scholarly journals Inflorescence Initiation in Lolium Temulentum L. IX. Some Chemical Changes in the Shoot Apex at Induction

1967 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
AHGC Rijven ◽  
LT Evans

Plants of L. temulentum were induced to flower by exposure to 1 long day. Shoot apices harvested from vegetative plants prior to the long�day exposure (day I) and others harvested on days IV and VI were analysed for length, fresh weight, total and residual (after extraction for solubles and lipids) dry weight, total and residual nitrogen content, residual phosphorus, and RNA and DNA phosphorus content. Cell number per apex was also established for two harvests.

Weed Science ◽  
1978 ◽  
Vol 26 (1) ◽  
pp. 51-57 ◽  
Author(s):  
M. B. Awang ◽  
T. J. Monaco

Germination studies on camphorweed [Heterotheca subaxillaris(Lam.) Britt. & Rusby] revealed that freshly harvested disk achenes germinated best at 17.5 C (88%) while ray achenes were dormant. Camphorweed seed from disk achenes also germinated at temperatures as low as 3 C. Seedlings grown under long-day conditions at 23 C day and 8 C night temperatures for 144 days elongated at the rate of 0.18 cm/day. Plants grown under short-day conditions at the same temperature regime elongated at the rate of 0.06 cm/day. Total leaf surface area, fresh weight, and dry weight of shoots of plants grown under long days were at least 1.5 times greater than plants grown under short day conditions. Camphorweed, regardless of size and age, survived a 2-h exposure at −5 C. All plants in the rosette stage survived at −15 C in the freezer and an overnight temperature of −11.7 C in the field, whereas larger plants were killed at these temperatures. Stage of growth was an important factor in the herbicidal control of camphorweed. Plants in the rosette stage were generally more susceptible to herbicides than older plants. Simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] at 3.4 kg/ha, paraquat (1,1′-dimethyl-4,4′-bypyridinium ion) at 0.6 kg/ha, methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] at 5.0 kg/ha, and a formulated mix of diuron [3–3,4-dichlorophenyl)-1,1-dimethylurea] and terbacil (3-tert-butyl-5-chloro-6-methyluracil) at 4.5 kg/ha provided adequate control of camphorweed in the rosette stage. Asulam (methyl sulfanilylcarbamate) at 2.2 or 4.5 kg/ha applied alone did not control camphorweed in the rosette form but was more effective on older plants. Various combinations of these herbicides were generally effective at both stages of growth.


1958 ◽  
Vol 36 (1) ◽  
pp. 45-49
Author(s):  
S. Fedoroff ◽  
R. Altschul

In an attempt to elucidate the increase of growth promotion of tissue cultures by extracts obtained from tissues chilled before extraction, determinations of nitrogen content were made on (a) fresh, and chilled chick embryos, (b) extracts prepared from fresh and chilled chick embryos, (c) fresh and chilled human placenta, (d) extracts prepared from fresh and chilled human placenta.There was no difference in dry weight, nitrogen content, phosphorus content, and nitrogen: phosphorus ratio between chilled and fresh chick embryos and chilled and fresh human placenta. There was, however, a significant difference in the nitrogen content of the extracts prepared from fresh and from chilled tissues, It is suggested that chilling of tissues for 7 days at + 4 °C. prior to extraction may render the cells more easily destructible during extraction, and thus supply a better yield of nutritive substances.


1969 ◽  
Vol 20 (6) ◽  
pp. 1073 ◽  
Author(s):  
DS Letham

The respiration rates and tissue contents of nitrogen, phosphorus, and titratable acidity were determined for apple fruit from trees receiving differential fertilizer treatments U, N, P, NP, and NPK (U, no fertilizer; N, 2 lb ammonium sulphate; P, 4 1b superphosphate; and K, 1 Ib potassium sulphate, per tree per year). The results obtained (expressed on a dry weight basis) are summarized as follows: Respiration rate: N > NP = NPK = U > P. Total nitrogen content: NPK > NP = N > U = P. Ethanol-insoluble nitrogen content: NPK = NP = N > U = P. Ethanol-soluble nitrogen content: NPK > NP = N > U = P. Phosphorus content : P > NP = NPK > U > N. Titratable acidity content: NPK > N > NP = U > P. The incidence of internal breakdown in stored fruit from these treatments has positively correlated with respiration rate per cell and negatively correlated with phosphorus content. Phosphorus content was negatively correlated with cell volume and respiration rate. Mechanisms by which phosphorus content might regulate the incidence of internal breakdown are discussed.


2017 ◽  
Vol 9 (1) ◽  
pp. 215-221 ◽  
Author(s):  
Ikbal Ikbal ◽  
Mukesh R Jangra ◽  
K. M. Sarim ◽  
V.K. Sikka

Conjugation between microsymbiont was used to create genetic variations in rhizobia for diverse rabi legumes (chickpea, pea and lentil) with better characteristics in nodulation and nitrogen fixation process. Ten antibiotics were used as selectable markers for the screening of twenty four bacterial strains to be used in mating experiments for obtaining transconjugants. All bacterial strains were sensitive to gentamycin and resistant to streptomycin, kanamycin and sulphanilamide. Total five fusants were obtained from each rhizobial cross combination with the help of electro-poration. Modified transconjugants, rhizobial strains had promiscuous infection with 50-122% more nodules showed significant increase in shoot fresh weight, dry weight and total nitrogen content in chickpea, pea and lentil plants. Electrofusantsrhizobial strains improved shoot nitrogen content up to 67% in lentil and 54% in pea and chickpea plants. The amount of nitrogen fixed in chickpea was highest (3.71gm) by transconjugants DP-C6- HLN followed by DP-C6-HP14 (3.56gm). Transconjugants DP-HP14-HLN fixed the highest amount of nitrogen (3.92gm) in pea and 4.06gm in lentil plants. Plasmids were also analyzed in order to characterize their role in the evolution of rhizobial symbionts and their involvement in symbiotic behaviour. The developed Rhizobium strains with improved symbiotic association and ability to infect across strict specificity for host legumes would be of great help for the farming community at large.


