Effects of gibberellin A(4 + 7) and bark-ringing on cone initiation in mature Picea sitchensis grafts

Large numbers of cones (strobili) were induced in a 10-year-old plot of mature grafts of Picea sitchensis (Bong.) Carr. All trees injected with 20 mg GA(4 + 7) in June initiated female and male cones in the same year. This treatment increased the number of female cones per plant 12-fold above the controls, more than doubling the percentage of cones that were female. Complete bark-ringing (done in May of the previous year) showed an additive effect with GA on the number of female cones formed, but a negative interaction on the number of male cones induced. Ringing promoted male cone production most when used alone. Treatments, singly or combined, also increased the proportion of cones that were lateral, compared with the preponderance of terminal male cones in the controls. The effects were apparently not directly associated with alterations in vegetative vigor, although these occurred causing a reduction in the proportion of buds containing vegetative shoots the following year. The clones differed in most characteristics, but both sparse and prolific clones were induced to reproductive activity. Viable seed yields per tree, and notional production from seed-orchards were enhanced almost 10-fold by GA injection, and about 4-fold by bark-ringing and GA + bark-ringing.     

Seed cone abortion and full seed production in an indoor seed orchard with potted grafts of Picea abies

Abortion of seed cones and production of full seeds have been recorded in an indoor‐potted Norway spruce (Picea abies (L.) Karst.) seed orchard at Biri nursery in Norway. Seed cone buds aborted their normal development at much higher frequencies (22–45%) inside isolation bags than in an open‐air (4–12%) greenhouse environment. The grafts had been induced to flower the year prior to seed cone development. Treatment with gibberellin A_4/7 in conjunction with heat reduced the proportion of aborted, isolated flowers (13%) compared to treatment with heat alone (22%) in a clonally balanced material. The production of full seeds per cone increased from 3 in 1987 to 50 in 1991. The full seed production is discussed in relation to methods and timing of pollen forcing. It is anticipated that 1 kg of seeds could be produced annually in a 1250 m² greenhouse.     

Genetic variation in fruitfulness in a hinoki (Chamaecyparis obtusa Endl.) seed orchard and its impact on the maintenance of genetic diversity in seedlots

Genetic variation in seed/cone production among clones was studied in a hinoki (Chamaecyparis obtusa Endl.) seed orchard containing 25 plus-trees by analyzing the number of cones, the yield of cones and seeds of individual ramets for 5 successive years (1982 to 1986). There was significant variation among clones each year and parental contribution in the seed orchard. Specifically, in the years 1982, 1983, 1984, 1985, and 1986, 20% of the clones produced 37.2, 60.6, 36.0, 44.3, and 44.8% of the total cones, respectively. The size of the crop greatly influenced the parental balance in the resulting seed/cone crops. The product moment correlation coefficients and Spearman’s coefficients of rank correlation were small and insignificant between consecutive years, but large and highly significant between alternate years, suggesting the presence of carry-over effects in seed/cone production. The broad-sense heritability on a clone mean basis was 0.74 ± 0.15 for the number of cones, 0.72 ± 0.14 for the yield of cones, and 0.68 ± 0.13 for the yield of seeds. The corresponding heritabilities from analyses combined over all years were 0.24, 0.558, and 0.724, respectively. These results indicate that seed/cone production in hinoki is under strong genetic control. Several managerial measures are discussed that maintain the genetic diversity in seedlots used for reforestation, by reducing the variation in seed/cone production among clones and producing seed crops with equal contributions from all parents.     

