Wood Maturity Research Articles

Axial and radial wood maturation in three mistletoe ‘giants’ (Loranthaceae)

Summary The formation of juvenile wood featuring greater cell variation relative to mature wood is a well-known phenomenon. Once wood attains maturity, it has both more consistent cell sizes and organization. This is especially well understood for large trees used for paper and timber production, but less so for shrubs and bushes. Despite its importance, there is very little information on the wood anatomy and wood maturation available for some lineages such as the Loranthaceae (Santalales), which are mostly composed of shrubby mistletoes. Here, we studied three of the largest known mistletoe species to analyse the variation of xylem structure within both the radial and the axial axis of the stem. Using classical anatomical techniques, we determined at which point, both in thickness and in distance from the apex, these parasitic plants start producing mature wood. We measured vessel element length, fibre length, vessel diameter, and vessel density on multiple points of either very thick or very long branches of three different mistletoe species: Struthanthus rhynchophyllus, Tripodanthus acutifolius and Psittacanthus robustus. Our findings suggest that Loranthaceae mistletoes reach wood maturity rather early, with very minor differences between juvenile and mature woods. These results open new avenues for further research on the wood anatomy of mistletoe’s stems, enabling the use of smaller samples, such as those commonly present in herbarium vouchers.

Anatomical properties of Hibiscus macrophyllus and its mature wood development

Abstract The Hibiscus macrophyllus tree is widely planted in Indonesia especially on Java Island. It has several advantages to be developed commercially as a community or plantation forest compared to the famous introduced species Falcataria moluccana and Anthocephalus spp., including faster growth, higher wood density, and better stem morphology (straighter, more rounded, and lesser branches). However, information about the basic properties of this wood grown in plantations is limited. This study aimed to investigate the anatomical properties of H. macrophyllus and their variation at three ages (8, 12 and 16 years old), as well as to predict the mature wood development by using radial variation in fiber length, microfibril angle (MFA), and wood density from pith toward the bark as the indicators. The wood samples were obtained from a community forest area at Ciamis Regency, West Java Province. Furthermore, anatomical characteristics were examined through wood slides following the IAWA List, while fibre and vessel element dimensions were measured through macerated specimens prepared by modified Franklin’s method. The MFA was determined by X-Ray Diffraction, while wood density was measured in line with British Standard 373-57. The results showed that the anatomical structures were not influenced by tree age, except for wood porosity, and fibre and vessel element dimensions. The 16-year-old tree tended to be semi-ring-porous, the younger trees were diffuse-porous, while the fiber and vessel element length, as well as the diameter, were decreased. Meanwhile, the wall thickness was increased. The fibre length, MFA, and wood density were useful indicators for wood maturity that seemed to be developed at about 11 years of age.

The Rate of Water Loss in Relation to Internodes Position and Wood Maturity in Vine Chords

The purpose of study was to assess the rate of water loss from the strings of vines in relation to internodes position on vine chords and degree of wood maturity. The biological material was represented by Burgund vine cultivar, to which were analyzed individually all internodes distributed on the chord length (internodes number IN2-19). The rate of water loss and associated parameters (maximum rate of water loss - RWLMax, total drying time - T, time to achieve RWLMax - tRWLMax) were determined from the Burgund vine cultivar, in controlled condition. Parameters studied were associated with dry matter content (refractometric method), degree of maturity of the wood, and internodes positions on chord. RWL Max had higher values in the basal internodes (IN2; RWL Max = 0.252±0.005 g/min) and lower in the apical internodes (IN17-19; RWLMax = 0.202±0.011 g/min). RWLMax distributions values, according to the position of internodes on chord was described by a third degree polynomial function, statistical safety (R2 = 0.949, p<0.01). Dry substance content in internodes (sugar) was correlated with the total time of water loss (T; R2 = 0.945), the time to reach the maximum rate of water loss (tRWLMax; R2 = 0.855), and maximum rate of water loss (RWLMax; R2 = 0.984).

