Ecological growth response specificity of two Douglas-fir ecotypes inoculated with coexistent beneficial rhizosphere bacteria

1994 ◽  
Vol 72 (5) ◽  
pp. 582-586 ◽  
Author(s):  
C. P. Chanway ◽  
F. B. Holl
Keyword(s):  
Seedling Growth ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Douglas Fir ◽  
Rhizosphere Bacteria ◽  
Pseudomonas Aureofaciens ◽  
Root Dry Weight ◽  
Arthrobacter Oxydans ◽  
Significant Stimulatory Effect ◽  
Effect On Growth

The influence of inoculation with rhizosphere bacteria on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedling emergence in a controlled environment and on survival and growth in the field was investigated. Seed or seedlings of interior and coastal Douglas-fir ecotypes originating from the vicinity of Williams Lake and Chilliwack, British Columbia, Canada, respectively, were inoculated with two strains of rhizosphere bacteria, Arthrobacter oxydans strain N74 and Pseudomonas aureofaciens strain K23. These strains were previously isolated from naturally regenerating Douglas-fir seedlings collected from the Williams Lake and Chilliwack sites, respectively. Seed inoculation with either strain of bacteria, K23 or N74, stimulated the rate of seedling emergence, but these effects were not ecotype specific. While inoculation did not affect germination percentage, ecotype-specific seedling growth responses were detected 13 months after field planting. Arthrobacter oxydans strain N74 significantly stimulated seedling branching and enhanced root and shoot dry weight of the Williams Lake ecotype but had no significant stimulatory effect on growth of the Chilliwack ecotype. Pseudomonas aureofaciens strain K23 significantly stimulated shoot branching and root dry weight of Chilliwack Douglas-fir but had no significant stimulatory effect on growth of that from Williams Lake. When treatments of Douglas-fir seedlings and rhizosphere bacteria that originated from the same geographic site were pooled and compared with uninoculated controls, significant increases in shoot branch number and root dry weight were also detected. No significant difference in seedling growth was detected when treatments of seedlings and bacteria that originated from different sites were pooled and compared with uninoculated controls. Based on these results, we hypothesize that plant–microbe specificity may be an important component of Douglas-fir – beneficial rhizosphere bacteria interactions in the field. Key words: Douglas-fir seedlings, emergence, growth, rhizosphere bacteria, inoculation.

Genetic variation for rate of establishment in caucasian clover

1998 ◽  
pp. 213-217
Author(s):  
K.H. Widdup ◽  
T.L. Knight ◽  
C.J. Waters
Keyword(s):  
Genetic Variation ◽  
Root Growth ◽  
Seedling Growth ◽  
White Clover ◽  
Seedling Emergence ◽  
Red Clover ◽  
Dry Weight ◽  
Cool Season ◽  
Trifolium Ambiguum ◽  
Root Dry Weight

Slow establishment of caucasian clover (Trifolium ambiguum L.) is hindering the use of this legume in pasture mixtures. Improved genetic material is one strategy of correcting the problem. Newly harvested seed of hexaploid caucasian clover germplasm covering a range of origins, together with white and red clover and lucerne, were sown in 1 m rows in a Wakanui soil at Lincoln in November 1995. After 21 days, the caucasian clover material as a group had similar numbers of emerged seedlings as white clover and lucerne, but was inferior to red clover. There was wide variation among caucasian clover lines (48-70% seedling emergence), with the cool-season selection from cv. Monaro ranked the highest. Recurrent selection at low temperatures could be used to select material with improved rates of seedling emergence. Red clover and lucerne seedlings produced significantly greater shoot and root dry weight than caucasian and white clover seedlings. Initially, caucasian clover seedlings partitioned 1:1 shoot to root dry weight compared with 3:1 for white clover. After 2 months, caucasian clover seedlings had similar shoot growth but 3 times the root growth of white clover. Between 2 and 5 months, caucasian clover partitioned more to root and rhizome growth, resulting in a 0.3:1 shoot:root ratio compared with 2:1 for white clover. Both clover species had similar total dry weight after 5 months. Unhindered root/ rhizome devel-opment is very important to hasten the establishment phase of caucasian clover. The caucasian clover lines KZ3 and cool-season, both selections from Monaro, developed seedlings with greater shoot and root growth than cv. Monaro. KZ3 continued to produce greater root growth after 5 months, indicating the genetic potential for improvement in seedling growth rate. Different pasture estab-lishment techniques are proposed that take account of the seedling growth characteristics of caucasian clover. Keywords: establishment, genetic variation, growth, seedling emergence, Trifolium ambiguum

