Variation in cone morphology, seed traits and germination behaviour of Cedrus deodara a study of Bhaderwah forest division (Jammu and Kashmir), India

We analyzed 17 seed sources (seed stands) of Pinus wallichiana for variations present in cone and seed characters, scattered over natural distribution in north-west Himalayan states (Uttarakhand and Himachal Pradesh) of India. The significant variations were observed in cone weight, cone length, cone width, seed length, seed width, seed weight, seed germination, radicle length, and plumule length among different seed sources of the species. Significant positive correlation between seed weight, cone weight and cone width showed that seed weight in the species depend more on the cone size. Seed germination was also positively correlated with seed weight, cone weight and radicle length in the study. The estimates of variability with regard to genetic parameters for seed weight, seed germination, cone length, cone width, cone weight showed wide range of variation in the study. Seed weight showed high heritability values coupled with maximum genetic gain. Traits with such values indicate presence of good amount of heritable additive components and are under strong genetic control. The findings of the study revealed that seed sources expressed both phenotypic and genotypic differences in the seed and cone traits which might be due to the differences in genetic make up of various seed sources and environmental factors i.e. genotypic and environmental interaction. The study suggests that the seed weight should be given the top priority for the further improvement of this species.

The allelopathic potential of Euphorbia helioscopia L. was investigated against Brassica campestris L. and Triticum aestivum L. in the laboratory. Fresh and dry leaves of Euphorbia helioscopia of 5g, 10g and 15g weight were soaked in 100ml of distilled water. These materials were filtered after 24 and 48 hours. The extract of fresh and dry leaves of Euphorbia helioscopia was applied in 5g, 10g and 15g concentration on Brassica campestris and Triticum aestivum in order to investigate the allelopathic impact on radicle and plumule length and germination percentage after 72hrs of incubation period at 26°C. The results showed that the dry and fresh leaves extract of Euphorbia helioscopia significantly reduced plumule and radicle length of both test species while stimulated the germination percentage in Brassica campestris and Triticum aestivum as compared to the control. The inhibitory effect of dried leaves on the test plant was more conspicuous than the fresh leaves. The plumule length was inhibited more in Brassica campestris as compared to Triticum aestivum by dry leaves and was recorded 95.49% and 61.57% in 24 hours soaking extract at 10g concentration and 94.83% and 54.43% in 48 hours soaking extract at 15g concentration. The radicle length B. campestris as compared to Triticum aestivum was effected more by 24 hours soaking extract and was recorded 93.57% in 10g fresh leaves and 15g dry leaves extract. The germination percentage of Triticum aestivum was stimulated by 24- and 48-hours soaking extract at all concentrations of fresh and dry leaves extract. As compared to Triticum aestivum, Brassica campestris was more effected by all treatments. From the result, it was concluded that the dry and fresh extract of Euphorbia helioscopia negatively affected the growth of Brassica campestris and Triticum aestivum and stimulated the germination of Triticum aestivum which suggests that some allelochemicals might be present in Euphorbia helioscopia. Keywords: Allelopathy; Brassica campestris; Euphorbia helioscopia; Germination percentage; Inhibitory effect; Plumule length; Radicle length; Triticum aestivum http://dx.doi.org/10.19045/bspab.2020.90162

اسطوخودوس راست جزء گیاهان دارویی اسانس‌دار از خانواده نعناع و بومی ایران می باشد و به صورت سنتی و صادراتی در درمان درد مفاصل، دل‌پیچه و زکام کاربرد دارد. به منظور بررسی اثر پیش تیمار اسیدسالیسیلیک بر جوانه زنی بذر اسطوخودوس راست، در سطوح یکسان تنش شوری و خشکی دو آزمایش در قالب طرح کاملا تصادفی با سه سطح اسیدسالیسیلیک (0، 1/. و 5/. میلی مولار) و چهار سطح تنش شوری و خشکی (0، 2-، 4- و 6- بار) در سه تکرار انجام شد. از NaCl وPEG به ترتیب برای ایجاد تنش شوری و خشکی استفاده گردید. نتایج دو آزمایش نشان داد که با افزایش تنش شوری و خشکی به طور معنی دار از درصد جوانه زنی، طول ریشه چه، ساقه چه و بنیه بذر کاسته شد. در زمان عدم تنش شوری و خشکی، پیش تیمار با اسیدسالیسیلیک منجربه افزایش معنی داری در صفات مورد بررسی در مقایسه با شاهد نشد. ولی با اعمال تنش شوری و خشکی در سطح 4- و 6- بار، پیش تیمار باعث افزایش معنی دار تمامی صفات مورد بررسی شد. طول ساقه چه در بین سایر صفات از حساسیت بالاتری نسبت به تنش شوری و خشکی‌ برخوردار بود. علاوه‌‌بر آن مشاهده گردید که جوانه زنی بذرهای اسطوخودوس راست تا حدودی شرایط تنش خشکی را بهتر از شرایط شوری تحمل می‌کند. در مجموع نتایج نشان داد که پیش تیمار بذر توسط اسیدسالیسیلیک در مناطق شور و خشک می تواند باعث مقاومت بذر گیاه دارویی اسطوخودوس راست در مرحله جوانه زنی شود.

