Inheritance of the trait of male sterility inCryptomeria japonica

Matings of male-sterileC. japonica and fertile eliteC. japonica, as well as backcross seedlings of male-sterile trees, were carried out to clarify the genetic trait of male sterility of theC. japonica. The seeds from male-sterileC. japonica were germinated in an incubator and grown them in the greenhouse between 1994 and 1997. The seedlings were treated with 100 ppm gibberellin at early July 1994 and early July 1995 to promote the formation of male flowers. In the middle of January 1995, the male flowers of all seedlings were examined under the microscope to confirm the production of pollen. In January 1996, pollen did not developed in to the male flowers from the seedlings between the fertiled elite and backcrossC. japonica. In January 1997, all seedlings of eliteC. japonica produced pollen in their male flowers; however, pollen did not developed in 55 out of 120 backcrossed seedlings. This evidence suggests that the heredity pattern of male sterility inC. japonica is nuclear male sterility controlled by a pair of recessive genes.     

The effect of alternating temperature on the rest break process of male flowers of Cryptomeria japonica D. Don

In order to develop a model for predicting the period of male flower anthesis in Cryptomeria japonica, it is requisite to clarify the rest break process in male flowers. In this study, the effect of alternating temperatures in a daily cycle on rest break was investigated using twigs bearing male flowers from three clones of C. japonica. Four temperature treatments with the same daily mean of 8°C were applied to sample twigs over a period of 35 days: (1) 8°C constant (TR-A); (2) 7°–10°C alternating (TR-B); (3) 5.5°–13°C alternating (TR-C); and (4) 4°–16°C alternating (TR-D). After treatment, the sample twigs were forced to bloom at a constant temperature of 16°C, and the cumulative effective temperatures (CETs) required for anthesis were compared. While the CETs for anthesis were the same for TR-A and TR-B, that for TR-C was significantly higher. After TR-D, almost no male flower bloomed, indicating that this treatment was ineffective in breaking rest. When considering these results on an hour basis, it was a reasonable interpretation that 13°C had no effect on breaking rest while the temperatures below 10°C were all equally effective. On the other hand, temperatures of 16°C or above were considered to have an antagonizing effect that cancels the effects of chilling temperatures below 10°C. These results suggest that the effects of high temperatures during the daytime in chilling periods should be properly incorporated into a model of the process by which rest of male flowers is broken.     

Resource level as a proximate factor influencing fluctuations in male flower production in Cryptomeria japonica D. Don

Airborne pollen of Cryptomeria japonica causes severe pollinosis, and the number of people suffering from pollinosis has increased rapidly during recent decades. Male flower production in C. japonica shows annual variability; thus, predicting male flower production for the following spring could be a countermeasure against pollinosis. We analyzed factors that explain fluctuations in male flower production of C. japonica according to parameters reflecting internal resource dynamics based on field observations. In addition, we carried out experiments to regulate available resource levels using artificial shading to test the effect of internal resource levels on the number of male flowers produced. We found that temperature and precipitation in the previous summer and a relative increase in male flower production in the previous year were negatively related, whereas sunshine duration in the previous summer and diameter at breast height were positively related to the current year increase in male flower production. The number of male flowers was significantly reduced by the shading treatment and was positively correlated with the amount of total non-structural carbohydrates in the root. These results suggest that understanding the parameters controlling internal resource levels could lead to more accurate predictions of male flower production.     

Study of sugi (Cryptomeria japonica D. Don) with male-sterility gene using CAPS markers

The frequency of open-pollinated male-sterile seedlings from a male-sterile mother tree in Cryptomeria japonica D. Don was determined in 765 open-pollinated seedlings. Pollen was not formed by 29 out of the 765 seedlings. To find pollen donor candidates for 29 male-sterile seedlings, a male-sterile tree was crossed with five individuals in the neighborhood of the mother tree. Analysis of microspores in male flowers of F₁ seedlings revealed that one of the five individuals had a heterozygous male-sterility gene. Paternity tests were conducted on the 29 male-sterile seedlings using eight kinds of CAPS markers in C. japonica. The pollen parents of 29 male-sterile seedlings were not only a tree in the neighborhood of the mother tree, but also other trees. Since it was found that the pollen parents of four of the male-sterile seedlings were not in the study plot, it was inferred that C. japonica trees that possess the male-sterility gene grow in other places and may be widely distributed.     

