Dry Weight Increment Research Articles

Effect of lateral far-red light supplementation on the growth and morphology of birch seedlings and its interaction with mineral nutrition

The effects of lateral far-red light (FR) and nutrient supply on the growth and nitrogen accumulation of silver birch (Betula pendula) seedlings were studied with the objective of testing the following hypotheses: (1) silver birch seedlings grow taller in response to increased FR irradiance received from the side; (2) this response is modulated by the nutritional status of the seedlings; and (3) an increase in lateral FR irradiance, and concomitant decrease in red to far-red photon ratio, affects the carbon and nitrogen economies of the seedlings. Two factorial experiments, each with two levels of mineral nutrient availability and two light treatments (background 'white' light with and without additional lateral FR simulating light reflected by neighbours in a sparse canopy) were done with small seedlings. The two experiments differed in PAR irradiance. The results of these experiments were that (1) stem elongation rate was increased by lateral FR addition, (2) there was no interaction between this effect and the nutritional status of the seedlings, and (3) neither whole plant accumulation of nitrogen nor dry weight increment was affected by lateral FR under either mineral nutrient supply regime.

Mineral nutrition in carnation tissue cultures under different ventilation conditions

Growth and propagation rates, hyperhydricity percentages, macronutrientabsorption and pH evolution were evaluated in Dianthuscaryophyllus CV Nelken cultured in vitro under different ventilationconditions. Culture in well ventilated conditions (HVC) i.e. low relativehumidity, generated lower percentages of hyperhydric explants, with highermicropropagation coefficients and dry weight increments, than in less ventilatedcultures (LVC). Macronutrient absorption was similar in both types of cultures,except for ammonium, nitrate, chloride and phosphate. In LVC, after 15 days ofculture, carnation explants absorbed more nitrate than ammonium and chlorideuptake was 5 times greater than in HVC. Phosphate uptake was more pronounced inLVC after 15 days of culture, reaching similar values in both types of culturevessels at the end of the experiment, and led to growth limiting conditions formore prolonged cultures. Medium pH decreased to acid values after 15 days ofculture and even more at the end of the experiment; however, these acidconditions seem not be an obstacle for nutrient absorption.

Plant N capture and microfaunal dynamics from decomposing grass and earthworm residues in soil

Plant roots may be effective competitors with micro-organisms for the nutrients released from decomposing organic patches buried in soil. We aimed to establish whether this was because they were more effective at acquiring nutrients or simply because they represent a slower turnover pool. Over 30 days we followed decomposition of, and plant N capture from, dual labelled ( 15N/ 13C) earthworms ( Lumbricus terrestris L.) and grass ( Lolium perenne L. shoots) added as discrete patches to soil microcosm units containing L. perenne plants. Both patches decomposed rapidly as shown by the amounts of 13C, as 13CO 2, released into the soil atmosphere, which peaked after 8 h for the earthworm patches and 48 h for the grass patches. In the decomposing grass patches the amounts of 13C and 15N remained co-varied and declined with time. No 13C added in the earthworm patches was detected in the soils, even after 3 days, confirming that decomposition of these patches was rapid. Grass patches supported greater microfaunal (nematode and protozoan) biomass than the earthworm patches, and microfaunal biomass peaked at day 7 on both. Plant N capture from both patches increased with dry weight increment although N capture from the earthworm patch was greater than that from the grass patch. By day 30 plants had captured 29% (from earthworms) and 22% (from grass) of the N originally available in the patches. No 13C enrichments from the patches were detected in the plant tissues indicating that organic compounds were not being taken up by the plant roots. As plants only took up inorganic N from the patch, our results indicate that microbes initially out-compete plants for the added N, but with time, plants capture more of the N originally added as they represent a slower turnover pool.

Effects of Nitrogen Fertilizer Application and Solar radiation on the Growth Response of Sorghum Seedlings to Soil Moisture.

