Wood structure and production within the trunk and branches of Piceasitchensis in relation to canopy formation

1979 ◽  
Vol 9 (3) ◽  
pp. 406-427 ◽  
Author(s):  
M. P. Denne

The seasonal progress of wood production and variation in tracheid dimensions were followed systematically along the trunk and main branches of Piceasitchensis trees and analysed in relation to the distribution of light intensity and leaf weight as the canopy develops. The aim was to provide data towards building models to predict effects of management on within-tree patterns of wood production and structure. Tracheid production began earliest at the tips of branches towards the base of the crown; the data show that tracheid production in the main stem began earliest several internodes below the leader, its onset progressing faster and having a shorter distance to travel down the upper branches. Tracheid production appeared to cease simultaneously throughout the trunk in codominant trees; it ceased earlier in severely suppressed trees, which consequently produced little or no latewood.In the main stem, maximum ring width occurred at least one internode above that carrying maximum total leaf dry weight. Maximum rate of tracheid production occurred one or two internodes above those having maximum current leaf dry weight, several internodes above the maximum total leaf weight. In branches, rate of wood production was closely correlated with light intensity.The seasonal increase in wall thickness from early- to latewood occurred more rapidly as you progress down the main stem to below the crown in 16-year-old trees; hence, Mork latewood began progressively earlier lower down the stem; this pattern was not developed in the trunk of younger trees. In all branches, latewood began earlier at the base than at the tip, owing to a more rapid seasonal increase in wall thickness towards the branch base. Tracheid diameter increased from the leader down to midcrown. In branches, partial correlations suggest that tracheid diameter varied with light intensity at the tip but inversely with whorl number at the branch base.

1985 ◽  
Vol 15 (1) ◽  
pp. 56-65
Author(s):  
Richard S. Dodd

To quantify patterns of wood formation in sycamore (Acerpseudoplatanus L.), the seasonal progress of wood production and structure was followed systematically throughout the outer growth sheath of the main stem and major branches. These data were considered in relation to the profile of leaf dry weight down through the crown in 8- and 12-year-old trees at stages before and after canopy closure, respectively. Mature fibre production was earliest towards the tips of the branches of the midcrown, and spread basipetally along the branches. In the main stem, mature fibre production was earliest at the tip and spread down the tree, taking about 10 days to reach the base of both pre- and post-canopy closure trees. In the stem, later fibre production down the tree was offset by later cessation of fibre maturation basally. Branch data suggested that the pattern of cessation may depend on the branch position, because cessation was latest at the base of the upper branches and at the tip of the lower branches. The maximum rate of fibre production was in the upper stem, several internodes higher than the internode bearing maximum leaf dry weight. Despite this, ring width increased down the stem, presumably as a result of the increased duration of fibre production and increased cell size. Within growth rings, vessel size remained nearly constant before declining sharply towards the end of the ring. Trees with narrower growth rings tended to have more of their ring occupied by declining vessel size suggesting a slight inverse relationship between ring width and specific gravity. Specific gravity increased down the outer growth sheath of the stem, and this increase was associated with systematic trends in fibre and vessel dimensions, together with changes in the relative proportions by area of the different tissues. Although some anatomical characters appeared to vary with the profile of the crown, others appeared to be independent of crown profile.


1990 ◽  
Vol 20 (11) ◽  
pp. 1732-1738 ◽  
Author(s):  
P. W. West ◽  
K. F. Wells