The effect of low temperature adversity on male flowers and pollen inLarix olgensis

The electric conductivity of pollen life-force and male flowers ofLarix olgemis on condition of low temperature adversity has been respectively measured by means of fluorescent dying method and conductivity method in 1992 and 1994. The results indicate that: (1) If the same clonal pollen is treated at equal time at different low temperatures, there are significant differences in pollen life-force, the pollen life-force is the largest between O°C and -3°C, in higher or lower temperature range, the pollen life-force will decrease. The measurement of electric conductivity of male flowers proves that the low temperature of below -3°C is the main reason that the cell membrane is damaged and the pollen life-force decreases. (2) The same clonal pollen life-force at the same low temperature will gradually decrease with the increasing of frozen time. Its main reason is that suffocation and losing body fluid result in the damage of cell membrane, the measurement of electric conductivity of male flowers can prove that. (3) If pollen is treated with the same low temperature, the humidity will be the main factor of affecting pollen life-force. (4) There are significant differences inLarix olgensis’s resistance against low temperature in its different growth stage, the male flower’s resistance of near pollen spreading period is low. (5) The resistance is different within clones. (6) The resistance against low temperature ofLarix can be increased by means of chemical treatment.     

Cytological study of a male-sterile Cryptomeria japonica that does not release microspores from tetrads

To determine the mechanism of male-sterility Cryptomeria japonica tree Shindai3, the process of microspore development was observed under light and fluorescence microscopy. Microspore development in the Shindai3 was normal until the tetrad stage, but separation of the microspores from the tetrads was not observed even after callose had been degraded. In contrast to the microspore stage in a male-fertile tree, amorphous substances were observed around tetrads in the Shindai3, and the amount of the amorphous substance increased from the middle of November to the middle of December. The substances are hypothesized to prevent the separation of individual microspores from tetrads by inducing adhesion between microspore cells within the tetrad or enclosing the tetrads. The form of the tetrads in the Shindai3 was maintained until just before the pollen dispersal season, but they ultimately degenerated. The results of this study indicate that the mechanism causing male sterility in Shindai3 differs from that previously reported for other male-sterile trees of C. japonica.     

余甘子开花物候特性研究

余甘子所有的品种都是先开雄花后开雌花；一般雌花可授期比雄花散粉期来得晚，且持续时间短．可授期含在散粉期内。余甘子不同品种雄花开花物候期有很大差别，品种间相差最长28d。雌花开花持续时间比雄花要短得多，不同品种在16～21d之间变动；雌花盛花期更短，不同品种在8～12d间。余甘子多个品种存在多次开花结实现象；雄花的第一次持续时间和盛花持续时间都长，在第二、三次则大大缩短。第一次的果实产量是全年产量的主要保证。兰丰和粉甘品种开花同步指数最高．能相互较好地授粉．适合在建园中进行品种配置。     

Factors shaping genetic structure within populations ofEurya japonica (Theaceae)

Starch-gel electrophoresis was used to resolve nine polymorphic enzyme loci from leaf tissue collected from 20 Korean populations ofEurya japonica in order to determine differences in allele frequencies between male and female trees. In addition, 84 adults were sampled and mapped in a population located on Naenaro Island in Korea to examine spatial genetic structure using spatial autocorrelation analysis. Allele frequencies between males and females gave few contribution to the genetic structuring within populations. Only nine (5%) of 180 cases were significantly different from both sexes in allele frequencies. On the other hand, Moran'sI was significantly different from the expected value in 31 (23.5%) of 132 cases. In the shortest distance (0<5m),I was significantly positive in 10 (22.7%) of 44 cases. The results indicate that a significant small scale genetic structure was detected in the population and patch widths were inferred to be approximately 5–7 m. A nonrandom distribution of genotypes may be indicative of restricted gene flowvia seed and pollen dispersal, and patchy establishments of genetically distinct individuals. These factors are responsible for shaping population genetic structure ofE. japonica.     