ソルガムを窒素施用量と土壌水分含量ならびに日射量と土壌水分含量を複合的に変えた育苗箱条件下で栽培し, 土壌水分に対するソルガムの初期生育反応に及ぼす窒素施用量と日射量の影響について調査した.ソルガムの生育に対して基本的に土壌水分含量は生長促進作用としての線形要因的性格と阻害作用としての逆数要因的性格とを併せ持つ両性要因として作用するが, 最適土壌水分含量未満の範囲においては土壌水分の過剰による生育抑制項を欠いた逆数式で対応できた.窒素施用量は低土壌水分条件下では両性要因として作用したが土壌水分含量の増大に伴って逆数要因的特性が不明確となった.これらの関係は, 1/〓W=A/(f-f0)+B(g+g0)/(f-f0)+C/[(f-f0)(g+g0)]+D/(g+g0)+Eで近似できた.ここで, 〓W, fおよびgはそれぞれ全乾物増加量, 土壌水分含量, 窒素施用量, f0とg0は非有効土壌水分含量の上限値と土壌および種子からの窒素持ち込み量, またA, B, C, DとEは係数である.日射量は生育量に対して線形要因として作用し, 土壌水分含量と日射量を変えた複合条件下におけるソルガムの生育量は, 1/〓W=A/(S-S0)+B/(f-f0)+C(f-f0)+Dで近似できた.ここで, SとS0は日射量と日補償点である.以上の結果は, 日射量と土壌水分含量の影響はそれぞれ単独効果の和として表せるのに対して, 窒素施用量と土壌水分含量の複合条件下では両要因の交互作用効果が無視できないことを示している。また, 蒸散効率に対する土壌水分含量, 窒素施用量および日射量の影響は大きくないと考えられた.

Influence of temporary covers on the growth of nursery tree seedlings

SummarySeeds of Fagus sylvatica, Prunus avium and Acer pseudoplatanus were sown on 10 May and covered with four materials: white polyethylene, white polypropylene, yellow net or green net for 90 d to study the effect of a temporary covering on soil and air temperature, increment in dry weight, and root cellular diameter of nursery tree seedlings in a northern climate. Root collar diameter, height and dry weight of covered seedlings were compared with those of uncovered control seedlings at the end of growing season. The increase in soil and air temperature under white polyethylene, white polypropylene and yellow net and the decrease in soil temperature under the green net influenced the growth of F. sylvatica and P. avium seedlings. Dry weight, as well as root collar diameter and height, was increased under the coverings increasing temperature. A. pseudoplatanus responded less to temperature, but increased dry weight and root collar diameter when cultivated under white polypropylene and green net. Hence temporary coverings can be used to improve the quality of seedlings grown in a northern climate.

The Effect of Shading on the Growth of Young 'Fuji' Apple Trees.

Young apple trees were grown for two growing seasons under 100, 52.9, 34.2, 15.8 or 5.0% natural photosynthetic photon flux density (PPED) to assess the difference of growth on dry weight basis. Total dry weight gains of trees decreased with increasing shade, except for trees grown at 5.0% PPFD which showed a net loss at the end of the second growing season ; because dry weight of the root stem, and trunk decreased. Although the growth increment in the root system was negative at 5.0% PPFD, new roots were produced in small amounts in both seasons. Shading neither decreased the photosynthetic light compensation points of leaves nor increased the initial slopes of the light response curves. Specific leaf weight declined significantly with the decrease in light level to 5.0% PPFD. In trees receiving a PPFD level above 15.8%, 42.1 to 49.5% of the total increment of dry weight was partitioned to the old trunk and branches, respectively. A high correlation between total increment and trunk thickness (r=0.983**) was found, but not in trees under 5.0% PPFD. Therefore, the minimum light condition required to sustain a growth in dry weight increment in succeeding years appeared to be between 5.0 to 15.8% of natural sunlight in the northern part of Japan.

Differentiating Day from Night Effects of High Ambient [CO2] on the Gas Exchange and Growth ofXanthium strumariumL. Exposed to Salinity Stress