1961 ◽  
Vol 14 (4) ◽  
pp. 552 ◽  
Author(s):  
AHGC Rijven ◽  
R Cohen

Ears of field-grown wheat were harvested on 12 occasions between anthesis and ripeness. Fresh weight, dry weight, and total nitrogen content of selected grains were determined.


2021 ◽  
Vol 16 (1) ◽  
pp. 170-185
Author(s):  
Fatma S Moursy ◽  
Doaa AM Gad ◽  
Dalia Adly ◽  
Ihab I Sadek

This study investigated the effects of two organic fertilizer (compost tea and humic acid) compared to chemical fertilizer on plant growth, productivity, pests and predatory insects associated with eggplant Solanum melongena var. Black beauty under net house in 1st of April at 2019 and 2020 seasons. Application of fertilizers through fertigation enhanced significantly number of leaves, stem fresh weight, average fruit weight and total fruit yield. Moreover, stem diameter, nitrogen content in leaves (%), phosphorus content in leaves (%), potassium content in leaves (%), number of fruits and total yield were enhanced significantly due to using compost tea. However, using the humic acid cause a significant enhancement in number of shoots, number of leaves, stem diameter and leaves fresh weight. In addition, application of compost tea through the fertigation cause a significant superiority in number of shoots, nitrogen content in leaves (%), phosphorus content in leaves (%), potassium content in leaves (%), number of fruits, average fruit weight and total yield. The highest significant values of leaves fresh weight and stem dry weight were mainly due using humic acid through foliar application. Three main pest species and seven different predators' species were recorded associated with pests on eggplant. The application of foliar and fertigation compost tea increased pest populations significantly compared with humic acid and control. But also, increase the predators' population.


1958 ◽  
Vol 36 (1) ◽  
pp. 45-49
Author(s):  
S. Fedoroff ◽  
R. Altschul

In an attempt to elucidate the increase of growth promotion of tissue cultures by extracts obtained from tissues chilled before extraction, determinations of nitrogen content were made on (a) fresh, and chilled chick embryos, (b) extracts prepared from fresh and chilled chick embryos, (c) fresh and chilled human placenta, (d) extracts prepared from fresh and chilled human placenta.There was no difference in dry weight, nitrogen content, phosphorus content, and nitrogen: phosphorus ratio between chilled and fresh chick embryos and chilled and fresh human placenta. There was, however, a significant difference in the nitrogen content of the extracts prepared from fresh and from chilled tissues, It is suggested that chilling of tissues for 7 days at + 4 °C. prior to extraction may render the cells more easily destructible during extraction, and thus supply a better yield of nutritive substances.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1092a-1092
Author(s):  
David C. Annis ◽  
Terri Starman

Flowers of Craspedi a uniflora (Billy Buttons), a New Zealand annual plant, have been introduced recently into the U.S.A. florist market. Craspedia is relatively unknown in the U.S.A., but is beginning to be utilized by florists as a cut flower and has potential for specialty cut flower production. Craspedia uniflora cut flowers were grown from seed in an inflated, double-layer, polyethylene greenhouse. Short day (SD) and long day (LD) photoperiod treatments were applied by daylength reduction via black cloth and night interruption lighting, respectively. Treatments began 10 weeks after sowing (15 leaf stage) and continued until harvest. Gibberellic acid was applied as a single foliar spray to runoff at 0 and 500 mg·liter-1 at initiation of photoperiod treatment. Long day treatment reduced days to anthesis, increased flower number, and decreased stem length and plant fresh weight. Gibberellic acid (500 mg·liter-1) increased foliage height under both photo period treatments and increased plant dry weight under LD but reduced dry weight under SD treatment. Flower fresh weight, diameter and bud number were not affected by treatment.


1965 ◽  
Vol 16 (4) ◽  
pp. 617 ◽  
Author(s):  
D Martin ◽  
NS Stenhouse ◽  
TL Lewis ◽  
J Cerny

A block of Jonathan apple trees were treated for 4 years as individual tree plots with nil, nitrogen, nitrogen + phosphorus, and nitrogen + potassium applied as sprays during two periods, either in spring before bud differentiation or after bud differentiation in mid January. The treatments had no effect on the levels of phosphorus or potassium in the fruit. Spring applications had no significant effect on the nitrogen content, but summer applications a marked one, though there was no evidence of a cumulative build-up or any effect on cell number per fruit. These increases in nitrogen content were accompanied by small increases in breakdown level, but only when an inherent seasonal susceptibility existed. Only a diminishing proportion of the additional nitrogen was incorporated into the protein fraction, and the preclimacteric respiration rate was not affected significantly by the increase in protein. Except for percentage dry matter, there was a wide variation in the values between trees of the variables, which permitted a multiple regression analysis. The regression of breakdown and cell volume was positive and highly significant in all years. Except for the year of very low incidence, there was a significant positive relationship between breakdown and nitrogen level, and a consistent negative relationship between breakdown and phosphorus level which was significant in the years of high breakdown incidence. No relationship could be shown between breakdown and potassium. Similar results were obtained by using a percentage fresh weight or percentage dry weight basis for the nitrogen, phosphorus, and potassium contents, or by using actual values or a log (x + 1) transformation for the variables, though there were some advantages in using the latter. The results suggest an important physiological interaction between breakdown and cell volume, nitrogen, and phosphorus.


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