scholarly journals Photosynthesis and Rubber Production in Transgenic Guayule (Parthenium argentatum, Gray) in Response to Cold Night Temperatures

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 770C-770 ◽  
Author(s):  
Maren E. Veatch* ◽  
Dennis T. Ray
Keyword(s):  
Photosynthetic Apparatus ◽  
Dry Weight ◽  
Parthenium Argentatum ◽  
Cold Night ◽  
Lower Growth ◽  
Cold Temperatures ◽  
Rubber Production ◽  
Warm Night ◽  
Nighttime Temperatures ◽  
Set Up

Rubber production in guayule (Parthenium argentatum, Gray) is highest in the winter months. It has been suggested that lower nighttime temperatures stimulate rubber production. Higher rubber production could be the result of up regulation of the enzymes involved in rubber synthesis, or acclimation of the photosynthetic apparatus to cold temperatures, making photosynthates available for rubber production when the plants are not actively growing, or a combination of the two factors. The effect of low night temperatures on photosynthesis and rubber production was examined in greenhouse grown plants. The experiment was set up as a split plot with different sub plots enclosed in heated or non-heated containers during the night. Those placed in non-heated containers were exposed to the ambient night temperatures of the greenhouse. During the growing season, growth was measured as change in height, and midday and diurnal photosynthetic measurements were collected. At harvest fresh and dry weight of both roots and shoots were taken. Resin and rubber were then extracted with acetone and cyclohexane respectively. Midday photosynthesis was as high or higher in cold night plants than in the warm night plants. In addition, the cold night treatment had lower growth than the warm night treatment. Percent resin and rubber were significantly higher in both shoots and roots of cold night plants, as was the overall yield of rubber. An increase in photosynthetic rate in the cold night treatment, without the concomitant increase in growth seen in the warm night treatment, could account for the increase in rubber production during the winter months.

scholarly journals Agronomic performances of Pak Choi grown with different soil cover

2015 ◽  
Vol 33 (2) ◽  
pp. 261-266 ◽  
Author(s):  
Márcia M Echer ◽  
Graciela M Dalastra ◽  
Tiago L Hachmann ◽  
Elcio S Klosowski ◽  
Vandeir F Guimarães
Keyword(s):  
Soil Cover ◽  
Block Design ◽  
Dry Weight ◽  
Bare Soil ◽  
Production Traits ◽  
Pak Choi ◽  
Randomized Block Design ◽  
Black Plastic ◽  
Growing Conditions ◽  
Set Up

An important aspect in the cultivation of vegetables is the quality of the product to be marketed, free from dirt and damage and the practice of mulching could be an option, but there is scarse information. The aim of this study was to evaluate the influence of mulching on the production traits of three cultivars of Pak Choi. The experiment was set up during March to May 2013 using a split plot randomized block design, with four replications. Soil cover treatments (white agrotextile, black agrotextile, black plastic, silver plastic, tifton straw and bare soil) were arranged in the plots, and three cultivars of Pak Choi (Green Pak Choi, White Pak Choi and Chingensai Natsu Shomi) in subplots. Height and diameter of shoots, number of leaves, fresh weight of the head and petiole, base diameter, dry weight of stem, petiole, and leaf were evaluated thirty-five days after transplantation. The total dry weight and leaf area were measured, and then we estimated the yield. There was a significant effect of soil cover and cultivar. In general, the cover with synthetic materials showed higher values on production of Pak Choi. The cultivar White Pak Choi was better adapted to the growing conditions, with an average yield of 57.78 t/ha.

scholarly journals Reproducibility of suppression of Pythium wilt of cucumber by compost

2014 ◽  
Vol 23 (3) ◽  
pp. 236-245 ◽  
Author(s):  
Mauritz Vilhelm Vestberg ◽  
Sanna Kukkonen ◽  
Päivi Parikka ◽  
Dan Yu ◽  
Martin Romantschuk
Keyword(s):  
Raw Materials ◽  
Dry Weight ◽  
Shoot Height ◽  
Bacterial Diseases ◽  
Sphagnum Peat ◽  
Shoot Dry Weight ◽  
Suppressive Capacity ◽  
The Difference ◽  
Set Up

