MORPHOLOGICAL DEVELOPMENT OF TWO ALFALFA CULTIVARS UNDER VARIOUS HARVESTING SCHEDULES

1974 ◽  
Vol 54 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Y. SINGH ◽  
J. E. WINCH
Keyword(s):  
Growth Rates ◽  
Dry Weight ◽  
Growing Season ◽  
Field Conditions ◽  
Morphological Development

Two alfalfa cultivars grown under field conditions were harvested at different stages of maturity during the growing season of 1969. The number of buds and stems that originated from various locations on the plant and the dry weight of the stems were recorded periodically. The pattern of regrowth was the same for both cultivars. During regrowth, following all stages of harvest, many buds that developed early failed to produce mature stems. Uncut alfalfa produced a second crop of regrowth stems from the bases of stems that formed the first growth. After each harvest regrowth stems originated mainly from the stubble of the most recently harvested stems. Yield reductions occurring in successive regrowths of each harvest schedule were due mainly to the production of smaller stems. Increased growth rates following more mature stages of cutting resulted mainly from faster elongation of stems developing from larger buds. The implications of these findings with respect to the breeding of alfalfa are discussed.

Biology of Fire Ephemerals of the Sandplains of the Kwongan of South-Western Australia

1985 ◽  
Vol 12 (6) ◽  
pp. 641 ◽  
Author(s):  
JS Pate ◽  
NE Casson ◽  
J Rullo ◽  
J Kuo
Keyword(s):  
Life Cycle ◽  
Reproductive Biology ◽  
Seedling Growth ◽  
Western Australia ◽  
Growth Rates ◽  
Dry Matter ◽  
Dry Weight ◽  
Growing Season ◽  
Adaptive Significance ◽  
Sexually Dimorphic

The growth, longevity, mineral relationships and reproductive biology of 18 species of fire ephemerals were examined in sclerophyllous shrubland, located mainly within the Jurien : Badgingarra region of the Northern Sandplains of the kwongan of SW. Australia. Ten of the species were monocarpic, completing their life cycle within the 6-8 month winter growing season after a summer or autumn fire. The remaining species were polycarpic, commencing reproduction in their second season and surviving and reproducing for a further two to eight seasons (depending on species). Detailed study was made of growth and dry matter allocation in the dioecious, sexually dimorphic, polycarpic species Tersonia brevipes (Gyrostemonaceae). Monocarpic species tended to produce smaller seeds, and exhibited greater seed output per unit biomass and higher harvest indices for dry matter and minerals than polycarpic species. Certain monocarpic species showed great plasticity in final dry weight, e.g. a 2700-fold difference between largest and smallest individuals in a sample of 250 plants of Stipa elegantissima (Poaceae), and a 180-fold range in a similarly sized sample of Macarthuria apetala (Aizoaceae). The fire ephemerals studied generally exhibited faster seedling growth rates, greater concentrations of P and N (but not of Ca, Mg and K) in seedling dry matter, but usually lesser concentrations of P and N (but not of Ca, Mg and K) in seed dry matter than in cohabiting obligate seeder or sprouter species with potential life spans exceeding 15 years. The above-mentioned features of fire ephemerals are suggested to be of special adaptive significance within the context of exploitation of transiently non-limiting habitat resources immediately following fire.

Density-dependent growth in cockles (Cerastoderma edule): evidence from interannual comparisons

1993 ◽  
Vol 73 (2) ◽  
pp. 333-342 ◽  
Author(s):  
K. Thomas Jensen
Keyword(s):  
Growth Rates ◽  
Dry Weight ◽  
Growing Season ◽  
Intertidal Mudflat ◽  
Low Density ◽  
Cerastoderma Edule ◽  
Density Dependent ◽  
The Difference ◽  
Dependent Growth ◽  
Growth Differences

To examine density-dependent effects on growth in Cerastoderma edule (L.) (Bivalvia), growth rates of individual cockles established by chance at high and low densities on the same intertidal mudflat in two different years (1984 and 1989) were compared. Two-year-old cockles occurring at high densities (>2000 individuals m-2 in 1984) attained mean lengths from 16.1 to 18.8 mm on the lower shore at the end of their third growing season, while low-density cockles (<50 individuals m-2 in 1989) of the same age reached mean lengths in the range of26.5 to 30.3mm. In terms of individual weight the difference between cockles from the two periods was even more striking, as the flesh ash-free dry-weight of a cockle from 1984 constituted only 7% of that from a 1989 cockle. During both periods growth in cockles increased with the duration of tidal submersion, but the interannual growth differences exceeded by far the effect of differences in submersion time.