Seed cone production enhanced by injecting 38-year-old Larix occidentalis Nutt. with GA4/7

The influence of injecting 38-year-old Larix occidentalis with gibberellin A_4/7 (GA_4/7) on seed and pollen cone production was studied in western Montana, U.S.A. Two natural stands thinned to several spacings in 1961 were chosen. The two widest spacings were used. In 1991, 60 trees selected for study at each site were randomly divided into two groups of similar DBH, half as controls and half injected in June 1991 with a solution of GA_4/7 in ethyl alcohol. The volume injected was adjusted to the DBH of each tree (60 mg per 5 cm diameter). In June 1994, half the trees treated with GA_4/7 in 1991 and half the untreated trees were injected with GA_4/7 in the same manner as before. In 1992 and 1995, seed cone production increased on GA_4/7-treated trees compared to the controls. Pollen cone production was significantly increased by GA_4/7 treatment but only at one site. Delayed effects of GA_4/7 on seed cone production was not evident in subsequent years after treatment. Foliar and shoot damage on treated trees was attributed to GA_4/7 treatment but most trees recovered completely the following year. Finally, GA_4/7 treatment did not affect cone length, potential seed per cone or filled seed per cone.     

Natural Variation in Seed Characteristics of Eastern White Pine (Pinus strobus L.)

Natural variation in seed characteristics of eastern white pine (Pinus strobus L.) trees and its relationship with the size, form, and crown class of parent trees was examined in second-growth, white pine mixedwood stands in Ontario. Cones were collected prior to and following partial harvesting of two stands during 2 years of above-average seed production. Fully enlarged seed extracted from mature cones was X-rayed to determine seed yield per cone, the percentage of sound, partially filled, and empty seed, and the sound seed mass for each tree. Variation in seed yield per cone, the proportion of sound, partially filled, and empty seed, and seed mass was much greater among individuals than between stands or seed years. The strength and significance of the relationship of seed mass with sound seed yield differed with stand and seed year. In uncut stands, seed mass was higher for trees with dominant crown class, larger live crown ratios, and smaller height to diameter ratios, suggesting tree vigour and microsite quality influence seed mass. Proportion of partially filled seeds was significantly reduced in both stands in the second year likely due to increased growing degree days during female gametophyte development. The implications of these results to natural and artificial regeneration of white pine are discussed.     

福建柏优树选择及种实表型变异研究

在调查研究福建柏资源基础上,制定了福建柏优树选择方法,于1998年6～11月和1999年7～11月在福建省福建柏自然分布区和栽培区以及湖南省道县福建柏天然林中选择出优树175株,其中从天然林中选出57株,从人工林中选出118株。这些优树总体表现较好,生长量大,平均树高、胸径、材积分别为15 49m、28 6cm和0 51263m3,树干通直圆满,树体健康,无病虫害,平均树龄为35 3a。1999年10～11月,采集到129株优树的球果,测定了各优树的种子千粒重、球果出籽率、球果重、球果长、球果宽、球果长×球果宽、球果长/球果宽和苞鳞数等8个指标,结果表明各优树在种实性状上差异比较大,差异最大的是球果重,平均单果重2 757g,变幅为1 342～4 748g,变异系数为27 86%;平均千粒重为6 378g,变幅为3 647～11 349g;平均出籽率为2 56%,变幅为1 62%～4 79%;球果大小相差较大,球果近球形但略长些。相关分析表明,优树各种实性状间的相关性大都达到极显著水平,千粒重与球果重量、大小呈密切的正相关,与出籽率、苞鳞数及球果形状关系不大;出籽率与其他种实性状间相关性很小,可能是个独立的性状;单果重与苞鳞数及球果大小呈高度的正相关关系,与球果形状没有关系。收集选出的175株优树中的162株,在福建省安溪白濑国有林场建成了全国第一个福建柏种?     