Sodium chloride, at a concentration of 88 mol m−3in half strength Hoagland nutrient solution, increased dry weight per unit area ofXanthium strumariumL. leaves by 19%, and chlorophyll by 45% compared to plants grown without added NaCl at ambient (350 μmol mol−1) CO2concentration. Photosynthesis, per unit leaf area, was almost unaffected. Even so, over a 4-week period, growth (dry weight increment) was reduced in the salt treatment by 50%. This could be ascribed to a large reduction in leaf area (>60%) and to an approx. 20% increase in the rate of dark respiration (Rd). Raising ambient [CO2] from zero to 2000 μmol mol−1decreased Rd in both control and salinized plants (by 20% at 1000, and by 50% at 2000 μmol mol−1CO2concentration) compared to Rd in the absence of ambient CO2. High night-time [CO2] had no significant effect on growth of non-salinized plants, irrespective of day-time ambient [CO2]. Growth reduction caused by salt was reduced from 51% in plants grown in 350 μmol mol−1throughout the day, to 31% in those grown continuously in 900 μmol mol−1[CO2]. The effect of [CO2] at night on salinized plants depended on the daytime CO2concentration. Under 350 μmol mol−1day-time [CO2], 900 μmol mol−1at night reduced growth over a 4-week period by 9% (P<0.05) and 1700 μmol mol−1reduced it by 14% (P<0.01). However, under 900 μmol mol−1day-time [CO2], 900vs. 350 μmol mol−1[CO2] at night increased growth by 17% (P<0.01). It is concluded that there is both a functional and an otiose (functionless) component to Rd, which is increased by salt. Under conditions of low photosynthesis (such as here, in the low day-time [CO2] regime) the otiose component is small and high night-time [CO2] partly suppresses functional Rd, thereby reducing salt tolerance. In plants growing under conditions which stimulate photosynthesis (e.g. with increased daytime [CO2]), elevated [CO2] at night suppresses mainly the otiose component of respiration, thus increasing growth. Consequently, in regions of adequate water and sunlight, the predicted further elevation of the world atmospheric [CO2] may increase plant salinity tolerance.

Basal-shoot formation in young rose plants: Effects of bending practices and plant density

SummaryTo examine the relations between plant architecture and flower production, the effect of bending practices and plant densities on basal-shoot formation was studied in young rose plants. After bending the primary shoot, there was a greater probability for the outgrowth of the two most basal buds. These two buds are already present as secondary buds in the axils of the scales of the axillary bud when used as a cutting for propagation. This probability was even more apparent when bending was delayed. The source capacity of the primary shoot, mainly reflected in the leaf area index (LAI), was determined by date of bending. Delayed bending increased the development rate, diameter, weight and cross sectional area (CSA) of basal shoots per plant. Plant growth rate, expressed as dry-weight increment per day, was positively related with LAI (and thus light interception) during the early phase of basal-shoot formation, although a maximum in plant growth rate was reached when stems were bent 28 d after T0 (ti...

Effect of Time and Rate of Nitrogen Application on Root Growth with Special Reference to Chinese F1-hibrid Rice "Shanyou 63".

The effect of time and rate of nitrogen application on root growth and their relations with constituents of top per hill were investigated using Chinese F1 hybrid rice (cv. Shanyou 63) under water culture conditions. Treatments of several nitrogen rates were applied in three growth stages : early growth stage (before 14.5 Plant age in leaf number), middle growth stage (13.5 to 17.0 plant age in leaf number), and late growth stage (17.0 plant age in leaf number to maturity). The number of crown root primordia and emerged crown roots, root dry weight, and some constituents of top per hill were investigated. In the early growth stage, root dry weight per hill increased as nitrogen concentration increased, and correlated rather with the root number than with the mean dry weight of root axis. In the middle growth stage, root dry weight per hill decreased with the increment of the nitrogen rate, especially in the roots of the upper three nodes. In the late growth stage, root growth was largely affected by nitrogen application during the middle growth stage, while little effect of the nitrogen rate was observed in root dry weight. The increment of root dry weight per hill in the middle growth stage was the largest followed by that of the early growth stage, and only a slight increment was observed in the late growth stage. High positive correlations were observed between the number of crown root primordia and the concentration of nitrogen of the top per hill at the crown root primordia differentiation time, and between the emergence rate of the crown roots and the concentration of starch at the time of emergence. From these results, it is believed that nitrogen and carbohydrate are the factors that promote the differentiation of crown root primordia and the emergence of crown roots, respectively.