Interior spruce seedlings compared with emblings produced from somatic embryogenesis. I. Nursery development, fall acclimation, and over-winter storage

1994 ◽  
Vol 24 (7) ◽  
pp. 1376-1384 ◽  
Author(s):  
S.C. Grossnickle ◽  
J.E. Major ◽  
R.S. Folk
Keyword(s):  
Somatic Embryogenesis ◽  
Root Growth ◽  
Freezing Tolerance ◽  
Growth Rates ◽  
Frozen Storage ◽  
Dry Weight ◽  
Growing Season ◽  
First Year ◽  
Terminal Bud ◽  
Interior Spruce

Interior spruce (Piceaglauca (Moench) Voss × Piceaengelmannii Parry) seedlings and emblings (plants produced via somatic embryogenesis tissue culture) were grown as container 1 + 0 plants. Seedling and embling morphological development was monitored during the growing season. Needle freezing tolerance, days to terminal bud break (DBB1), root growth capacity (RGC), and shoot dry weight fraction (DWF) were monitored during the fall and in frozen storage. Emblings had slower height, diameter, and root growth rates during the initial 2.5 months in the nursery. Thereafter, seedlings and emblings had equal height growth rate, while emblings had greater diameter and root growth rates. At the end of the growing season, seedlings and emblings, respectively, had 23.8 and 14.2 cm shoot height, 4.0 and 3.4 mm diameter, and 0.81 and 0.80 g root dry weight. During the fall, DBB1 of both seedlings and emblings decreased, with emblings having a more rapid decrease. Both seedlings and emblings showed a similar increase in freezing tolerance. Emblings had a greater increase in DWF. During the fall, RGC decreased then increased, with seedlings displaying a greater increase than emblings. While in frozen storage, seedlings and emblings maintained a low DBB1, and a high RGC and DWF. Freezing tolerance decreased while in frozen storage, with the loss more pronounced among seedlings. A degree growth stage model describes the first year cycle of development for seedlings and emblings. Results indicate that seedlings and emblings have slightly different patterns of first year growth and fall acclimation. However, both seedlings and emblings were at the end of rest when lifted for frozen storage.

scholarly journals Application of Bio-Friendly Formulations of Chitinase-Producing Streptomyces cellulosae Actino 48 for Controlling Peanut Soil-Borne Diseases Caused by Sclerotium rolfsii

2021 ◽  
Vol 7 (3) ◽  
pp. 167
Author(s):  
Gaber Abo-Zaid ◽  
Ahmed Abdelkhalek ◽  
Saleh Matar ◽  
Mai Darwish ◽  
Muhammad Abdel-Gayed
Keyword(s):  
Open Field ◽  
Biocontrol Agent ◽  
Sclerotium Rolfsii ◽  
Dry Weight ◽  
Culture Broth ◽  
Field Conditions ◽  
Damping Off ◽  
Mycelium Growth ◽  
Particle Size Analyzer ◽  
Cell Pellet

Of ten actinobacterial isolates, Streptomyces cellulosae Actino 48 exhibited the strongest suppression of Sclerotium rolfsii mycelium growth and the highest chitinase enzyme production (49.2 U L−1 min−1). The interaction between Actino 48 and S. rolfsii was studied by scanning electron microscope (SEM), which revealed many abnormalities, malformations, and injuries of the hypha, with large loss of S. rolfsii mycelia density and mass. Three talc-based formulations with culture broth, cell-free supernatant, and cell pellet suspension of chitinase-producing Actino 48 were characterized using SEM, Fourier transform infrared spectroscopy (FTIR), and a particle size analyzer. All formulations were evaluated as biocontrol agents for reducing damping-off, root rot, and pods rot diseases of peanut caused by S. rolfsii under greenhouse and open-field conditions. The talc-based culture broth formulation was the most effective soil treatment, which decreased the percentage of peanut diseases under greenhouse and open-field conditions during two successive seasons. The culture broth formulation showed the highest increase in the dry weight of peanut shoots, root systems, and yielded pods. The transcriptional levels of three defense-related genes (PR-1, PR-3, and POD) were elevated in the culture broth formulation treatment compared with other formulations. Subsequently, the bio-friendly talc-based culture broth formulation of chitinase-producing Actino 48 could potentially be used as a biocontrol agent for controlling peanut soil-borne diseases caused by S. rolfsii.

Seed morphology and ultrastructure in Citrus garrawayi (Rutaceae) in relation to germinability

2007 ◽  
Vol 55 (6) ◽  
pp. 618 ◽  
Author(s):  
Kim N. Hamilton ◽  
Sarah E. Ashmore ◽  
Rod A. Drew ◽  
Hugh W. Pritchard
Keyword(s):  
Moisture Content ◽  
Seed Size ◽  
Seed Coat ◽  
Outer Integument ◽  
Dry Weight ◽  
Seed Morphology ◽  
Embryonic Axis ◽  
Morphological Development ◽  
Seed Moisture Content ◽  
Immature Seeds

Combinational traits of seed size and seed-coat hardness in Citrus garrawayi (F.M.Bailey) (syn. of Microcitrus garrowayi) were investigated as markers for estimation of seed morphological and physiological maturity. Seed size (length) and coat hardness correlated well with changes in seed coat and embryo morphological development, dry-weight accumulation, decreases in moisture content and a significant increase in germinability. Seed moisture content decreased from 82 ± 1% in immature seeds to 40 ± 1% at seed maturation. The outer integument of immature seeds consisted of thin-walled epidermal fibres from which outgrowths of emerging protrusions were observed. In comparison, mature seed coats were characterised by the thickening of the cell walls of the epidermal fibres from which arose numerous protrusions covered by an extensive mucilage layer. Immature seeds, with incomplete embryo and seed-coat histodiffereniation, had a low mean germination percentage of 4 ± 4%. Premature seeds, with a differentiated embryonic axis, were capable of much higher levels of germination (51 ± 10%) before the attainment of mass maturity. Mature seeds, with the most well differentiated embryonic axis and maximum mean dry weight, had the significantly highest level of germination (88 ± 3%).