جنس مریم گلی در ایران دارای 58 گونه گیاهی علفی یکساله و چندساله است که 17 گونه ی آن انحصاری بوده که یکی از آنها معروف به مریم گلی سهندی با نام علمی Boiss & Buhse Salvia sahendica است. به منظور بررسی عکس العمل جوانه‌زنی بذر این گیاه به تنش خشکی ناشی از پلی اتیلن گلایکول 6000 و همچنین تنش شوری ناشی از کلرید سدیم، دو آزمایش مستقل بر پایه طرح کاملا تصادفی با سه تکرار اجرا گردید. آزمایش اول شامل اثر سطوح مختلف خشکی (صفر، 2-، 4-، 6-، 8- و 10- بار) و آزمایش دوم شامل اثر سطوح مختلف شوری (صفر، 50، 100، 150، 200 و 250 میلی مولار) بر درصد و سرعت جوانه زنی، شاخص بنیه، طول ریشه‌چه و ساقه‌چه بود. نتایج نشان دهنده اثر معنی دار تیمارهای خشکی و شوری بر تمامی صفات مورد بررسی بود. در بررسی اثر تنش خشکی، بیشترین و کمترین درصد جوانه‌زنی در تیمار 2- بار و 10- بار (به ترتیب 11/60 و 55/41 درصد) و بیشترین شاخص بنیه در تیمار 4- بار (07/62) مشاهده شد. در بررسی اثر تنش شوری، بیشترین و کمترین درصد جوانه‌زنی در تیمار 50 میلی مولار و 250 میلی مولار (به ترتیب 61/55 و 43/12 درصد) و بیشترین شاخص بنیه در تیمار شاهد (07/54) اندازه‌گیری گردید. طول ریشه‌چه کمتر از طول ساقه‌چه تحت تاثیر تنش ها قرار گرفت. با توجه به نتایج این تحقیق به نظر می رسد مریم گلی سهندی تحمل نسبتا خوبی به شرایط تنش خشکی و شوری در مرحله جوانه‌زنی دارد.

Phenotypic variability of the cones and seeds was studied on seven larch clones that were obtained through grafting from plus trees, selected from natural and artificial populations from Romania. Also, correlations between several characteristics such as cones weight (g), cone length and width (cm), seed weight (mg), seed length and width (mm) were studied. A wide variation was observed for the weight of cones, ranged between 1.97-4.93 g, the average for all clones being 3.50 g. The coefficient of variability for cones weight oscillated, depending on the provenance, from 11.1% to 21.2%. Seeds weight varied between 54.4-74.4 mg, with a mean value of 61.9 mg. The weight of cones was positive correlated with all traits, except width of cones and seeds length. Weight of seeds was strong correlated with all traits, the biggest value of the coefficient of correlation being registered with the weight of cones (0.835). A very strong correlation (+0.939) was registered between the germination energy and germination capacity of seeds, but germination of seeds was negative linked with all traits of cones and seeds, not statistically correlated. The heritability in broad sense had high values, comprised between 0.943 (width of cones) and 0.993 (weight of cones). The results had illustrated that the peculiarities of the cones and seeds have a strong genetic determinism, influenced especially by the genotype and in a relatively small extent by the environment.