Using degree-day accumulations and host phenology for predicting larval emergence patterns of the olive psyllid, <Emphasis Type="Italic">Euphyllura phillyreae</Emphasis>

The olive psyllid, Euphyllura phillyreae Foerster is one of the most destructive pests on buds and flowers of olive tree (Olea europaea L.) in May when the olive growers cannot apply any insecticides against the pest. Temperature-dependent development of the psyllid was studied at constant temperatures ranged 16–26°C. A degree-day (DD) model was developed to predict the larval emergence using the weekly cumulative larval counts and daily mean temperatures. Linear regression analysis estimated a lower developmental threshold of 4.1 and 4.3°C and a thermal constant of 164.17 and 466.13 DD for development of egg and larva, respectively. The cumulative larval counts of E. phillyreae approximated by probit transformation were plotted against time, expressed as the sum of DD above 4.3°C, the starting date when the olive tree phenology was the period of flower cluster initiation. A linear model was used to describe the relationship of DDs and probit values of larval emergence patterns of E. phillyreae and predicted that 10, 50 and 95% emergence of the larvae required 235.81, 360.22 and 519.93 DD, respectively, with errors of 1–3 days compared to observed values. Based on biofix depends the development of olive tree phenology; the DD model can be used as a forecasting method for proper timing of insecticide applications against E. phillyreae larvae in olive groves.     

Effects of transgenic cry1Ab rice pollen on fitness of Propylea japonica (Thunberg)

The transgenic rice lines Kemingdao 1 (KMD1) and Kemingdao 2 (KMD2) contain a synthetic cry1Ab gene derived from Bacillus thuringiensis Berliner and are highly resistant to rice stem borers and foliage-feeding lepidopterans. Propylea japonica (Coleoptera: Coccinellidae) is an important predator of rice insect pests; it also uses rice pollen as a food source under natural conditions. In the present study, the effects of KMD1 and KMD2 pollen expressing Cry1Ab protein on the fitness of P. japonica were assessed in the laboratory. P. japonica larvae and adults were provided with the following four diets: KMD1 pollen with the aphid Myzus persicae, KMD2 pollen with M. persicae, nontransgenic Xiushui 11 (parent variety of KMD1 and KMD2) pollen with M. persicae, and M. persicae only (KMD1–pollen, KMD2–pollen, XS11–pollen, and aphid treatments, respectively). The results showed that the longevity of female adults in the KMD1–pollen treatment was significantly lower than that in the XS11–pollen treatment, but was not significantly different from that in the KMD2–pollen and aphid treatments. Newly emerged males in the KMD2–pollen treatment were evidently less vital than those in the XS11–pollen treatment, but not significantly different from those in the KMD1–pollen and aphid treatments. The development, survival and reproduction indices for the three pollen treatments did not differ significantly from one another. In short, Bt toxin expressed in Bt rice pollen had no evident negative impacts on P. japonica fitness when the pollen was used as a food by this beetle.This revised version was published in March 2005 with corrections to the names of the authors.     

Differentiation of seed germination traits in relation to the natural habitats of three <Emphasis Type="Italic">Ulmus</Emphasis> species in Japan

Germination traits of three Japanese Ulmus species, including two summer-fruiting species, U. davidiana var. japonica (UD) and U. laciniata (UL), and an autumn-fruiting species, U. parvifolia (UP), were investigated. Germination tests that controlled light (16 h dark–8 h light/24 h dark) and temperature (alternating 20–30°C/constant 23°C) conditions were conducted just after seed dissemination. Under the preferred (light and alternating temperature) conditions, UD germinated quickly and percentage germination was high (99%), whereas UL and UP germinated moderately to slowly (65.2 and 23.8%, respectively) and the remaining seeds were primarily dormant. When the seeds were exposed to unsuitable conditions for germination, secondary dormancy was induced in all three Ulmus species. Because primary and secondary dormancy of these species was not strict, the existing dormancy could be released by moist conditions and low temperature during the winter. Thus, all three Japanese Ulmus can germinate either just after seed dissemination or in the following spring. Nevertheless, the predominant germination of summer-fruiting UD just after seed dissemination seems to be advantageous for finding safe sites that might become available after a large-scale fluvial disturbance. Similarly, the delayed germination of autumn-fruiting UP until the following spring seems to be advantageous for preventing germination at the end of the growing season. Summer-fruiting UL had a more negative response to favorable light conditions just after seed dissemination, which seems to be advantageous for establishment in canopy gaps. These germination traits seem to be adaptive responses to the dominant disturbance regimes of their natural habitats.     