A model was developed to estimate total leaf dry weight of individual standing trees of Eucalyptusregnans F. Muell. in even-aged, monoculture stands aged 8–20 years. Tree biomass data were collected for a sample of 42 trees from four plots at three sites in Victoria and Tasmania. One plot had been heavily thinned 10 years prior to sampling. The model was based on the pipe model theory, L(x) = as(x)p(x), where L(x) is leaf dry weight above some height (x), s(x) and p(x) are, respectively, stem sapwood area and permeability at x, and a is a parameter. Permeability is known to vary with site and tree conditions, and an empirical model was developed that replaced ap(x) in the pipe model theory with a function in terms of tree age, diameter at breast height over bark, and distance along the stem from the tip of the tree. The resulting model to predict leaf weight appeared to be unbiased across sites, among trees within sites, and with respect to thinning treatment. It was found that given a prediction from the model of total leaf dry weight of one tree, it could be assumed with 95% confidence that the true value of leaf weight fell within an interval bounded by values of −60 to +76% of the estimate. When the model was used to predict stand leaf weight by summing estimates from many individual trees, the interval was bounded by minimum values of −3 to +19% of the stand estimate. These errors of estimate were probably conservative. It appeared that errors of similar magnitude may apply to other published models of this type.


2018 ◽  
Vol 15 (2) ◽  
pp. 40-51
Author(s):  
M A Hossain ◽  
M A Hasan ◽  
S Sikder ◽  
A K M M B Chowdhury

An experiment was carried out to evaluate the leaf characteristics and yield performances of mungbean (Vigna radiata L.) under different light levels at the Crop Physiology and Ecology Research Field of Hajee Mohammad Danesh Science and Technology University, Dinajpur during March to June 2016. The experiment was laid out in a split plot design with three replications. Three light levels (L100 - 100 % light intensity, L75- 75 % light intensity and L50- 50% light intensity) were assigned in the main plots and four varieties (BARl Mung-6, BINA Mung-8, BINA Mung-5 and BU Mug-4) were assigned in subplots. Mosquito nets of different pore size were used for maintaining 75 and 50 percent light intensity. Leaf area was increased due to reduced light levels in all mugbean varieties but the increment was significant in BINA Mung-5 and BINA Mung-8 only at 75% light intensity at 40 days after sowing and only in BARI Mung-6 with L50 and BU Mug-4 with L75 and L50at 50 days after sowing. Due to reduced light levels, leaf dry weight was affected more in BINA Mung-5 and BU Mug- 4 than BARI Mung-6 and BINA Mung-8. Leaf thickness was reduced under shade in all the mungbean varieties, except in BU Mug-4 at 75% light intensity, and the reduction in leaf thickness was mainly due to the reduction in thickness of spongy layer. The palisade layer thickness was influenced insignificantly but spongy layer thickness was increased in BINA Mung-5 at 100% light intensity. The grain yields (t ha-1) of BARI Mung-6 and BINA Mung-8 remained stable under partial shade condition but the grain yield of BINA Mung-5 and BU Mug-4 was reduced drastically under partial shade condition. Higher leaf dry weight, number of pods plant-1, seeds pod-1, and heavier grains in BARI Mung-6 and BINA Mung-8 contributed to the higher grain yield plant-1 under partial shade condition than in BINA Mung-5 and BU Mug-4.The Agriculturists 2017; 15(2) 40-51