In order to evaluate the effects of methanol on germination percentage, germination speed index, plumule and radicle length, plumule and radicle dry weigh, vigor index and consumed endosperm of bean in condition of water deficit, a factorial experiment done based on completely randomized design with three replications. The first factor was different levels of methanol included 0 (control), 5, 10 and 15 volumetric percentage, and second factor was negative water deficit in four levels of 0, -3, -6 and -9 bar. Results of this study showed that there was a significant difference among different methanol concentrations regarding germination percentage, germination speed index, plumule and radicle length, plumule and radicle dry weight, vigor index and consumed endosperm (p 0.01). Different levels of methanol caused significant decrease on germination characteristics compared with control. Drought stress at -9 bar level significantly decreased germination percentage, germination speed index, radicle length, radicle dry weigh and consumed endosperm compared with other levels. Results showed that in non-stress condition, methanol levels led to significant decrease on germination characteristics compared with control. In drought stress condition, methanol levels caused significant decrease on germination percentage, plumule dry weigh, radicle length and radicle dry weight compared with control.

Seaweed extracts are used as nutrient supplements, biostimulants, or biofertilizers in agriculture and horticulture to increase plant growth and yield. In this study, we examined the effect of liquid seaweed extracts (LSEs) made from Ulva lactuca, Caulerpa sertularioides, Padina gymnospora, and Sargassum liebmannii as biostimulants on the germination and growth of tomato (Solanum lycopersicum) under laboratory and greenhouse conditions using foliar and soil drench applications of LSEs. We assessed LSEs at different concentrations (0.2, 0.4, and 1.0 %) on germination parameters (percentage, index, mean time, energy, and seedling vigor index) and growth parameters (plumule length, radical length, shoot length, root length, fresh weight, and dry weight) of tomato seedlings. Our results indicate that seeds treated with LSEs of U. lactuca and P. gymnospora at lower concentrations (0.2 %) showed enhanced germination (better response in germination rate associated with lower mean germination time, high germination index and germination energy, and consequently greater seedling vigor and greater plumule and radicle length). Application as a soil drench was found to be more effective in influencing the height of the plant (up to 79 cm) than the foliar spray application (75 cm). Plants receiving LSEs of U. lactuca and P. gymnospora showed increased shoot length, root length, and weight. Furthermore, U. lactuca and P. gymnospora were found to be more successful and better candidates for developing effective biostimulants to improve the growth of tomato plants. This study provides important information on the identification and utilization of Mexican seaweed resources for agriculture and is the first study to report on the uses of these seaweeds as a source of liquid extracts as biostimulants in agriculture.

The current research work investigates the allelopathic potential of leaves of most common plants found in Brassica farms i.e.Morus alba, Populus nigra and Euphorbia helioscopia on seed germination and seedling growth of Brassica campestris.Fresh and dry leaves of M. alba, P. nigra and E. Helioscopia was prepared by soaking fresh chopped leaves and dry leaves in powder form (5g, 10g and 15g) were soaked in 100ml of distilled water for 48hrs and were filtered after 24hrs.The extract of M. alba, P. nigra and E. helioscopia was applied on B. campestris seeds to study its effect on germination percentage, radicle length and plumule length.The data was recorded in triplicates after 72hrs of the incubation period at 26ºC.Extracts of M. alba and P. nigra significantly reduced the germination percentage while E. helioscopia enhanced the germination percentage of B. campestris.The results revealed that the most effective treatment was 10g fresh leaves extract of P. nigra which reduced the germination to 67% and showed no germination in 15g fresh leaves extract.The fresh and dry leaves extract of M. alba, P. nigra and E. helioscopia reduced the radicle and plumule length.Maximum reduction in the radicle length was recorded 95.41% in 10g fresh leaves extract of Populus nigra and maximum reduction in plumule length was recorded 95.49% in 15g dry leaves extract of Euphorbia helioscopia.The effect of dry leaves extract was more inhibitory effect than the fresh leaves extract.From the results it was concluded that the fresh and dry leaves extract of M. alba, P. nigra and E. helioscopia negatively affected the germination and seedling growth of Brassica campestris which indicates that some allelochemicals might be present in these plants.

