Phenology and photosynthetic traits of short shoots and long shoots in Betula grossa

Leaf phenology, growth irradiance (i.e., photosynthetic photon flux (PPF) at the leaf surface) and photosynthetic capacity (A(area); measured at a PPF of 1000 micro mol m(-2) s(-1) and expressed on a leaf area basis) were investigated in early leaves (ELs) and late leaves (LLs) of Betula grossa Siebold & Zucc. trees. Early leaves first appeared on morphologically distinct long shoots and short shoots. The appearance of ELs, which was restricted to the bud break period, was followed by the successive appearance of LLs on long shoots only. Late leaves appeared successively until the middle of the growing season. Late leaves started to abscise around the middle of the growing season, whereas ELs on both long and short shoots did not abscise until near the end of the growing season. Solar irradiance was higher at the surface of LLs of late appearance than at the surface of either LLs of early appearance or ELs. Solar irradiance at the surface of ELs decreased after LLs appeared. In both long and short shoots, A(area) of ELs increased and then remained stable for 65-80 days before starting to decrease. Although A(area) was higher in LLs than in ELs for a short time in August, it started to decrease earlier in LLs than in ELs. Area-based nitrogen concentration (N(area)) was higher in LLs than in ELs after August. Although N(area) decreased slowly in ELs after August, it did not decrease in LLs. In both ELs and LLs, A(area)/N(area) decreased with time. The crown was thus characterized by a rapidly growing surface with young LLs having high A(area) and by shaded inner parts with ELs having stable low A(area).     

Yield—Density diagram for natural deciduous broadleaved forest stands

A yield—density diagram for natural deciduous broad-leaved forests in Hokkaido was devised. It consists of Y—N curves, equivalent diameter curves, equivalent mean diameter curves, a B-point curve and a full density curve. The Y—N curve is derived from the relation between cumulative summation (Y) of individual tree volume from the maximum sized tree to one of a certain given volume, and number (N) of these trees, and is expressed by the reciprocal equation of two parameters, A and B. The equivalent diameter curve expresses the number of trees whose diameters are larger than a certain size. The equivalent mean diameter curves express the number and volume of trees of selected mean diameters. The B-point curve is a hypothetical trajectory of the B-point of the C—D curved ruler (C—D rule) which is fitted to each Y—N relation, throughout the course of stand development. The full density curve indicates the upper limit of the number and volume of the standing trees. Utilizing this diagram, we can comprehend numbers, volumes and tree diameters in a stand and among stands.A method is devised of predicting the number and volume of each diameter class of a stand several years after thinning. Thinned trees are assumed to be selected equally from each diameter class so that the Y—N curves are fitted equally to the Y and N data before and after thinning. Volume growth of individual trees is assumed to be proportional to their volumes after thinning. The current volume growth of the stand after crown closure is assumed to be constant irrespective of the stand age. Tree mortality after thinning is assumed to be negligible. With these assumptions, a trajectory of the Y—N curve through thinning is determined, and a yield after n years from thinning is predicted. Comparing the Y—N curve of a thinned stand with that of an unthinned stand after n years from thinning, we can comprehend the thinning effect.     

Risk evaluation and tree improvement as components of intensive forest management in Japan

Forestry practice differs from agricultural crops practice owing to the huge size of trees, their longevity and the variety of uncontrollable conditions under which they grow. Even with intensive forest management, the actual effects of investment of labour and materials in the forest seem to be fairly small because of the size of the forest and the long harvest rotation. Since we expect to produce both a higher quantity and a higher quality of timber with intensive forestry, it is very important to have adequate counter-measures to the fatal or destructive factors which affect forest establishment and growth. In Japan, in the field of forest tree breeding, we are making maps as information sources for decision making, in which iso-lines show the degrees of damage due to fatal factors such as pests and diseases. If there is more than one fatal factor overlapping in an area, it might be difficult to grow forests for commercial purposes. We have to decide how to use the forest land in these areas, or how to take counter-measures such as tending, chemical control, genetic improvement or even a change in the tree species. As forestry has a long harvest rotation, it is necessary to have ‘a quality control system’ in management, in which a follow-up assessment of planting materials, tending techniques in combination with site conditions, and fatal factors will be made. In this situation, forest tree improvement (breeding) seems to be of prime importance in intensive forest management in the future.     