Remobilization of iron from primary leaves of bean plants grown at various iron levels

Abstract In order to study the effect of different growth rates of the shoot apex, i.e. shoot demand, on the remobilization of iron (Fe) from mature (primary) leaves, bean (Phaseolus vulgaris L.) plants were precultured with 8x10‐5 M FeEDTA for four days. Thereafter, plants were grown for another six days at various levels of Fe (0.0, 1.0, and 10.0μM FeEDTA), and simultaneously treated with or without shading of one primary leaf. Dry weight increment of the shoot apex decreased with decreased Fe in the nutrient solution. Shading of one primary leaf decreased total dry weight of plants irrespective of Fe supply, but increased the dry weight of the shoot apex of plants supplied without Fe or with only 1.0μM Fe. In these plants, the concentration of chlorophyll and Fe in the shoot apex corresponded with the treatment effects on dry weight of the shoot apex. Shading induced senescence of the shaded leaf, decreased the content of “active Fe”; (extractable in dilute acid), and also enhanced the remobilization o...

Effects of nitrogen availability on northern red oak seedling growth in oak and pine stands in northern Lower Michigan

The nitrogen (N) status and dry weight increment of northern red oak (Quercusrubra L.) seedlings in relation to N availability were examined at various levels of canopy cover and understory removal treatments under field conditions in red oak and red pine (Pinusresinosa Ait.) stands. Net N mineralization rates over two growing seasons following canopy cover treatments were determined by the in situ buried bag technique. Canopy removal increased N mineralization in both oak and pine stands. Net N mineralization rates were ≈1.2–2.2 times higher in the clearcut and the other partial canopy cover treatments than in the uncut stands. Net N mineralization in the same canopy cover treatments was ≈2–3 times higher in red oak stands than in red pine stands. However, red oak seedlings from the same canopy cover treatments in both stand types had similar dry weight, N concentrations, N content, and N-use efficiency despite differences in soil N availability. The only exception was ≈2 times greater seedling dry weight and N content in the red oak clearcuts compared with the red pine clearcuts. The similarity in seedling performance within partial canopy removal or uncut stands may have been due to limiting factors other than N in the red oak stands. Red oak seedlings from litter removal treatments within the clearcuts had significantly higher N-use efficiency than those from the herb and shrub removal treatments. These results suggest that (i) canopy manipulation increases soil N availability; (ii) increases in dry weight and N uptake by red oak seedlings when forest canopies are completely removed are due, in part, to increased available soil N; (iii) red oak seedling response to soil N availability resulting from no or only partial canopy removal may be the same in different stand types (e.g., red oak vs. red pine) because factors other than N, such as light, are limiting.

Physiological, morphological and anatomical responses of Fraxinus mandshurica seedlings to flooding.

Two-year-old Fraxinus mandshurica Rupr. var. japonica Maxim. seedlings were flooded to 8 cm above soil level for 70 days. The flooding treatment altered the growth, morphology, stem anatomy and ethylene production of the seedlings. Although flooding did not affect height growth, it stimulated diameter growth of the submerged stems by increasing both the number and size of wood fibers produced; however, the thickness of the cell walls of the wood fibers was reduced by flooding. In response to the flooding treatment, the seedlings formed abundant hyperhydric tissues, originating from the vicinity of lenticels on the surface of the flooded stems, and adventitious roots, which grew through the hyperhydric tissues. Aerenchyma tissues were observed in the bark of the adventitious roots. The flooding treatment did not affect dry weight increment of leaves and stems, but it reduced the total dry weight increment of the root system even though it promoted adventitious root formation. Flooding also enhanced ethylene production in the submerged portions of stems. The potential roles of flood-induced ethylene in cambial growth and adventitious root formation in flooded plants are discussed.

Factors limiting the growth of indigenous tree seedlings planted on degraded rainforest soils in Sabah, Malaysia