In the Californian representatives of the Subsection Oocarpae (Pinus attenuata, P. muricata and P. radiata), there is variability in several cone characters. The cones range from being thin-scaled and attached to branches at relatively right angles, to having very thick scales and prominent apophyses on one side and attached to branches at acute angles. Thick-scaled cones provide more protection for the seeds from the high temperatures of fires than do thinscaled cones and may deter attacks from the squirrels Tamiasciurus and Sciurus. These cones carry fewer seeds per given weight of cone which is energetically less efficient for the squirrels to harvest. Squirrels are known to selectively feed on cones carrying more seeds per cone. Thin-scaled cones yield more seeds per given cone weight. This is energetically advantageous to reproductive success but may make them favorite targets for squirrel feeding. Consequently, individuals with thin-scaled cones can only be favored in areas where fires are not too hot and where squirrels are rare or absent. Such conditions seem to be met for pine populations on Santa Cruz, Santa Rosa, Guadalupe and Cedros Islands, and San Vicente and Ensenada, Baja California. It is precisely in these populations where cones with thin scales are most frequent. In areas where fires may be expected to be hotter and squirrels more common, individuals with thick-scaled asymmetric cones predominate. The cones of a number of pine species show a great deal of variability in cone shape, structure, scale thickness and angle of attachment to branches. This is true of jack pine Pinus banksiana Lamb. (Rudolph et al. 1957) lodgepole pine Pinus contorta Dougl. (Critchfield 1957) and the closed-cone pines of California, P. radiata D. Don P. attenuata Lemmon and P. muricata D. Don (Duffield 1951; Newcombe 1962; Forde 1964; and others). In his discussion of the genus Pinus, Shaw (1914) suggested that thick-scaled, serotinous cones, closely appressed to branches, were adaptations for protection of the

The effect of chromium on common agricultural crops (wheat, Indian mustard, sorghum, maize) was investigated and some alleviators were used to reduce chromium toxicity.Petri plate experiments were conducted in order to germinate seeds of crops.The results showed no reduction in germination up to 500 ppm but gradual decrease was observed in higher concentrations.Germination was higher in Indian mustard as compared to wheat and sorghum, however maize exhibited maximum germination.The higher chromium concentration (1000 ppm) significantly inhibited germination, plumule and radicle length.Addition of alleviators (ammonium sulphate, calcium sulphate, calcium phosphate, potassium chloride, zinc sulphate) indicated reduction in chromium toxicity.The most effective alleviator was zinc sulphate.It may be concluded that the attenuation of chromium toxicity by alleviators addition is directly attributed to its regulation on germination, and their distribution at radicle and plumule length.The present study can be used as a tool to alleviate chromium toxicity to enhance the yield of common crops in soils contaminated by chromium.

Bermudagrass (Cynodon dactylon), a salt-tolerant species surviving in environments with pH up to 9.3, and it exhibits variable germination responses under salt and alkaline stress. This study evaluates the impact of neutral and alkali salts with varying pH levels on bermudagrass seed germination. Six bermudagrass germplasm accessions were analyzed using neutral (NaCl: Na2SO4 = 1:1, pH 6.12–7.14) and alkali (NaHCO3:Na2CO3 = 1:1, pH 9.62–9.90) salt treatments. Salt concentrations ranged from 0 to 250 mmol/L, with increments of 25 mmol/L. The assessed parameters included seed germination rate, germination potential, germination index, radicle length, plumule length, seedling weight, and radicle and plumule length ratio. The salt tolerance threshold of each germplasm was calculated using a linear regression fitting model. Critical indicators of salt tolerance were selected through stepwise regression, and the salt-alkali tolerance ranking was determined using a combined membership function and discriminant analysis. The results indicated that the total score decreased with increasing salt concentration under neutral salt stress. Alkali salt stress was more damaging to bermudagrass seedlings than neutral salt stress, inhibiting germination at 50 mmol/L. Neutral salt tolerance thresholds ranged from 31.7 to 207.7 mmol/L, while alkaline salt tolerance thresholds ranged from 16.9 to 53.3 mmol/L. The six germplasm accessions exhibited different responses to salt and alkali stress. Key indicators for neutral salt tolerance included plumule length, radicle and plumule length ratio, and seedling weight. For alkali salt tolerance, key indicators were germination potential, radicle length, and seedling weight, which can be used to screen for resistant germplasms. Our study demonstrates that alkaline salts inhibit seed germination and seedling growth more than neutral salts, and pH affects root growth and the radicle-to-plumule length ratio in seedlings. This research has significant ecological implications, providing insights into the adaptation strategies of bermudagrass in salt-affected and alkaline environments, which could aid in the restoration and management of degraded ecosystems.