2016 ◽  
Vol 3 (1) ◽  
pp. 17
Author(s):  
. Djumali

<p>Hasil dan mutu tembakau temanggung merupakan hasil interaksi pengaruh genetik tanaman dan kondisi ling-kungan tumbuh. Pada tembakau virginia, peubah-peubah agronomi tanaman merupakan karakter genetik ta-naman yang mempengaruhi hasil dan mutu. Pada tembakau temanggung, hal ini belum diketahui. Penelitian yang bertujuan untuk memperoleh peubah agronomi sebagai karakter genetik tembakau temanggung dan ka-itannya dengan hasil dan mutu rajangan kering dilakukan di rumah kaca Balittas, Malang sejak Maret–Agus-tus 2008. Sembilan kultivar tembakau temanggung disusun dalam rancangan acak kelompok yang diulang ti-ga kali. Pengamatan dilakukan terhadap peubah agronomi yang dimulai pada saat pemangkasan sampai pa-nen akhir. Hasil penelitian menunjukkan bahwa peubah agronomi yang meliputi tinggi tanaman, sudut daun, luas daun, jumlah daun, bobot spesifik daun, luas daun per helai, bobot kering tanaman, bobot kering tajuk, bobot kering akar, rasio tajuk/akar, bobot kering batang, bobot kering daun, bobot kering bunga, dan bobot kering tunas samping merupakan karakter genetik tembakau temanggung. Karakter agronomi tersebut mem-pengaruhi hasil dan mutu rajangan kering dengan total pengaruh masing-masing sebesar 92,8% dan 76,7%. Lima karakter agronomi utama yang mempengaruhi hasil rajangan kering adalah luas daun per helai, jumlah daun, bobot spesifik daun, tinggi tanaman, dan bobot kering daun dengan total pengaruh sebesar 89,4%. Adapun lima karakter agronomi utama yang mempengaruhi mutu rajangan kering adalah luas daun, rasio tajuk/akar, bobot kering tanaman, bobot kering bunga, dan tinggi tanaman dengan total pengaruh sebesar 75,7%.</p><p> </p><p>The yield and quality of temanggung tobacco are influenced by plant genetic and growth environmental. In virginia tobacco, plant agronomic variables were genetical characteristics determining yield and quality. The effect of agronomical characteristic on yield and quality of temanggung tobacco is not yet well defined. The research which aim to find plant agronomical variables as genetic characters and its relationship on dry slice and quality of temanggung tobacco, was conducted in glass house of IToFCRI, Malang from March–August 2008. Nine cultivars of temanggung tobacco were arranged in randomized block design and three replica-tions. The results showed that agronomic variables i.e. plant height, leaf angle, leaf area, number of leaf, spe-cific leaf weight, leaf area per strand, plant dry weight, shoot dry weight, root dry weight, shoot/root ratio, bast dry weight, leaf dry weight, flower dry weight, and sucker dry weight were genetic characters of temang-gung tobacco, which had effect on yield and quality with total effect of them were 92.8% and 76.7% res-pectively. Leaf area per strand, number of leaf, specific leaf weight, plant height, and leaf dry weight were agronomical characteristics which had significant effect on dry slice yield of 89.4%. Leaf area, shoot/ root ra-tio, plant dry weight, flower dry weight, and plant height were agronomical characteristics which had signi-ficant effect on quality of 75.7%.</p>


Helia ◽  
2015 ◽  
Vol 38 (62) ◽  
pp. 109-120 ◽  
Author(s):  
Vikrant Tyagi ◽  
S. K. Dhillon

AbstractNine new cms analogues on the base of diversified cms sources were developed and evaluated for morphological, agronomic, physiological and biochemical traits, including the field resistance to the prevalent diseases of sunflower under Punjab conditions. As a result of this study, the most prospective cms analogues were designated for future use in hybrid breeding programme. The results revealed that selection for tall plants with large head size and high chlorophyll content may be associated with high grain yield as well as oil content and high oleic acid content in sunflower. Leaf dry weight, biological yield, harvest index, specific leaf weight and relative leaf water content had direct positive effect on grain yield. The harvest index, specific leaf weight/plant, leaf area index and leaf area had indirect effects (through leaf dry weight) on grain yield. These traits are advocated as selection criteria for grain yield improvement in sunflower.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 635-639 ◽  
Author(s):  
Kent E. Cushman ◽  
Muhammad Maqbool ◽  
Patrick D. Gerard