Clonal selection of rootstocks by means of determination of hard bast layers

Determination of the number of closed circles of hard bast plates on matured shoot cuttings, which is used for wood maturity control, was applied as selection method to four rootstocks: Vitis berlandieri x V. riparia Kober 5 BB, Teleki 5 C, Craciunel 2 and V. riparia x V. rupestris Schwarzmann. For each selected vine stock the linear regression of wood maturity was calculated, considering the distance from the base of the cane. From the linear regression equation the average length of the matured wood part was calculated for each stock The results of 3-year investigations show that the degree of rootstock wood maturity is not only dependent on the meteorological conditions of the years but is also genetically conditioned.

Anatomical Changes During Transition from Juvenile to Adult Wood in Branch and Main Trunk Xylem of Subabul (Leucaena leucocephala [Lam.] de Wit)

The anatomical changes occurring during transition from juvenile to mature wood were studied in the branch and main trunk of Leucaena leucocephala. To confirm the wood maturity in the 5-yr-old tree, the anatomical features were compared with the adult wood collected from the main trunk of a 15-yr-old tree. In both the branch and wood of the trunk, most of the anatomical features—such as increase in dimensions of fibers and vessel elements, and decrease in frequency of vessel elements and rays—were gradual during radial growth from pith to periphery. A noticeable anatomical change is observed in the transition of triseriate rays to multiseriate rays in the region of wood which is about 5.5 cm away from the pith. The ray dimensions and anatomical features of other elements from the periphery of the branch and 5-yr-old trunk xylem match with that of 15-yr-old main trunk wood. This indicates that in both the branches and main trunk of Leucaena, transition from juvenile to adult or mature wood occurs after the trees have attained 14 cm radial growth.

Vertebrates respond differently to human disturbance: implications for the use of a focal species approach

Focal species are surrogates assuming that all species under consideration respond similarly to the threatening processes. Focusing management only on a small number of species would improve conditions for other species. However, the across-taxa congruency of the response to threatening processes, and the subsequent efficiency of focal species as surrogates, has seldom been tested. In this study, we evaluated the effects of recreational disturbance and wood structure on the communities of terrestrial vertebrates in the wood patches of a large urban park. We measured two effects of recreation: direct disturbance (people presence) and litter disturbance (effect of trampling). We used multiple techniques to assess the distribution of small mammals, birds, reptiles and amphibians in 44 wood patches. Disturbance and wood maturity influenced the distribution of some species and the species richness of amphibians and reptiles; however, the pattern was not consistent across species within classes or among classes. The performance of focal species as a multi species umbrella was poor. Our results suggest that species specific differences in the response to the same source of disturbance can be strong; these differences can hinder the usefulness of focal species as surrogates and as a management tool.

PHOTOSYNTHETIC INHIBITION OF 'SEYVAL BLANC' GRAPEVINES WITH TERBACIL

PHOTOSYNTHETIC INHIBITION OF 'SEYVAL BLANC' GRAPEVINES WITH TERBACIL

Effects of Powdery Mildew on Vine Growth, Yield, and Quality of Concord Grapes.

Vitis labruscana 'Concord' is a widely planted grape cultivar grown in the United States for processing into juice and other products. Concord fruit are sporadically but sometimes severely damaged by the grape powdery mildew pathogen, Uncinula necator. The effects of powdery mildew on vine growth, yield, and quality of Concord grapes at three levels of cropping intensity commonly found in commercial grape production were determined in vineyard studies. Top-wire cordon-trained Concord vines were balance pruned, pruned to retain 80 nodes, or minimally pruned. Replicated plots of the foregoing were then either protected from powdery mildew by regular fungicide applications, or were inoculated and left unsprayed. Over a 4-year period, the effects of foliar infection on vine growth, yield, and juice quality of unsprayed vines were compared with vines that received a conventional protection program of four fungicide applications. Failure to control powdery mildew resulted in a chronic reduction in wood maturity measured as the number of nodes on canes that developed periderm. The reduction in nodes did not reduce yield, possibly due to compensation in shoots produced from the remaining nodes. Powdery mildew did not affect bud survival or vigor, measured as the number of shoots produced per node on retained canes. The most significant effects of powdery mildew were on berry sugar levels and juice color and acidity, which on the unsprayed vines were sometimes reduced below minimally acceptable thresholds for processed grapes. Significant reductions due to powdery mildew in these parameters occurred in all three pruning treatments, but were most pronounced at higher cropping levels.