EMERGENCE AND SEEDLING GROWTH OF INBRED LINES OF CORN AT SUBOPTIMAL ROOT-ZONE TEMPERATURES

1987 ◽  
Vol 67 (2) ◽  
pp. 409-415 ◽  
Author(s):  
A. MENKIR ◽  
E. N. LARTER
Keyword(s):  
Zea Mays ◽  
Seedling Growth ◽  
Root Zone ◽  
Seedling Emergence ◽  
Correlation Coefficients ◽  
Dry Weight ◽  
Inbred Lines ◽  
Root Zone Temperature ◽  
Emergence Percentage ◽  
Zone Temperature

Based on the results of an earlier paper, 12 inbred lines of corn (Zea mays L.) were evaluated for emergence and seedling growth at three controlled root-zone temperatures (10, 14, and 18 °C). Low root-zone temperatures, 10 and 14 °C, were detrimental to emergence, seedling growth, and root growth of all inbred lines. Differential responses of inbred lines were observed within each temperature regime. The differences in seedling emergence among lines became smaller with increasing root-zone temperature, while the reverse was true for seedling dry weight. Simple correlation coefficients showed a significantly (P = 0.05) negative association between emergence percentage and emergence index (rate). Neither of these two emergence traits was significantly correlated with seedling dry weights. Seedling dry weights were significantly (P = 0.01) and positively associated with root dry weights. Two inbred lines exhibited good tolerance to low root-zone temperatures, viz. CO255 and RB214. A significant and positive correlation existed between emergence percentage at a root-zone temperature of 10 °C and field emergence in test with the same genotypes reported earlier. Selection at a root-zone temperature of 10 °C for a high percentage of seedling emergence, therefore, could be effective in identifying genotypes capable of germinating in cool soils. Furthermore, the significantly (P = 0.01) positive relationship between seedling dry weights at all root-zone temperatures and those from the field test suggest that strains with vigorous seedling growth in the field could be identified using low root-zone temperature regimes.Key words: Zea mays, root-zone temperature, cold tolerance

scholarly journals Exogenous Antioxidants Enhance Seedling Growth and Yield of Artificially Aged Cabbage and Lettuce Seeds

Horticulturae ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 274
Author(s):  
Ademola Adetunji ◽  
Sershen ◽  
Boby Varghese ◽  
Norman Pammenter
Keyword(s):  
Leaf Area ◽  
Seedling Growth ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Growth And Yield ◽  
Seed Vigour ◽  
Beneficial Effects ◽  
Shoot Dry Weight ◽  
Antioxidant Defence System ◽  
Aged Seeds

Aged seeds exhibit compromised vigour in terms of germination, seedling emergence and growth, but this can to some extent be alleviated by invigoration treatments before sowing. This study aimed to investigate ageing rates and patterns in cabbage (Brassica oleraceae) and lettuce (Lactuca sativa) seeds and whether the beneficial effects of invigorating aged seeds with exogenous antioxidants translate to enhanced seedling performance. Seeds were artificially aged to 25% viability before soaking in 0.4 mM glycerol, 0.6 mM GSH and 0.2 mM trolox for cabbage, and 0.6 mM glycerol, GSH and trolox for lettuce; deionised water served as a control. After 14 days of sowing, seedling emergence percentage, mean emergence time, mean daily emergence, and time taken to 25% emergence were computed. Seedling vigour index, root and shoot dry weight, root:shoot ratio, leaf area, leaf area ratio, and leaf chlorophyll content were assessed 6 weeks after sowing. Furthermore, the photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), and chlorophyll fluorescence were measured 6 weeks after sowing. Notably, ageing resulted in the loss of seed vigour and viability at higher rates in lettuce than cabbage. Seed pretreatment with glycerol promoted seedling growth in both species and shoot dry weight in lettuce, while glycerol and GSH enhanced Pn, Gs and E in lettuce. Trolox also enhanced Pn and E in lettuce. The beneficial effects of the antioxidant treatments are thought to be associated with the protection of photosystems from oxidative stress and/or stimulation of enzymes involved in photosynthesis, possibly through an enhanced antioxidant defence system during the early development stages when seedlings are particularly vulnerable to stress.