Cone and seed production from stone pine (<Emphasis Type="Italic">Pinus pinea</Emphasis> L.) stands in Central Range (Spain)

Natural regeneration of stone pine (Pinus pinea L.) stands in the Central Range of Spain can be difficult to attain. The success of this regeneration is affected by factors such as the total amount of seed available, the short dispersal ability of the pinyon, the conditions required for germination, specific problems associated with the establishment, early survival of the seedlings due to severe summer heat and drought, competition for water and mineral resources and grazing damage. This study focuses on seed availability. The amount of available seeds depends on the number and size of the cones and the number of viable pinyons within the cones. In stone pine stands, both variables show great year to year variability. Both cone and seed production, for a given year, are also conditioned by the vigour and health of the tree, its size, the condition and attributes of the stand and the loss of seed through pests or predation. In this study, the main factors which influence cone and pinyon production are identified and a multivariate model to predict annual cone and viable seed production is developed. To consider the correlation among observations coming from the same tree, stand or year, random components are included in the model. The multivariate random structure allows for future calibration of the model for a given year from a small additional sample of observations. It is important to know the total amount of viable seed produced in a stand for a given year since regeneration cuttings for Stone pine should be concentrated in high crop years.     

Variation in cone and seed characters in clonal seed orchards of <Emphasis Type="Italic">Pinus sylvestris</Emphasis>

Cone and seed characters were observed on top, middle and bottom portions of tree crown in 3 ramets/clone in three Turkish Pinus sylvestris seed orchards. Broad sense heritability (clonal repeatability), and correlations among characters were estimated. Around one quarter of the seed production occurred in the top portion, half in the middle and one quarter in the bottom portion of the crown for all orchards. The percentage of filled seeds varied little with the crown position, indicating more or less similar levels of selfing in the bottom of the crown as in the top. The seed weight was typically 11 mg. Differences were found for studied cone and seed characters among orchards and crown positions. Variation among grafts within clone was higher than among clones for most characters. The heritability was on average below 0.5 (e.g., cone diameter, number of filled seed per cone) and rarely rose above that (e.g., cone form, length/diameter; percentage of filled seed) for any individual characters. The coefficient of variation within clones was often higher than among clones. Thus, non-genetic factors seem often more important for the variation in performance of grafts than their genetic constitution. Cone form (length/diameter) was the character where the clone influence was the strongest. Cone number and cone dry weight showed significant correlations with seed characters (numbers of total and filled seed, percentage and weight of filled seeds). Significant correlation was found between seed characters.     

Elevated temperature during reproductive development affects cone traits and progeny performance in Picea glauca x engelmannii complex

Two temperature regimes were applied during reproductive development of seed and pollen cones of interior spruce (Picea glauca (Moench) Voss and Picea engelmannii (Parry) complex) to determine temperature effects on the adaptive traits of progeny. In Experiment 1, identical crosses were made on potted interior spruce using untreated pollen followed by exposure to a day/night temperature of 22/8 or 14/8 degrees C with a 12-h photoperiod during the stages of reproductive development from post-pollination to early embryo development. Frost hardiness and growth of progeny from seed produced in the two temperature treatments were measured over a 4-year period. Elevated temperature significantly affected both seed-cone development and the adaptive properties of the progeny. Seed cones exposed to the 22/8 degrees C treatment reached the early embryo stage in 53 days versus 92 days in the 14/8 degrees C treatment. Seed yields, cotyledon emergence and percent germination were also significantly enhanced by the 22/8 degrees C treatment. Progeny from seed produced in the higher temperature treatment showed significantly reduced spring and fall frost hardiness, but the elevated temperature treatment had no significant effects on time of bud burst, growth patterns or final heights. In Experiment 2, single ramets of the same clone were subjected to a day/night temperature of 20/8 or 10/8 degrees C during pollen cone development, starting from meiosis and ending at pollen shedding. The two populations of pollen were then crossed with untreated seed cones. Compared with pollen cones exposed to the 10/8 degrees C treatment, pollen cones exposed to the 20/8 degrees C treatment during development reached the shedding stage 2-4 weeks earlier, whereas pollen yields, in vitro viability and fertility (seed set) were significantly lower; however, the resulting progeny displayed no treatment differences in frost hardiness or growth after 1 year. Results suggest that seed orchard after-effects could be caused by temperature differences between orchard site and parent tree origin and that this effect acts on maternal development. Gametophytic (pollen or megagametophyte or both) and early embryo (sporophytic) selection are possible mechanisms that may explain the observed results. Although the effects are biologically significant, they are relatively small and do not justify changes in current deployment strategies for seed orchard seed.     