First Report of Three Phaeoacremonium spp. Causing Young Grapevine Decline in California.

A grapevine decline of unknown etiology is currently under investigation in California. Two- to 5-year-old vines show low vigor with undersized trunks, short internodes, uneven wood maturity, sparse foliage, and stunted, chlorotic leaves with interveinal chlorosis and necrosis. Trunks viewed in cross section show dark streaking in few to most of the vascular elements. Pith is compacted and discolored; the surrounding wood is dry with a silvery sheen. Primary roots also show dark streaking in the vascular elements and total root biomass is reduced. Phaeoacremonium spp. were consistently isolated from the roots, crowns, and lower portions of the rootstocks of declining vines but not from adjacent healthy vines. Phaeoacremonium spp. grew slowly out of infected tissues, but sporulated abundantly in culture. Identification was verified from a published key (1). Phaeoacremonium chlamydosporum and P. inflatipes were isolated throughout the northern and central California production areas, but P. aleophilum was isolated only in Riverside County. Koch's postulates were completed for Phaeoacremonium spp. by dipping roots of 2-month-old Carignane grape seedlings (n = 80) in a 108 spores per ml suspension for 30 min. Plants were potted in an artificial soil mix and held in a growth chamber at 25°C. Over 50% of plants inoculated with Phaeo-acremonium spp. developed root, stem, and vascular symptoms within 8 weeks. Each of the individual pathogen species was reisolated from over 75% of the inoculated plants but never from the controls. Similarly, all three Phaeoacremonium spp. are associated with wilt and decline diseases in grapevines in Africa (1) and Europe (2) but this is the first report in North America. While several names for this disease have been used previously with older grapevines, including Esca, apoplexy, and black measles (3), we propose using Phaeoacremonium grapevine decline to describe the diseases caused by P. aleophilum, P. chlamydosporum, and P. inflatipes on young vines.

First Report of Black-Foot Disease, Caused by Cylindrocarpon obtusisporum, of Grapevine in California.

Black-foot disease, caused by Cylindrocarpon obtusisporum (Cook & Harkn.) Wollenweb., impacts young table and wine grape (Vitis vinifera) plantings throughout California. Two- to 5-year-old grapevines showed reduced vigor with small-sized trunks, shortened internodes, uneven wood maturity, sparse foliage, and small leaves with interveinal chlorosis and necrosis. In cross-section, trunks showed dark brown to black streaking in a few to most of the vascular elements. Symptoms included a reduction in root biomass and root hairs with sunken, necrotic root lesions. Pith of affected vines was compacted and discolored. Isolations made from roots, vascular elements, and pith tissue consistently yielded colonies of C. obtusisporum as verified by descriptions in standard texts. Koch's postulates were completed by dipping the roots of cv. Carignane seedlings in a 108 spore per ml suspension for 30 min. Plants were repotted in an artificial soil mix and held in a controlled environment facility at 24°C. Typical black-foot symptoms developed on 92% of the plants within 8 weeks. Control plants dipped in distilled water remained healthy. Cylindrocarpon destructans, a species closely related to C. obtusisporum, was first reported to cause "black-foot disease" on young vines in 1961 (2). In 1975, C. obtusisporum was reported to produce similar "black-foot" symptoms (1). We propose the common name Cylindrocarpon black-foot disease be used with both species.

