferences for shoots of different morphologies, an experiment was conducted in northern British Columbia in which shoots from birches cut at different times of the growing season were fed in 2 consecutive years to eight human-habituated moose in cafeteria-style feeding trials. The results indicate that moose preferred smaller winter shoots of birches regardless of when the parent plant was cut and also appeared to reject larger shoots containing sylleptic branches. It is argued that the preferences for smaller shoots by moose detected in these trials should be observable under natural conditions, but are generally only supported by literature from some parts of Scandinavia. The findings underscore the importance that factors such as mouth filling per harvesting effort, snow depth and consistency, predators and browse patch distribution must have on foraging decisions made by moose while browsing in the wild. Implications of the findings include the significance of cutting time on the size of shoots produced by birch after cutting, how this affects moose browsing birch and, subsequently, how managers can theoretically use cutting time as a tool in forest cleaning operations to direct the foraging efforts of moose towards or away from forest plantations.

FLORAL DEVELOPMENT OF ‘HASS’ AVOCADO UNDER SEMIWARM CLIMATE. PART I. INFLUENCE OF SHOOT AGE AND FRUIT LOAD

A multiyear research (1998 to 2006) was undertaken with the goal of developing field management tools to improve the productivity of ‘Hass’ avocado orchards in the semiwarm climate of Nayarit. The objectives were: a) to quantify the effect of ambient temperature on floral development of ‘Hass’, and b) to develop and validate prediction models to prognosticate critical stages of floral phenology. Floral development of ‘Hass’ was related to ambient temperature and mathematically modeled. Floral development on shoots of the winter flush was correlated to chilling days accumulated (CDA) at temperatures £ 21 °C, as well as the accumulated intervals between daily maximum and minimum temperatures (ACINT). In the case of summer flush shoots, they were associated to CDA with temperatures £ 19 °C, £ 20 °C and the ACINT. Two floral development prediction models ere obtained for winter shoots, winterCDA £ 21 (R2 = 0.99) and winterACINT (R2 = 0.96). In the case of summer flush shoots three prediction models were developed, summerCDA £ 19, summerCDA £ 20 and summerINTAC, all of them with R2 = 0.99.