Quantifying growth in maricultured corals using photogrammetry

In coral mariculture, growth is one of the most common ways to track success. However, numerous methods of monitoring coral growth make comparative studies challenging. A literature review of 39 studies from 1982 to 2017 indicated that the most predominant non‐invasive methods used were linear and areal measurement and these were evaluated for their accuracy using nursery‐reared corals. The monthly change in linear and areal growth rates of six coral species (n = 215), Pocillopora acuta, Hydnophora rigida, Merulina ampliata, Podabacia crustacea, Echinopora lamellosa and Platygyra sinensis were measured via photogrammetry. We tested whether the planar area of coral colonies can be estimated using three geometric formulas of linear measurements. Based on the literature review, the six types of measurement methods were namely linear, volume, weight, area, count of polyps/branches and calcification, in decreasing order of application. Our results showed that the change in area calculated by geometric mean diameter (GMD) formulas provided the most accurate estimation among the three formulas and was strongly correlated with planar area (R² ≥ .60; p < .05) for all coral species, except E. lamellosa and Pl. sinensis. However, our findings suggest that it is not ideal to use geometric formulas to estimate the change in area. Instead, we posit that areal photogrammetry represents the simplest yet accurate non‐invasive method for rapid monitoring of extensive areas of corals in situ. Lastly, we discuss the recommendations and limitations for areal photogrammetry.     

Micropropagation of Bolaina blanca (Guazuma crinita Mart.), a fast-growing tree in the Amazon region

Rapid clonal propagation of Bolaina blanca (Guazuma crinita Mart.) was established by the subculturing of the shoot-tips from aseptically germinated seedlings on woody plant medium (WPM) supplemented with trans-zeatin [trans-6-(4-Hydroxy-3-methylbut-2-enylamino)purine] (ZEA). After 45 days of culture, a seven-fold multiplication rate was achieved on WPM containing 10 μM of ZEA. Obtained shoots were simultaneously elongated and rooted on WPM containing 1 μM of kinetin [6-furfurylaminopurine] (KIN). After 60 days of culturing the growth of shoots was evident, and high rooting percentages were obtained. The plantlets were transferred into pots with vermiculite and acclimatized successfully in plastic boxes with transparent cover inside the growth cabinet.     

Influence of foliar phenology and shoot inclination on annual photosynthetic gain in individual beech saplings: A functional–structural modeling approach

We developed a functional–structural plant model for Fagus crenata saplings and calculated annual photosynthetic gains to determine the influences of foliar phenology and shoot inclination on the carbon economy of saplings. The model regenerated the three-dimensional shoot structure and spatial and temporal display of leaves; we calculated the hourly light interception of each leaf with a detailed light model that allowed us to estimate hourly leaf photosynthetic gain taking leaf age into account. To evaluate the importance of simultaneous foliar phenology and slanting shoots in beech saplings, we calculated the photosynthetic budgets for saplings with contrasting foliar phenologies and shoot inclinations. In our simulations, we distinguished between simultaneous and successive foliar phenologies, upright and slanting shoot inclinations, and environments with and without a vertical gradient in light intensity. Other model parameters (including photosynthesis vs. light curve, leaf size, and leaf shape) were obtained directly from live beech saplings. With no vertical gradient in light intensity, modeled saplings with simultaneous foliar phenology and slanting shoots (as in live beech) had larger annual photosynthetic gains than saplings with other combinations of traits. Hence, simultaneous foliar phenology and slanting shoots are efficient ways to display leaves in the shaded forest understory light regime where beech saplings thrive. In the presence of vertical light gradients, which can occur in canopy gaps, saplings with upright shoots had larger annual photosynthetic gains than counterparts with slanting shoots. Although mean daily photosynthetic gains of saplings with successive foliar phenology were elevated by exposing leaves to strong light when young and productive, the annual photosynthetic budget of these saplings was reduced (compared to saplings with simultaneous foliar phenology) by their relatively short leaf lifespan. Overall, our results suggest that slanting shoots with simultaneous foliar phenology are particularly successful in shaded environments, where beech often dominates, because they appear to maximize the annual carbon budget by avoiding self-shading and extending leaf lifespans.     