Variable dormancy in seed of Pinus contorta

Seeds of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) collected southwest of Grande Praire, Alberta at three different times and altitudes between August 20, 1984 and August 15, 1985 showed variable responses to stratification. The responses were related to seed ripeness, as judged through evaluations of cone moisture contents, and with the length of time that the cones had remained on the trees. Unripe seeds started to lose germination in the third year after pollination when on the tree. Mature seeds which lost germination by late fall 1984 regained it by the next fall, while most unripe seeds did not. Immature seeds increased their need for stratification over time while mature seeds did not. Seeds should be left on the tree until the end of the third year to insure maximum viability because they do not reach maturity until then.     

对球果损失造成油松良种减产的分析

调查了油松种子园、母树林良种减产的原因，主要是由于球果在生长发育过程中的大量损失；而虫害、雌花授粉不良、因缺少水肥造成的落花落果是油松球果损失的主要原因。同时提出了减少球果损失的几点技术措施。     

马尾松种子园种实害虫、害鼠的研究

经观察马尾松种子园种实害虫和害鼠的种类有２１种，严重危害的有机松瘿纹，马尾松窃蠹，芽梢斑螟，松实小卷蛾、油松球果小卷蛾、微红梢斑螟和社鼠。根据马尾松生殖发育规律，观察了 主要种实害虫、害鼠的 危害顺序及其程度。     

Promotion of cone production in potted black-spruce grafts, using gibberellins, heat-treatment and root-pruning

Potted 3-year-old grafts of black spruce [Picea mariana (Mill.) B.S.P.] at different stages of lateral shoot elongation were sprayed with different concentrations of gibberellin A_4/7 for a total of six weeks in a heated greenhouse to enhance seed-cone production. Grafts sprayed during the period of lateral shoot elongation produced significantly more seed cones but not pollen cones, while spraying initiated after the elongation did not promote any cone production. Increasing gibberellin did not increase production, but increased graft mortality when spraying was done during the period of rapid shoot elongation. Cone production was highest and mortality lowest with 200 mg l⁻¹ gibberellin A_4/7 spraying that was initiated in the middle of rapid shoot elongation. In a second experiment, potted 5-year-old grafts with or without root pruning were placed either outdoors or in a heated greenhouse during the period of lateral shoot elongation. Heat-treatment during the period of late show shoot elongation had a positive effect on pollen- and seed-cone production in 5-year-old grafts without root-pruning. A combination of heat-treatment and root-pruning appeared to have an adverse effect on cone production. Pollen viability was not affected by the treatments.     

杉木种子园种实害虫的综合治理

本文概述了杉木种子园主要种实害虫的综合治理措施。以虫情监测为基础,结合采种摘除虫害球果及强度修枝等林业技术,适时应用０．０５％溴氰菊酯油烟剂防治成虫。通过５年综合治理,使杉木种子园的球果虫害率明显下降,种子产量有较大提高,取得了明显的经济、社会和生态效益。     

影响杉木种子园良种产量的主要害虫及综合治理对策

在福建省洋口林场杉木种子园中常见的害虫有２６种，隶属７目２０科。其中杉木球果麦蛾、杉木扁长蝽和杉梢小卷蛾是影响良种产量的主要害虫。杉木球果麦蛾是中国新记录种，以幼虫危害球果的苞鳞、果轴及种子，使球果变色、干枯。杉木扁长蝽的危害及炭疽菌和散斑壳菌的侵染导致球果变色。１０月受害果率达３７．２％。测定结果表明，球果虫害及变色明显影响每百球果的鲜果重、种子重、千粒重及出籽率（平均下降２６．９％—７３．７％），但对种子的发芽率及涩籽率无显著影响，并提出以摘尽球果为主的综合治理措施。     