Shoot Topping and Ethephon Effects on White Riesling Grapes and Grapevines

Canopy modification by shoot topping or ethephon application was examined with <i>pendelbogen</i>-trained White Riesling grapevines in the hot, humid Piedmont region of Virginia. Treatments were: control, two levels of shoot topping (10 <i>vs.</i> 20 leaves per shoot retained) or ethephon application to shoot tips (600 mg/L). Topping shoots to maintain 10 or 20 leaves per shoot reduced annual cane pruning weights by an average of 61% or 24%, respectively, compared with non-topped vines. The application of ethephon produced a vine size comparable to that of vines hedged to 20 leaves per shoot. Canopy insolation was least with control vines (due to shoot tops shading original canopy) and similar among other treatments. Vines topped to 20 leaves per shoot produced more fruit than did vines topped to 10 leaves per shoot. More fruit was harvested from shoot-topped vines than from control vines in two of three years. Neither wood maturity nor dormant bud survival were adversely affected by shoot topping or ethephon application. Greatest fruit soluble solids at harvest were generally observed with vines topped to 20 leaves per shoot. Shoot topping resulted in fruit with lower titratable acidity at harvest than with control vines, but fruit pH was not appreciably affected by any treatment. Fruit rot incidence and the concentrations of rot-associated metabolites (glycerol, ethanol, and acetic acid) were significantly and mutually correlated. Fruit rot and rot metabolites were greatest with control and ethephon-treated vines and were least with vines whose shoots were topped to 10 leaves. Shoot topping to 15 to 20 leaves per shoot appears appropriate with vigorous, low-trained White Riesling to maximize benefits of this remedial canopy management practice in the humid mid-Atlantic United States.

Mechanical Winter Injury in Grapevine Trunks

Trunk samples of Gewürztraminer, Chardonnay, Concord, and Riparia were collected during the 1978 winter season from vineyards of the Niagara Peninsula in Ontario and analyzed for surface resistance to water uptake, moisture transfer and content in the xylem and phloem and for mechanical freezing damage in phloem and phellem. Staining methods were used to evaluate surface resistance and moisture migration. Freezing experiments were performed in an electronically controlled freezing chamber capable of simulating winter conditions in Ontario vineyards. The experiments showed that the late maturing Gewürztraminer cannot maintain its content of freezable water below critical levels during thawing periods due to inferior wood maturity with little suberin protection. Excessive ice formation in subsequent freezing periods will cause mechanical ruptures in cell and vessel walls of the phloem as well as in the phellem epidermis. Mechanical freezing injury is proportional to the concentration of freezable water and the temperature drop below the supercooling point of the tissue fluid.

日長および温度がブドウの生育ならびに花房分化に及ぼす影響

The combination effects of day-length and temperature on the growth and bunch differentiation of grapes were observed with one-year-old grafted vines of Delaware (V. labruscana) and Muscat of Alexandria (V. vinifera) in natural light growth cabinets by treating as follows; i) 20°C-short day (8-hour), ii) 20°C-long day (16-hour), iii) 30°C-short day (8-hour), and iv) 30°C-long day (16-hour).1) In Delaware, shoot growth and bunch differentiation were greatly retarded on short days regardless of temperature, while promoted remarkably on long days, the trend being more marked at 20°C than at 20°C. However, shoots elongated so rapidly on 30°C-long days that most of lateral buds at their basal part became barren.2) In Muscat of Alexandria, shoot growth and bunch differentiation were less sensitive to day-length than to temperature. Shoot growth was considerably ensured at 30°C even on short days, though it was greatly retarded on 20°C-short days. Bunch differentiation was best on 30°C-long days, followed by 30°C-short days, 20°C -short days, and 20°C-long days in the order. Particularly no bunch differentiation occurred on 20°C-long days all along the shoot.3) Therefore, to utilize fully the room space in the vine growing under glass or plastic film, 20°C-long days seem to be best condition for Delaware, and 30°C-long days for Muscat of Alexandria from the stand-points of shoot growth and bunch differentiation. It is, however, noticeable that root growth and wood maturity were generally better on short days than on long days in both cultivars.

The Spectra of Reaction Wood Lignins in Relation to Wood Maturity

The Spectra of Reaction Wood Lignins in Relation to Wood Maturity