Effect of forest floor on growth and nutrition of Douglas-fir and western hemlock seedlings with and without fertilizer

1992 ◽  
Vol 22 (9) ◽  
pp. 1222-1229 ◽  
Author(s):  
M.A. Radwan
Keyword(s):  
Seedling Growth ◽  
Forest Floor ◽  
Dry Weight ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Seed Sources ◽  
Shoot Dry Weight ◽  
Growth And Nutrition ◽  
Forest Floors ◽  
P Fertilizers

Experiments were conducted to determine the effects of four different forest soils on growth and shoot nutrients of potted Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings, in absence and in presence of forest floor, and with and without N and P fertilizers. Nine-month-old seedlings from low-elevation seed sources were used, and seedlings were grown for 2 years in a roofed lathhouse. Soils were of the Klone, Vesta, Bunker, and Shelton series; Klone and Vesta soils, and Bunker and Shelton soils, were collected from western hemlock and Douglas-fir stands, respectively. The fertilizers ammonium nitrate at 100 kg N/ha and triple superphosphate at 226 kg P/ha were tested. The forest floor, at 70 g/7.6-L pot, and the N and P fertilizers were added to the top of the planting pots without mixing. The forest floors and mineral soils differed by source in many of the chemical characteristics determined. Overall, seedling growth of Douglas-fir and western hemlock was better in the Klone and Shelton soils than in the Bunker and Vesta soils. Seedlings, especially those of western hemlock, grew better with than without forest floor. The N fertilizer reduced seedling growth of both species and, in some soils, reductions were more with than without forest floor. The P fertilizer improved seedling growth of both species in all soils and, with one exception, growth was much greater in the presence than in the absence of the forest floor. With both species, soil, forest-floor, and fertilization treatments affected concentrations and contents of the various shoot nutrients determined. The nutritional changes observed varied by nutrient and reflected differences in uptake of native and fertilizer nutrients, as well as changes in shoot dry weight. The results demonstrate the importance of the forest floor to growth and nutrition of Douglas-fir and western hemlock seedlings, especially when fertilizers are used.

scholarly journals Seedling Growth of Catawba Rhododendron. I. Temperature Optima, Leaf Area, and Dry Weight Distribution

HortScience ◽  
1994 ◽  
Vol 29 (11) ◽  
pp. 1298-1302 ◽  
Author(s):  
D. Bradley Rowe ◽  
Stuart L. Warren ◽  
Frank A. Blazich
Keyword(s):  
Leaf Area ◽  
Seedling Growth ◽  
Weight Ratio ◽  
Dry Weight ◽  
High Elevation ◽  
Root Weight ◽  
Root Dry Weight ◽  
Leaf Weight Ratio ◽  
Leaf Weight ◽  
Total Plant

Catawba rhododendron (Rhododendron catawbiense Michx.) seedlings of two provenances, Johnston County, N.C. (35°45′N, 78°12′W, elevation = 67 m), and Yancey County, N.C. (35°45′N, 82°16′W, elevation = 1954 m), were grown in controlled-environment chambers for 18 weeks with days at 18, 22, 26, or 30C in factorial combination with nights at 14, 18, 22, or 26C. Shoot and root dry weights and total leaf areas of seedlings of the Yancey County provenance (high elevation) exceeded (P ≤ 0.05) those of the Johnston County (low elevation) provenance at all temperature combinations. Leaf area was maximal at 22/22C, 18/26C, and 22/26C and minimal at 30/14C (day/night). Shoot dry weight responded similarly. Root dry weight decreased linearly with increasing day temperature, but showed a quadratic response to night temperature. Leaf weight ratio (leaf dry weight: total plant dry weight) increased, while root weight ratio (root dry weight: total plant dry weight) decreased with increasing day temperature. Leaf weight ratio was consistently higher than either stem or root weight ratios. Day/night cycles of 22 to 26/22C appear optimal for seedling growth.

scholarly journals Coir as an Alternative to Peat in Media for Tomato Transplant Production