Seed-cone receptivity and seed production potential in white spruce

Three to five ramets were selected from each of five white spruce clones for the study. Seed cones (megastrobili) were pollinated once and some were sampled at the different stages of development to study the pollination mechanism, seed-cone receptivity, and seed production potential.The proximal end of a seed cone emerged from the bud scales and was the area to be receptive first. As the seed cones continued to develop, the margins of the cone scales became reflexed to increase the surface area and to funnel pollen along the margins of two adjacent scales onto the micropylar arms. Pollen was transferred to a deep depression in the nucellus and it germinated in the depression a weel after pollination. Another week later the micropyle was sealed by the ingrowth and divisions of the cells in the micropylar canal. Receptivity of a seed cone lasted for about 10 days and the end of receptivity was signalled by the closure of cone scales.The optimal receptivity appeared to occur when seed cones approached the end of receptivity and this coincided with the peak of pollen shedding. It was evident that seed cones pollinated at this stage produced the most filled seeds, an average of 41.6 from a seed production potential of 88 seeds per cone. Total cone scales averaged 67.7 per cone of which 43.6 scales were fertile and located at the mid-portion of a cone.     

马尾松母树林种子产量预测方法的研究

１９９２－１９９４年在福建省清流县灵地马尾林母树林中研究了预测球果和种子产量的可见半面树冠法、信息段法和球果切开法。结果表明，上述方法均能较好地预测马尾松母树林的球果和种子产量，且操作简便、精度高。但由于本文调查对象为结实初期的母树，还需要在推广应用中对拟合方程进一步验证和补充。     

Effects of crown-pruning on seed and pollen cone production in two lodgepole pine seed orchards in British Columbia

The effects of top pruning on subsequent seed and pollen cone production in lodgepole pine (Pinus contorta Dougl.) grafted clones in two seed orchards were evaluated. In the older orchard (14 years old), three pruning regimes were applied: an untreated control, a moderate pruning where 25% of the crown was removed and a severe pruning where 40% of the crown was removed. In the younger orchard (ten years old), only a control pruning and a severe pruning (50% of crown removed) were applied. Five-year seed cone production was lower in treated ramets compared to controls in both orchards. However, when cumulative seed cone yields were adjusted for reduced tree heights after pruning, differences were no longer significant in the older orchard. Strong clonal variation was observed in seed cone yields in both orchards. Pollen cone development was less variable among treatments in the older orchard. In the younger orchard, controls consistently produced heavier pollen crops. Pruning recommendations for similar orchards are made and results discussed for reducing the impacts of losses in seed cone yields.Deceased     

马尾松开花结实规律的初步研究

马尾松开花结实习性及球果丰歉规律,是良种生产的主要研究内容之一。例如幼林期初始开花结果年龄、雌雄球花的比例;成林期的结实数量、年度之间的差异以及球果在树冠层的分布情况;立地条件对林木开花结实的影响等问题,无论是实生种子园还是无性系种子园甚或采种母树林,都应当有所了解,掌握规律以指导园地管理与种子采收。探明这些问题不仅对于良种生产,同时在杂交育种等科研工作方面也是必不可少的。为此,我们对实生马尾松开花结实规律进行了初步研究,现总结如后。     

Effects of gibberellin A<Subscript>4/7</Subscript>, 6-benzylaminopurine and chlormequat chloride on the number of male and female strobili and immature cones in Chinese pine (<Emphasis Type="Italic">Pinus tabuliformis</Emphasis>) with foliar sprays

Three kinds of plant growth regulators, gibberellinA 4/7 (GA 4/7 ), 6-benzylaminopurine (BA), and chlormequat chloride (CCC), were evaluated for their ability to promote strobilus and cone production in a Chinese pine (Pinus tabuliformis Carr.) clonal seed orchard. Treatments (0, 250, 500, or 1000 mg L -1 ) were applied during three periods (June- July, July-August and August-September) in 2005. Of the three plant growth regulators, GA 4/7 was the best for promoting flower and cone production. Trees sprayed...