Alnus cremastogyne is a rapidly growing broad-leaved tree species that is widely distributed in southwest China. It has a significant economic and ecological value. However, with the expansion of the planting area, the influence of phenotypic variation and differentiation on Alnus cremastogyne has increased, resulting in a continuous decline in its genetic quality. Therefore, it is crucial to investigate the phenotypic variation of Alnus cremastogyne and select excellent breeding materials for genetic improvement. Herein, four growth-related phenotypic traits (diameter at breast height, the height of trees, volume, height under the branches) and twelve reproductive-related phenotypic traits (fresh weight of single cone, dry weight of single cone, seed weight per plant, thousand kernel weight, cone length, cone width, cone length × cone width, fruit shape index, seed rate, germination rate, germination potential, germination index) of 40 clones from four provenances were measured and analyzed. The phenotypic variation was comprehensively evaluated by correlation analysis, principal component analysis and cluster analysis, and excellent clones were selected as breeding materials. The results revealed that there were abundant phenotypic traits variations among and within provenances. Most of the phenotypic traits were highly significant differences (p < 0.01) among provenances. The phenotypic variation among provenances (26.36%) was greater than that of within provenances clones (24.80%). The average phenotypic differentiation coefficient was accounted for 52.61% among provenances, indicating that the phenotypic variation mainly came from among provenances. The coefficient of variation ranged from 9.41% (fruit shape index) to 97.19% (seed weight per plant), and the repeatability ranged from 0.36 (volume) to 0.77 (cone width). Correlation analysis revealed a significantly positive correlation among most phenotypic traits. In principal component analysis, the cumulative contribution rate of the first three principal components was 79.18%, representing the main information on the measured phenotypic traits. The cluster analysis revealed four groups for the 40 clones. Group I and group II exhibited better performance phenotypic traits as compared with group III and group IV. In addition, the four groups are not clearly clustered following the distance from the provenance. Employing the multi-trait comprehensive evaluation method, 12 excellent clones were selected, and the average genetic gain for each phenotypic trait ranged from 4.78% (diameter at breast height) to 32.05% (dry weight of single cone). These selected excellent clones can serve as candidate materials for the improvement and transformation of Alnus cremastogyne seed orchards. In addition, this study can also provide a theoretical foundation for the genetic improvement, breeding, and clone selection of Alnus cremastogyne.

اگرچه کشت زودهنگام محصولات بهاره برای استفاده از شرایط معتدل بهاری و همچنین رشد رویشی مناسب اهمیت زیادی دارد ولی وجود دماهای پایین در ابتدای دوره رشد ممکن است رشد گیاه را با تنش سرما مواجه نماید. این آزمایش به‌صورت فاکتوریل شامل شش غلظت متیل جاسمونات (صفر، 1، 5، 50، 100 و 150 میکرومولار) و سه سطح دما (8، 11 و 14 درجه سانتی­گراد) در قالب طرح کاملا تصادفی در شرایط کنترل‌شده در دانشگاه شهرکرد در سال 1395 اجرا شد. در روز یازدهم صفات مورفولوژیکی و بیوشیمیایی اندازه‎گیری شد. نتایج نشان داد که بیشترین طول ریشه‎چه در غلظت 50 میکرومولار متیل جاسمونات و دمای 11 درجه سانتی­گراد با 55.6 درصد افزایش نسبت به شاهد حاصل شد. در دمای 8، 11 و 14 درجه سانتی‌گراد بذرهایی که با متیل جاسمونات تیمار نشده بودند فاقد ساقه‎چه بودند. در دمای هشت درجه سانتی­گراد، غلظت پنج میکرو مولار بیشترین طول ریشه ­چه، طول ساقه­ چه و وزن خشک ساقه­ چه را داشت. در بین تیمارهای متیل جاسمونات، بیشترین میزان فعالیت آنزیم‎های گایاکول پراکسیداز و کاتالاز نیز در غلظت پنج میکرومولار مشاهده شد. در دمای 11 درجه سانتی­گراد، غلظت پنج میکرومولار به علت افزایش طول ساقه­ چه، وزن خشک ریشه­ چه، میزان فعالیت آنزیم کاتالاز نسبت به سایر غلظت‎ها برتری داشت و ازلحاظ طول ریشه ­چه و فعالیت آنزیم سوپر اکسید دیسموتاز در رتبه دوم قرار گرفت. در دمای 14 درجه سانتی­گراد، غلظت 50 میکرومولار دارای بیشترین وزن خشک ریشه­ چه، وزن خشک ساقه­ چه و میزان فعالیت آنزیم­ های سوپراکسیددیسموتاز، گایاکول پراکسیداز و کاتالاز بود. در دمای 14 درجه سانتی­گراد، بیشترین میزان طول ساقه ­چه و شاخص بنیه بذر در پنج میکرومولار مشاهده شد و از این لحاظ غلظت 50 میکرومولار در رتبه دوم قرار گرفت. به‌طورکلی نتیجه‎گیری می‎شود که کاربرد متیل جاسمونات باعث افزایش فعالیت آنزیم‎های آنتی‌اکسیدان و درنتیجه تحمل گیاهچه کدوی پوست‌کاغذی به تنش دمای پایین می­شود.