HortScience ◽  
2002 ◽  
Vol 37 (2) ◽  
pp. 309-312 ◽  
Author(s):  
M. Arenas ◽  
C.S. Vavrina ◽  
J.A. Cornell ◽  
E.A. Hanlon ◽  
G.J. Hochmuth
Keyword(s):  
Leaf Area ◽  
Seedling Emergence ◽  
C:N Ratio ◽  
Dry Weight ◽  
Medium Composition ◽  
Stem Diameter ◽  
Tomato Seed ◽  
Root Dry Weight ◽  
Growth Differences ◽  
Summer Fruit

Sixteen media prepared from peat, coir, vermiculite, or perlite were used to determine the optimum growing media for tomato (Lycopersicum esculentum Mill.) transplants. Medium composition did not affect tomato seed emergence, although seedling emergence was higher in winter (90%) than summer (85%). Greatest transplant root dry weight, stem diameter, and leaf area were achieved in 50% to 75% peat + 25% to 50% vermiculite in summer. In winter, greatest transplant root dry weight, stem diameter, and leaf area were achieved in eight media: 100% peat, 75% peat + 25% vermiculite, 75% peat + 25% perlite, 50% peat + 50% vermiculite, 50% peat + 50% perlite, 25% peat + 50% coir + 25% vermiculite, 50% peat + 25%coir + 25% vermiculite, and 25% peat +25% coir +25% vermiculite +25% perlite. Transplants grown with >50% coir exhibited reduced plant growth compared to peat-grown transplants, a response that may be associated with high N immobilization by microorganisms and high C:N ratio. Despite transplant growth differences during the summer, fruit yields generally were unaffected by transplant media.

scholarly journals Container Volume and Height Affect Shoot and Root Development in Marigold Seedlings

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 868B-868
Author(s):  
Jennifer Marohnic ◽  
Robert L. Geneve
Keyword(s):  
Cell Volume ◽  
Leaf Area ◽  
Seedling Growth ◽  
Root Development ◽  
Dry Weight ◽  
Seedling Development ◽  
Root Number ◽  
Positive Correlation ◽  
Root Dry Weight ◽  
The Impact

Marigold seedlings were grown in four containers that differed in both volume and shape. Seedlings grown in 1.5-gal containers showed the greatest potential for shoot and root development 20 days after sowing. These seedlings had greater leaf area, shoot and root dry weight, and total root number and length compared to seedlings grown in 406 plug trays, 72-cell packs, or 6-inch containers. There was a positive correlation (r2 = 0.81) between cell volume and seedling growth as well as a positive correlation (r2 = 0.89) between container height with seedling growth. An attempt was made to separate the impact of container volume vs. container height on seedling growth. Containers were designed using acrylics to vary the container height while keeping the volume constant at 1500 cm3. There was a positive correlation (r2 = 0.87) between shoot and root dry weight with container height. The data suggest that both container volume and height contribute to overall seedling growth in marigold, but when container volume is not limiting, container height has a large impact on seedling development.

Use of the ectomycorrhizal fungus Laccarialaccata in forestry. I. Consistency between isolates in effective colonization of containerized conifer seedlings

1982 ◽  
Vol 12 (3) ◽  
pp. 469-473 ◽  
Author(s):  
Randy Molina
Keyword(s):  
Seedling Growth ◽  
Ponderosa Pine ◽  
Dry Weight ◽  
Sitka Spruce ◽  
Ectomycorrhizal Fungus ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Conifer Species ◽  
Colonization Success ◽  
Inoculation Treatment

Four isolates of the ectomycorrhizal fungus Laccarialaccata (Scop. ex Fr.) Berk and Br. were inoculated singly onto containerized Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), ponderosa pine (Pinusponderosa Dougl. ex Laws.), Sitka spruce (Piceasitchensis (Bong.) Carr.), and western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings to detect ecotypic variation in colonization success and effects on seedling growth. All isolates formed well-developed ectomycorrhizae on all inoculated seedlings. Abundance ratings of short roots colonized did not differ between the four isolates for any conifer species; most inoculated seedlings developed ectomycorrhizae on over 80% of their short roots. There were also no differences between isolates in affecting seedling height, stem diameter, and dry weight of tops and roots for all conifer species. Inoculations did not improve seedling growth over uninoculated controls. Uninoculated controls of Douglas-fir and ponderosa pine had significantly greater dry weight than their inoculated seedlings; growth of Sitka spruce and western hemlock seedlings was not affected by any inoculation treatment. Laccarialaccata vigorously colonized the entire container rooting substrate and appears a prime candidate for artificial ectomycorrhizal inoculation of containerized western conifers.