马尾松雄球花生长发育特性及花粉采收特点

马尾松(Pinus massoniana Lamb.)在我国松属(Pinus)树种中分布最为广泛,其适应性强、生长快,是一种多功能、多用途、高效益的树种.除生产木材、采割松脂、培养茯苓等外,还可生产大宗的松花粉.     

Effect of sowing date on seedling emergence of species with seeds enclosed in a stony endocarp

The aim of the present study was to investigate the effect of the natural sequence of temperature conditions between the time of seed sowing and their germination on dormancy release of Prunus avium, P. mahaleb, P. divaricata, P. laurocerasus, P. spinosa, Cornus mas, C. sanguinea, and Celtis australis seeds which are enclosed in a hard stony endocarp. According to their collection date, the seeds (with the endocarp) of the above species were sown outdoor in summer, autumn, and winter and the number of emerged seedlings was counted during the following two springs. For all species, the first sowing date was immediately after seed collection and cleaning. In all species, seedling emergence occurred in early spring and dormancy was released only after the exposure of seeds to specific season conditions. The exposure of seeds of all studied species, except C. australis, to a period of warm temperatures prior to winter was necessary for dormancy breaking and germination. Autumn sowing of P. laurocerasus and C. sanguinea seeds, which were collected in summer, and the sowing immediately after seed collection of the rest species, resulted in a maximum percentage of seedling emergence in the following spring.     

Neuropharmacological activities of phytoncide released from <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>

Forest-air bathing and walking (shinrin-yoku) is beneficial to human heath. In this study the phytoncide (volatile compounds) released from Cryptomeria japonica plantation forest was characterized by using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). The main volatile compounds were α-pinene (19.35%), β-myrcene (16.98%), d-limonene (15.21%), and γ-muurolene (7.42%). Furthermore, the neuropharmacological activity of the essential oils from leaves of C. japonica (ECJ) was evaluated by several animal behavior tests. ECJ could prolong the sleeping phase of ICR (imprinting control region) mice in the pentobarbital-induced sleeping time model. Furthermore, both EJC and one of its monoterpenes, d-limonene, possessed potent anxiolytic and analgesic activities based on the results obtained from elevated plus maze and writhing tests. The volatile compounds released from C. japonica provide relaxing and stress-relieving effects on mice, and further study on the effect of phytoncide on humans is worthwhile.     

Effects of stand density on the productivity ofCryptomeria japonica male flowers

We have studied male flower production and relative illumination in clonal sugi (Cryptomeria japonica) forests planted at densities of 1,500/ha, 3,000/ha, and 5,000/ha, to clarify the effects of forest management on male flower production. Both the relative illumination and male flower production decrease as the stand density increases. The lowest position at which male flowers are formed decreases as the density of the stand decreases. High thinning intensity promotes male flower production and light pruning is ineffective to reduce male flower production. Therefore, traditional management methods used in sugi forests (i.e. planting at high density, frequent light thinning, intensive pruning and short rotation) are ideal strategies for limiting male flower production.     

Field trial of salad oil application for the induction of male flower browning ofCryptomeria japonica

A field trial of salad oil application for the induction of male flower browning ofCryptomeria japonica was conducted. The browning effect of salad oil applied from a helicopter was found to vary from clone to clone depending on the earliness of male flower development. When applied at the flower initiation stage, salad oil turned male flowers to a brown color; when applied later, the browning effect of salad oil was not clear. The effectiveness of the application depended on how close to the time of flower initiation it occurred. The harmful changes caused by salad oil solution were only observed on the leaves of Japanese plume-grass (Miscanthus sinensis), and no other effects on other plants were observed. Todd Davies for his warm hearted advice on English composition.     