Chickpea is one of the new crops being grown in Zimbabwe for its plethora of benefits in crop production and human diet. However, like most grain legumes preliminary research has shown that chickpea seed has a problem of poor germination hindering the realization of the crops full potential yield. Seed priming has a potential to improve germination of chickpea. Therefore, a laboratory experiment was carried out to determine the effects of seed priming on seed germination. The experiment was laid out as a 4 × 5 factorial in completely randomised design (CRD) with 20 treatments replicated three times. The treatments investigated were five seed priming methods viz hydro-priming, halo-priming (KNO3), prechill, preheat, and no priming (control); and four chickpea varieties that were ICCV00305, ICCV03404, ICCV97105, and ICCV92944. Hydro-priming involves soaking seed for 24 hours and leaving it to dry in the laboratory for 24 hours at room temperature before it is planted. Halo-priming was done by soaking the seed in a solution with 2.4 g of potassium nitrate and 1.2 ml of distilled water. Prechill treatment involves subjecting seed at a temperature of 10°C for 7 days before planted. Preheating was done by subjecting the seed in an oven at 35° C for 30 minutes. The parameters measured were germination percent, speed of germination, radicle and plumule length, and seedling vigor index. The results showed that preheating and halo-priming chickpea seed significantly p &lt; 0.05 improved germination percentage, increased radicle and plumule length, and seedling vigor index. Hyro-priming and no priming reduced germination percentage, decreased radicle and plumule length with poor seedling vigor. Results also indicated that variety ICCCV92318 recorded the highest germination percentage, radicle and plumule length, and seedling vigor index, while variety ICCV97114 recorded the least figures on all tested parameters of chickpea. It can be concluded that preheating seed and halo-priming seed improved germination and seedling vigor in chickpea.

The study addressedthe morphometric indicators of cones and seed scales, such as length, width, and weight (before opening and after drying). Similarly, seed scales were measured, the marginal lines were described, and the number of seed scales in the cones was counted. The summary tables showed significant differences in the length and width of cones (Student's criterion). The correlation analysis was used to quantify the association between various indicators and the seed scale size. The samples were collected in the Genze Dendrological Garden, a natural landmark of regional significance. The study was carried out usingMolchanov and Smirnov’s (1967) method in the summer-autumn period. Siberian spruce (both blue and green forms), Serbian spruce, Colorado spruce (green form), and Canadian spruce had medium and large cones, which indicates a high adaptive capacity of these species. The length of cones in blue-grey and golden forms of Colorado spruce was below the average, indicating a low adaptive ability of the introduced species in the West Siberian foreststeppe. The correlation analysis showed a moderate dependence of the weight of seed scales and the weight of cones after drying (K = 0.60). A small dependence was found between the weight of seed scales and the length of cone after drying (K = 0.39). The size of seed scales strongly correlated with the size of cones (K ˃ 0.8). Student's t-test did not reveal significant differences in the width of cones in the studied species and forms of spruce, except for green form of Colorado spruce as compared to Serbian spruce and Canadian spruce, and blue-grey form of Colorado spruce as compared to Canadian spruce , showing notable differences at 1% significance point. By the length of cones, the studied species can be categorized into twoessentially different groups, the first one including all forms of Siberian spruce and Colorado spruce and the second one including Serbian spruce and Canadian spruce .