American mayapple (Podophyllum peltatum L.) is a rhizomatous herbaceous perennial found in wooded areas of eastern North America and is a source of the pharmaceutical compound podophyllotoxin. To explore the possible domestication of this species, this research examined strategies for establishing mayapple in field plantings using organic mulches. Mayapple rhizome segments were harvested from the wild and transplanted to raised beds in northern Mississippi in Fall 2001. Two types of mulch (pine bark or wheat straw), two depths of mulch (7.5 or 15 cm), and two planting depths (0 or 5 cm) of rhizome segments were examined in a factorial arrangement and randomized complete block design. Data were recorded during spring of 2002 and 2003. Shoot number was not affected by mulch depth, but there was a significant interaction between mulch type and rhizome planting depth. Rhizome segments planted 0 cm deep and covered with straw mulch produced about 30% fewer shoots compared to any of the other treatment combinations. Number of emerging shoots was also affected by year, with a 33% increase in shoots from 2002 to 2003. Total leaf area and total leaf dry weight were not affected by mulch depth, but there was a significant three-way interaction between mulch type, rhizome planting depth, and year. During 2002, treatment combinations were not different, but during 2003 rhizome segments planted 0 cm deep and covered with straw mulch produced less leaf area and leaf dry weight than any of the other treatment combinations. The ratio of sexual shoots to total shoots was affected by year, with a higher ratio of sexual shoots occurring in 2002 than 2003. Grasses established in bark mulch to a greater extent than in straw mulch in 2002, but weed control was excellent for all treatments in 2003. These results indicate that rhizome segments planted 0 cm deep and covered with straw mulch consistently produced fewer shoots with less leaf area and dry mass compared to any other treatment combination. We preferred bark mulch, but we can recommend either bark or straw mulch for the purpose of establishing field plantings of american mayapple in full sun as long as rhizome planting depth is 5 cm. There was no difference between the two mulching depths used in this study; therefore, a mulch depth of 7.5 cm can be recommended because of its lower cost.


1960 ◽  
Vol 55 (1) ◽  
pp. 35-46 ◽  
Author(s):  
A. H. Bunting ◽  
B. Anderson

A study, using the methods of growth analysis, is reported of the accumulation of dry matter in two Natal Common groundnut crops grown at Kongwa, Tanganyika under conditions of relatively low population (26,000 plants/acre) with phosphate fertilizer (F series), and at a higher population (56,000 plants/acre) without fertilizer (O series). The uptake and distribution of N, P, K, Mg and Ca was followed in the F series.In the F series, the dry weight per plant at maturity was 32·7 g., of which 14·9 g. (45%) was kernels, while in the O series the corresponding figures were 20·6 and 10·4 g. The relative growth rates, net assimilation rates and leaf-area ratios were similar in the two crops, with small but consistent advantages to the F series. Nevertheless, the yields per acre were markedly higher in the O series, where total dry-matter and kernel yield were 2540 and 1290 lb./acre, respectively, against 1910 and 870 lb. in the F series. It is shown that this was the result of consistently higher leaf weights per acre and a higher total leaf-weight duration (4180 lb. weeks/acre) in the O series than in the F series, where total leaf weight duration was 2810 lb. weeks/acre.The formation of the kernels continued to maturity in each case, largely at the expense of current assimilation rather than by net translocation from the vegetative parts.The uptake of N, in the F series, reached a total of 63 lb./acre, of which 45 lb. was in the mature kernels. It went largely into the vegetative parts during the first two-thirds of the crop's life, but in the final stages most of the uptake went into the kernels and there was some evidence of translocation of N from the vegetative parts and the shells. N accumulation did not seem to be affected by rainfall fluctuations within the season. The net assimilation rate did not appear to be directly associated with the activity of the plant in accumulating N, but the leaf-area ratio, and the relative growth rate, were associated with the rate of N uptake per unit of plant dry weight.The total P taken up was no more than 4 lb. (of the element) per acre of which nearly 80% was found in the kernels at maturity. There was considerable evidence of translocation of P into the kernels from the vegetative parts of the plant. P uptake (unlike that of N) was heavily reduced in a mid-season dry period, suggesting that P was largely derived from the upper layers of the soil.The total amount of K found in the crop at maturity was about 26 lb./acre, mostly in the vegetative parts. Rather under a fifth was in the kernels, although they constituted 45% of the total dry weight. The data for Ca and Mg are incomplete, but it may be suggested that the maximum accumulation of Ca was around 10 lb./acre, almost all in the vegetative parts, and that of Mg about 5 lb./acre, of which 2 were in the kernels.The grateful thanks of the authors are due to Dr M. T. Friend, of the East African Agriculture and Forestry Research Organisation, Muguga, Kenya, who determined N and P in the samples of the F series, and to Mr G. T. Chamberlain, of the same Organisation, who carried out the estimations of K, Ca and Mg. They would also wish to express their indebtedness to the members of the former Scientific Department of the Overseas Food Corporation who assisted with the work in laboratory and field, and in particular to Mr B. W. Culy, Manager of the Kongwa Experimental Station, who was responsible for the production of the crops.