日本落叶松同工酶变异的基因分析及无性系鉴别

同工酸可作为遗传图谱构建和无性系鉴别的重要遗传标记．以92个日本落叶松无性系种子为实验材料，采用垂直平板聚丙烯酰胺凝胶电泳法，取其胚乳进行了同工酶分析，结果表明：11种酶系统至少由24个基因座所控制，多数座位存在2个或2个以上的等位基因；多数座位等位基因的基因频率差异很大；各无性系之间至少在一个以上的基因座上存在差异．并确定了92个无性系的同工酶基因型．     

Evaluation of leaf display of evergreen broadleaved tree species and deciduous tree species in warm temperate conifer plantations

We investigated the sapling leaf display in the shade among trees of various leaf lifespans co-occurring under the canopy of a warm-temperate conifer plantation. We measured leaf-area ratio (aLAR) and morphological traits of saplings of evergreen broadleaved tree species and a deciduous tree species. Although we found large interspecific and intraspecific differences in aLAR even among saplings of similar size in the homogeneous light environment, we did not find a consistent trend in aLAR with leaf lifespan among the species. While deciduous trees annually produced a large leaf area, some evergreen broadleaved trees retained their leaves across years and had aLAR values as high as those of deciduous trees. Among leaf-level, shoot-level, and individual-level morphological traits, aLAR was positively correlated with current-year shoots mass per aboveground biomass in deciduous trees, and with the area of old leaves per aboveground mass in evergreen broadleaved trees. Thus, tree-to-tree variation in the degrees of annual shoot production and the accumulation of old leaves were responsible for the interspecific and intraspecific variations in aLAR.     

Volatile components of Japanese cedar cultivars as repellents related to resistance to Cryptomeria bark borer

The response of the essential oils and their components toCryptomeria bark borer has been studied. The oils of inner bark and sapwood of resistant cultivars acted as a repellent toCryptomeria bark borer rather than as an attractant, whereas those of susceptible cultivars acted as an attractant.-Terpineol, nerolidol,-cadinene,-eudesmol, terpinolene, and cedrol showed high repellent activity. The relative contents of the former four compounds were larger in resistant cultivars than in sensitive cultivars. It suggests that these four compounds might be one of the causes of resistance toCryptomeria bark borer. The contents of terpinolene and cedrol were small, and these two compounds may have no or a small influence on resistance. Although some of compounds acted as attractants forCryptomeria bark borer, it was not attributable to the difference in the bark borer response of Japanese cedar because of the relatively low ratio of these compounds in each essential oil and the small differences in the ratios between resistant and susceptible cultivars.     

Effects of flooding on leaf dynamics and other seedling responses in flood-tolerant Alnus japonica and flood-intolerant Betula platyphylla var. japonica

Two-year-old seedlings of Alnus japonica Steud. and Betula platyphylla var. japonica Hara were flooded from mid-June to early November, to study the effects of flooding on seedling survival and growth, morphological changes in stems and roots, leaf emergence, leaf fall, and leaf longevity. In A. japonica, growth was not affected by flooding, except for a slight decrease in height growth, but some morphological changes of stems and roots were observed, i.e., stem base hypertrophy, hypertrophied lenticels, formation of adventitious roots and development of new roots. In B. platyphylla var. japonica, growth was severely reduced by flooding and all seedlings died by the 20th week of flooding, without showing any adaptive morphological changes in stems or roots. Flooding induced rapid depression of leaf emergence, promoted leaf abscission, and reduced leaf longevity in B. platyphylla var. japonica. In contrast, in A. japonica, basal leaf senescence was delayed in flooded seedlings, thereby extending leaf longevity compared with unflooded seedlings.