During selective logging of tropical rainforest in Malaysia, the topsoil is removed from log landings and skid trails by bulldozers. The exposed subsoil is compacted, nutrient-poor, low in organic matter, drought-prone and hot. Vegetation on log landings and skid trails recovers extremely slowly. Tree seedlings planted on these degraded areas perform much less well than those planted in adjacent manually disturbed areas. An experiment was set up to investigate whether soil factors reduced early tree growth. The treatments used were: digging to reduce soil compaction; fertilizing to replace lost nutrients; mulching to reduce soil temperatures and evaporation rates; replacement of topsoil. Two pioneer tree species ( Macaranga hypoleuca and M. gigantea) and two dipterocarp species ( Dryobalanops lanceolata and Shorea leprosula) were planted in treated plots. Fertilizing of seedlings resulted in a dramatic improvement in height, basal diameter and dry weight increments of all species 6 months after planting. Digging improved seedling growth slightly, but mulching had little effect. This suggests that nutrient deficiency is the most important factor limiting early tree growth on degraded soil. Topsoil replacement resulted in growth as good as that of fertilized seedlings. The topsoil plots also contained 35 times more volunteer plants than any other treatment. Pioneer tree seedlings grew significantly faster than dipterocarp seedlings.

Growth, Morphology, Stem Anatomy, and Ethylene Production in Flooded Alnus Japonica Seedlings

Flooding of soil of potted, 24-month-old Alnus japonica seedlings for 24 days altered growth, morphology, stem anatomy, and ethylene production. This species exhibited high adaptability to soil flooding by forming adventitious roots that grew through hypertrophied lenticels. Aerenchyma tissues were observed in the bark of the adventitious roots. Flooding slightly reduced height growth and greatly stimulated diameter growth of submerged portions of stems in comparison with unflooded seedlings. Diameter growth in flooded seedlings was largely due to increases in both the number and size of wood fibres produeed during the flooding period. Flooding did not affect biomass increment of leaves and stems but reduced the total dry weight increment of the root system even though abundant adventitious roots had formed. Ethylene production in the submerged portions of stems was greatly increased by flooding. Morphological and anatomical responses of Alnus japonica seedlings to flooding are discussed.

Measuring Coconut Palm Dry Matter Production

Non-destructive methods are described for estimating annual above-ground dry matter production by the coconut palm, Cocos nucifera. Leaf dry weight is estimated from the cross-sectional area of the petiole. Trunk dry weight increment is estimated from the volume increment, and a function relating trunk density to palm age. Husk and shell dry weights are estimated from air-dry weights; copra dry weight is measured after oven drying. The weight of inflorescence stalks is small, and is ignored. Leaf area can be estimated from measurement of the length and width of a sample of leaflets. These methods have been applied to two coconut variety trials, and show significant differences between varieties in crop growth rate and harvest index. The trend of leaf area with palm age is described for two varieties and the hybrid between them.Medida de la producción de materia seca en el cocotero

Response of young barley plants to CO2enrichment

Barley (Hordeum vulgare L. cv. Digger) was grown for 22 d in enclosed chambers with a C02 enrichment of 35, 155, 400 or 675/?mol C02 mol'1. C02 enrichment increased photosynthetic capacity in the plants grown at either of the two highest levels of pC02. A C02 enrichment of 675 //mol C02 caused a significant increment of shoot dry weight, whereas no changes were observed in fresh weight, chlorophyll or protein levels. At a light intensity of 860//mol m'2s~1 C02 enrichment caused photosynthetic capacity to increase by 250%, whereas no effect was observed at 80 //mol m~2 s~1. Over time, photosynthesis decreased by 70% independent of C02. A time-dependent increase in the level of extractable fructose was observed whereas total extractable carbohydrate only changed slightly.

Effect of Temperature on the Size of Strawberry Fruit.

Strawberry, Fragaria × ananassa Duch. cv. Toyonoka, plants were grown from October onward in two glasshouses where the air temperature was controlled at either 15°or 19 °C night and day. Several days after pollination, the diameter of all the fruits in the first inflorescence (truss) was measured at approximately two-day intervals, and fully red ripe fruits were sampled. The growth of the fruits showed a double sigmoidal curve in all ranks of the inflorescence at both temperatures. The growth was faster in the higher rank fruits that developed earlier and at 19 °C than in the lower rank fruits and at 15 °C. Fresh and dry weight per fruit was larger in the higher rank fruits and at 15 °C (mean of all fruits; 0.879 g DW) than in the lower rank fruits and at 19 °C (mean of all fruits; 0.774 g DW). The total numbers of ripe fruits per inflorescence (plant) were slightly smaller at 19 °C. The values of the total fruit fresh and dry weight per inflorescence (plant) were much lower at 19 °C. The bearing fruit period from the flowering of the first flower to the ripening of the last fruit in the inflorescence was 88 days at 15 °C and 69 days at 19 °C, respectively. The daily dry weight increments of total fruit in the inflorescence (per plant) were 0.170 g at 15 °C and 0.151 g at 19 °C. It was considered that the small size of the fruits at a high temperature like 19 °C was not caused by the increase in the number of fruits. but by the low rate of dry matter accumulation in fruit.