1992 ◽  
Vol 117 (2) ◽  
pp. 216-219 ◽  
Author(s):  
Asiah A. Malek ◽  
Frank A. Blazich ◽  
Stuart L. Warren ◽  
James E. Shelton

Seedlings of flame azalea [Rhododendron calendulaceum (Michx.) Torr] were grown for 12 weeks under long-day conditions with days at 18, 22, 26, or 30C for 9 hours in factorial combination with nights at 14, 18, 22, or 26C for 15 hours. Total plant dry weight, top dry weight, leaf area, and dry weights of leaves, stems, and roots were influenced by day and night temperatures and their interactions. Dry matter production was lowest with nights at 14C. Root, leaf, top, and total dry weights were maximized with days at 26C in combination with nights at 18 to 26C. Stem dry weight was maximized with days at 26 to 30C and nights at 22C. Leaf area was largest with days at 18 and 26C in combination with nights at 18 or 26C. Within the optimal, day/night temperature range of 26 C/18-26C for total plant dry weight, there was no evidence that alternating temperatures enhanced growth. Shoot: root ratios (top dry weight: root dry weight) were highest with days at 18 and 30C. Leaf area ratio (total leaf area: total plant dry weight) was highest and specific leaf area (total leaf area: leaf dry weight) was largest when days and nights were at 18C and were lower at higher temperatures. Regardless of day/night temperature, leaf weight ratio (leaf dry weight: total plant dry weight) was higher than either the stem weight ratio (stem dry weight: total plant dry weight) or root weight ratio (root dry weight: total plant dry weight). Net leaf photosynthetic rate increased with day temperatures up to 30C.


1962 ◽  
Vol 40 (10) ◽  
pp. 1299-1311 ◽  
Author(s):  
D. J. C. Friend ◽  
V. A. Helson ◽  
J. E. Fisher

The area of a fully-grown leaf lamina varied according to its position on the stem, and the temperature, light intensity, and photoperiod under which the plant was grown.In continuous illumination, raising the temperature by 5° intervals between 10 and 25 °C, resulted in progressively higher rates of leaf initiation, emergence, and expansion. The length of the lamina increased with each increase in temperature, but the breadth and thickness decreased. The greatest area of individual leaves was formed at 20 °C. Each increase in light intensity over the range 200, 500, 1000, 1750, and 2500 ft-c resulted in higher rates of leaf initiation, emergence, and expansion, and increases in breadth and thickness, but a decrease in length. The greatest area was formed at 1000–1750 ft-c.An increase in daylength from 8 to 24 hours increased leaf length, breadth, and area. This was a photoperiodic effect, unlike the increase in thickness with increased daylength, which was related to the total light energy received.Changes in leaf shape under different environmental conditions were not directly related to changes in leaf dry weight. A control of leaf growth by hormonal mechanisms sensitive to photoperiod seems more probable than does control by internal competition for assimilates among developing leaves.


1970 ◽  
Vol 36 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Sebahattin Albayrak ◽  
Necdet Çamas

Changes in plant growth viz. leaf area, leaf weight ratio, root weight ratio, dry leaf weight, dry root weight, total plant dry weight, specific leaf area, leaf thickness, leaf area ratio, net assimilation rate and relative growth rate due to the effects of environmental conditions such as temperature and light intensity were described by plant growth models. All equations produced for growth parameters were affected by light intensity and temperature. From multi-regression analysis, close relationships were found between actual and predicted growth parameters. The regression coefficients (r²) of the equations for growth parameters varied from 0.95 to 0.99 for cultivar Ecdogelb and 0.83 to 0.99 for cultivar Ecdorot, respectively.  


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