scholarly journals Seedling Growth of Wheat as Affected by Soil Salinity

2018 ◽  
Vol 20 (2) ◽  
pp. 53-66
Author(s):  
E Sultana ◽  
MA Hasan ◽  
S Sikder ◽  
MS Rana ◽  
F Alam
Keyword(s):  
Salt Tolerance ◽  
Seedling Growth ◽  
Soil Salinity ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Stress Sensitivity ◽  
Saline Stress ◽  
Tolerance Index ◽  
Wheat Genotypes ◽  
Salt Tolerance Index

An experiment was conducted to evaluate seedling growth of wheat under saline condition. Thirty wheat genotypes were grown in trays containing different levels of salinity (Control, 6 and 12 dSm-1) during October to December, 2013. Seedling emergence index, shoot and root length, shoot and root dry weight were found to be reduced with the increases of soil salinity level but the degree of reduction were not similar for all wheat genotypes. Salt tolerance index (STI) also indicated a wide difference in salt tolerance among the wheat genotypes. Sourav, Gourav, Shatabdi, BAW 1185, BAW 1186, BAW 1187, BAW 1189 and BAW 1193 were more salt tolerance while BAW 1177, BAW 1190 and BAW 1198 showed greater salt sensitivity than the other wheat genotypes at 6 dS m-1. However, at 12 dS m-1, Sourav, Gourav, Shatabdi, Sufi and BAW 1184 showed more salt tolerance and BAW 1183, BAW 1190, BAW 1192, BAW 1194 and BAW 97 provided greater stress sensitivity among the testing wheat genotypes. Considering both saline stress Sourav, Gourav and Shatabdi were found to be salt tolerant and BAW 1190 was saline sensitive wheat genotypes.Bangladesh Agron. J. 2017, 20(2): 53-66

Some effects of differing times of seedling emergence, population density and seed size on root-size variation in carrot populations

1982 ◽  
Vol 98 (3) ◽  
pp. 537-545 ◽  
Author(s):  
L. R. Benjamin
Keyword(s):  
Population Density ◽  
Seed Size ◽  
Plant Root ◽  
Seedling Emergence ◽  
Size Variation ◽  
Dry Weight ◽  
High Population ◽  
High Population Density ◽  
Root Dry Weight ◽  
Root Size

SUMMARYIn three experiments the effects of population density, spread in time of seedling emergence and variation in seed size on carrot plant-to-plant root-size variation were investigated.In the first experiment, coefficient of variation, c.v., of root dry weight was only 27–33% when using uniform growing conditions, graded seed, low population density and synchronous seedling emergence (i.e. over 3–11 days). Allowing asynchronous emergence (i.e. over 8–21 days) increased the c.v. to 32–37%, whereas increasing population density from 25 to 400 plants/m2, but maintaining synchronous seedling emergence, produced a c.v. of 57–73%. Asynchronous emergence combined with high population density increased the c.v. even further to 79–97%. Spread in time of emergence was associated with 5–48% of the plant-to-plant root-size variation. Thus asynchrony of seedling emergence was a source of plant-to-plant root-size variation and this effect was magnified by high population density, but other sources of variation were also important. Statistical analysis showed that the effects of these other sources of root-size variation were no greater in populations where emergence had occurred over only 3 or 4 days than in those where emergence had occurred over 3 weeks.There was no effect on root-size frequency distribution in a second experiment in which the spread of seedling emergence was truncated from 19 to 14 days by spraying paraquat onto the first seedlings to emerge from field plots.In a third experiment seeds 1·6–2·0 or 1·0–1·25 mm in diameter were grown in pure or mixed populations under conditions similar to those of the synchronous emergence high-density treatment of Expt 1. Storage roots derived from the large seeds weighed 38% more than those derived from the small seeds. Thus differences in seed size caused some of the root-size variation not already linked with different seedling emergence times. However, the c.v. of root dry weight from all the plants in mixed seed population was not greater than the c.v.s of root dry weight of either of the pure seed populations.

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