Modeling mepiquat chloride-temperature interactions in cotton: the model

The plant growth regulator mepiquat chloride (1,1-dimethylpiperidinium chloride) is used to reduce vegetative growth in cotton. It is commonly used to control the side effects of optimization of inputs such as water and nitrogen. It has been shown that mepiquat chloride (MC) suppresses excessive plant growth by decreasing plant height, number of nodes, fruiting and vegetative branch lengths, and leaf area. A model was developed using data collected under controlled environmental conditions for a range of temperatures. Equations were developed to calculate the concentration of MC in the plant tissue on a daily basis after accounting for the dry-weight increments in plant tissue and abscission of plant parts. A set of stress factors was calculated to account for the reduction in growth of various cotton plant parts as a function of air temperature and tissue concentration of MC. The MC model was incorporated in a cotton simulation model, GOSSYM. The model simulations compared well with observed yields under a range of conditions.

Preliminary assessment of a microencapsulated diet for larval culture of the Sydney rock oyster, Saccostrea commercialis (Iredale & Roughley)

A microencapsulated artificial diet was assessed against a standard diet of micro algae in rearing larvae of the Sydney rock oyster, Saccostrea commercialis (Iredale & Roughley). Unfed control larvae did not develop beyond the straight-hinge stage during the 8-day experiment, whereas those receiving exogenous nutrients, either microalgae or the artificial diet, reached umbone stage. The artificial diet supported larval growth in excess of 80% that of algae-fed larvae in terms of shell length increment; however, there was no significant difference in ash-free dry weight increment between larvae fed the artificial diet and those fed microalgae. Dissolved yeast extract did not enhance larval growth when used as a supplement to the microcapsules. The relative growth rates obtained are the best to date for oyster larvae reared on an artificial diet. The artificial diet used will serve as a benchmark for future nutritional studies with S. commercialis larvae, allowing further development of artificial diets for this species.

Yield improvement of oilseed rape (Brassica napus L.) in a low rainfall environment. II. Agronomic performance of lines selected on the basis of pre-anthesis development

Agronomic characteristics of two groups of early flowering Brassica napus lines and their respective parents were compared at East Beverley in the Western Australian wheatbelt. These lines had been derived through two generations of backcrossing and subsequent selfing from crosses of the B. napus cultivar Wesbrook (recurrent parent) with an early flowering B. napus line RU2 and an even earlier flowering B. campestris population Chinoli C42. Lines selected for this experiment had flowered earliest in a previous controlled environment experiment. Only RU2 and one WesbrookxRU2 line (IB72) had significantly higher yields than Wesbrook (149% and 166% respectively), and one Wesbrookxchinoli C42 line was the only line to have a significantly lower yield than Wesbrook. None of the lines had significantly higher yields than their respective non-recurrent parents. Although RU2 and IB72 flowered much earlier than Wesbrook, there was no significant relationship between flowering time and seed yield over all lines. Lines which were the earliest to commence stem elongation tended to have higher seed yields. However, of all the growth and development characters measured, the biological yield and the dry weight increment between commencement of flowering and maturity were most closely related to seed yield. RU2 and IB72 accumulated far more dry matter over the post-anthesis period than Wesbrook and all other lines except another WesbrookxRU2 line. The superior post-anthesis growth of RU2 and IB72 may simply be a manifestation of the longer period available for growth under more favourable environmental conditions or deeper roots extracting more water from a greater depth. However, since there was no relationship between flowering time and the post-anthesis dry matter increment, it seems more likely that IB72 has received genes for superior post-anthesis growth as well as those determining early flowering from RU2. Given the rapid decline in soil moisture availability during post-anthesis development in this environment, these genes may affect post-anthesis growth through determining a greater capacity for drought avoidance. The implications of these results are discussed with particular reference to the breeding of higher yielding B. napus cultivars for lower rainfall environments.