Decomposition and nutrient release from leaves,twigs and roots of three alley-cropped tree legumes in central Togo

The decomposition of leaves, twigs and roots of two diameter classes (<1.5 mm, 1.5–5 mm) were examined in an alley cropping experiment withGliricidia sepium, Calliandra calothyrsus andSenna sianea in the subhumid savanna of Central Togo using the litterbag technique. The effect of the application of leaves and twigs as mulch or green manure was examined. Gliricidia showed the most rapid mass loss. For all species, leaves decomposed faster than roots. Twigs had the lowest decomposition rate except forCalliandra. The two diameter classes of roots decomposed differently in the three species:Gliricidia fine roots decomposed faster than its coarser root fraction, the coarse roots ofSenna decomposed faster than the fine roots.Termites influenced the mass loss of twigs and roots to varying extents for the different species. In the case of twigs this was markedly influenced by the mode of application: green manure showed more termite frass than mulch.Nutrient release resembled the mass loss patterns of the prunings except for K, which was leached independently from mass loss. The release of the different nutrients was in the order CaGliricidia andSenna seemed to be best for mulch and green manure production at our site.     

Pistil development in 2 types of flowers of Xanthoceras sorbifolia

In order to investigate flower development and female abortion during sex differentiation of Xanthoceras sorbifolia, anatomical observations and comparative study on differential proteins were carried out in different developmental stages of two types of flowers of this species. It was found that the selective abortion happened in male flower before the formation of megasporocyte. Special proteins related to the female abortion were found through 2-dimensional electrophoretic analysis. Protein A1 (14.2 kD) only existed in florescence of male flower, while B1 (13.7 kD) and B2 (18.2 kD) disappeared in that stage of male flower. They were all considered to be relative to pistil abortion of Xanthoceras sorbifolia. [Supported by the National Natural Science Foundation of China (Grant No.30070613) and Graduate Cultivation Foundation of Beijing Forestry University (Grant No.02jj001)]     

Nectar volume and floral entomofauna as a tool for the implementation of sustainable apicultural management plans in <Emphasis Type="Italic">Quillaja saponaria</Emphasis> Mol.

The objective of the present study was to quantify nectar volume and secretion dynamics in Quillaja saponaria Mol. and the entomofauna associated with its flowers, as a tool for the implementation of sustainable apicultural management plans. Nectar was collected daily throughout the flowers’ lifetime, three times per day at 4-h intervals. For the identification of insects associated with flowers, 5-min observation periods were carried out for 170 min in total, and a list of registered species was prepared. Within the inflorescence, central hermaphrodite flowers and lateral male flowers lived 12.3 ± 0.26 and 5.8 ± 0.26 days on average, respectively. Nectar production increased from day 1 to day 11, and then decreased until day 15. The average volume of nectar secreted per tree was 5.3 l, which would be equivalent to 4.2 kg of honey. Forty-one species of flower visitors were registered in total.     

Efficiency of extracting microarthropods from the canopy litter in a Japanese cedar (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis> D. Don) plantation: a comparison between the washing and Tullgren methods

We compared the efficiency of washing versus the Tullgren method for extracting microarthropods from dead leaves and branches in the canopy of Cryptomeria japonica trees. Oribatida and Collembola were consistently the numerically dominant taxa of microarthropods, but the relative abundance differed between the two extraction methods. Oribatida accounted for more than 70% of all the microarthropods collected by the washing method but less than 30% by the Tullgren method. Collembola accounted for less than 10% collected by the washing method but about 60% by the Tullgren method. The density of Oribatida was higher when collected by the washing method than by the Tullgren method, and vice versa for the density of Collembola. Our results suggest that the washing method is appropriate for collecting Oribatida and other microarthropods, whereas the Tullgren method is better for collecting Collembola from the canopy litter of C. japonica trees.