Reassessment of Maximum Growth Rates for C3 and C4 Crops

1978 ◽  
Vol 14 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. L. Monteith
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growing Season ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Crop Growth ◽  
Close Inspection ◽  
Similar Difference ◽  
Photosynthetic Efficiencies

SUMMARYFigures for maximum crop growth rates, reviewed by Gifford (1974), suggest that the productivity of C3 and C4 species is almost indistinguishable. However, close inspection of these figures at source and correspondence with several authors revealed a number of errors. When all unreliable figures were discarded, the maximum growth rate for C3 stands fell in the range 34–39 g m−2 d−1 compared with 50–54 g m−2 d−1 for C4 stands. Maximum growth rates averaged over the whole growing season showed a similar difference: 13 g m−2 d−1 for C3 and 22 g m−2 d−1 for C4. These figures correspond to photosynthetic efficiencies of approximately 1·4 and 2·0%.

Wounding of aspen roots promotes suckering

2004 ◽  
Vol 82 (3) ◽  
pp. 310-315 ◽  
Author(s):  
Erin C Fraser ◽  
Victor J Lieffers ◽  
Simon M Landhäusser
Keyword(s):  
Populus Tremuloides ◽  
Growth Rates ◽  
Growing Season ◽  
Organic Layer ◽  
Trembling Aspen ◽  
Layer Depth ◽  
Injury Type ◽  
Organic Layers ◽  
Root Injury ◽  
Root Sucker

In early May, 1-m sections of trembling aspen (Populus tremuloides Michx.) roots in a forest cutblock were carefully exposed and examined for damage. Undamaged roots were subjected to one of three wounding treatments (scrape, sever, or uninjured control) and were then reburied to either the full normal organic layer depth or to one third of the normal depth. Following one growing season, the roots were reexposed and assessed for aspen sucker numbers and growth rates. Results indicate that injured roots produced suckers nearly twice as often as uninjured roots. Further, injured roots produced more suckers per root, and these suckers were taller and had greater leaf area. Roots buried under shallow organic layers also generated more suckers, regardless of injury type. The side of injury (distal or proximal) did not affect any of the measured variables. The present study suggests that moderate wounding of aspen roots increases initial sucker numbers and growth rates.Key words: trembling aspen, root sucker, root injury, regeneration.

scholarly journals Rust and leaf spot diseases on American elderberry plants

2017 ◽  
Author(s):  
◽  
Kaley Hensel
Keyword(s):  
Leaf Spot ◽  
Dry Weight ◽  
Growing Season ◽  
Significant Loss ◽  
Leaf Wetness ◽  
Conservative Estimate ◽  
Sambucus Nigra ◽  
Shoot Dry Weight ◽  
Harvest Dates ◽  
High Level

Elderberry rust (Puccinia sambuci Schewin.) Arthur (=P. bolleyana) and leaf spot diseases are frequently found in commercial American elderberry (Sambucus nigra L. subsp. canadensis L.) plantings throughout the growing season in Missouri. Thus, studies were conducted to ascertain if rust infections affect plant growth, fruiting, or berry puree quality. Rust symptoms were observed in early April at 9 to 18[degrees] C, [greater than or equal to] 3 h leaf wetness, and [greater than or equal to] 85% relative humidity. When young, potted elderberry plants averaged 3 to 6 rust pustules/plant, vegetative growth was not adversely affected. However, field-grown elderberry plants heavily infected with rust (137 pustules/cane) lost nearly twice as many leaves as controls during the growing season, indicating rust-induced defoliation. Shoot dry weight of these heavily infected canes was also 32% less than that of controls. First and last harvest dates were advanced by the high level of rust infection on 'Wyldewood' elderberry canes, but not by low pustules numbers ([less than] 6 pustules/plant) on 'Bob Gordon' or 'Ozark' plants. Similarly, berry yields were not significantly different at low infection levels, even though rust-infected 'Bob Gordon' plants had a 31% reduction in yield with an estimated $440/ha loss of income. Heavily-infected 'Wyldewood' canes had a significant loss in berry yield (47%) and potential income ($2,295/ha), assuming a conservative estimate of five canes/plan. In another study, Colletotrichum was isolated from elderberry leaf spot lesions and identified before subsequent re-inoculation of elderberry plants with this pathogen. Three species of Colletotrichum (C. salicis Funkel, C. kahawae subsp. ciggaro Wollenw., and C. aenigma C.M. Tian and Z. Li) were putatively identified as being casual agents of leaf spot indicating the diversity of species within this genus on elderberry plants.

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