There is increasing global interest in using compost to suppress soil-borne fungal and bacterial diseases and nematodes. We studied the reproducibility of compost suppressive capacity (SC) against Pythium wilt of cucumber using nine composts produced by the same composting plant in 2008 and 2009. A bioassay was set up in a greenhouse using cucumber inoculated with two strains of Pythium. The composts were used as 20% mixtures (v:v) of a basic steam-sterilized light Sphagnum peat and sand (3:1, v:v). Shoot height was measured weekly during the 5-week experiment. At harvest, the SC was calculated as the % difference in shoot dry weight (DW) between non-inoculated and inoculated cucumbers. The SC was not affected by year of production (2008 or 2009), indicating reproducibility of SC when the raw materials and the composting method are not changed. Differences in shoot height were not as pronounced as those for shoot DW. The results were encouraging, but further studies are still needed for producing compost with guaranteed suppressiveness properties.

scholarly journals The effect of molybdenum and boron in soil on the growth and photosynthesis of three soybean varieties

2011 ◽  
Vol 51 (No. 5) ◽  
pp. 197-205 ◽  
Author(s):  
P. Liu ◽  
Y.S. Yang ◽  
G.D. Xu ◽  
Y.H. Shi ◽  
Y.A. Yang ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Genotypic Variation ◽  
Dry Weight ◽  
Photosynthesis Rate ◽  
Growth Stages ◽  
Pot Experiments ◽  
Tolerant Plant ◽  
Set Up ◽  
System Volume

This paper presents a study on growth and photosynthesis response of soybean to Mo and/or B in soil. Pot experiments were set up to examine the effect of Mo and/or B on growth and photosynthesis of three soybean varieties with four treatments (control, +Mo, +B, +[Mo + B]) at various growth stages. The study showed that Mo and/or B increased main length, system volume and dry weight of the roots, aboveground biomass, leaves’ photosynthesis rate of soybean. The variation and interaction between Mo and B in soil was explored with regard to their impact on soybean growth and photosynthesis. There were some dissimilarity in growth and photosynthesis in the plants between the supplements of Mo and B in the soil, and the interrelation between Mo and B in plant and was co-supplementary to each other. Therefore, growth and photosynthesis of the soybean with Mo and B treatments were much more improved than those with Mo or B alone. Besides, some genotypic variation was found in three soybean varieties, in which Zhechun III was the most sensitive and 3811 the most tolerant plant to Mo and B.

scholarly journals Light reduction and moisture stress: effects on growth and water relations of western larch seedlings

1985 ◽  
Vol 15 (1) ◽  
pp. 72-77 ◽  
Author(s):  
Nan C. Vance ◽  
Steven W. Running
Keyword(s):  
Stomatal Closure ◽  
Biomass Accumulation ◽  
Dry Weight ◽  
Moisture Stress ◽  
Western Larch ◽  
Light Reduction ◽  
Stress Effects ◽  
Reduced Height ◽  
Terminal Bud ◽  
Nighttime Temperatures

Ten-week-old western larch (Larixoccidentalis Nutt.) seedlings were grown in a greenhouse under 70, 37, and 27% full sunlight from late July to early October. In August, seedlings under each light treatment were repetitively water stressed until predawn leaf water potential (Bψ1) reached one of three levels: no stress (> −0.4 MPa), moderate stress (−0.7 to −1.0 MPa), and severe stress (−1.5 to −1.8 MPa). Moisture stressing significantly reduced height and diameter of seedlings grown under 70% light. Light reduction reduced shoot and root biomass accumulation. A positive linear relation was found between root dry weight and light intensity. The largest seedlings (on a weight basis) received the highest light, were unstressed, and had the lowest shoot/root ratios. Terminal bud set was not affected by light reduction or moisture stressing but occurred under a 14-h photoperiod and reduced nighttime temperatures. Stressed and shaded seedlings had significantly reduced diurnal K1 and stress-cycled seedlings showed an adjustment to stressing. The K1 of unstressed seedlings was correlated with humidity deficit (ABHD), and K1 of stressed seedlings, with Bψ1, and ABHD. Maximum K1 declined with decreasing Bψ1, but not to a level indicating complete stomatal closure.

Variation in oil concentration and economic return from tea-tree (Melaleuca alternifolia Cheel) oil

1990 ◽  
Vol 30 (5) ◽  
pp. 675 ◽  
Author(s):  
GJ Murtagh ◽  
RJ Etherington
Keyword(s):  
Dry Weight ◽  
Production Costs ◽  
Melaleuca Alternifolia ◽  
Tea Tree ◽  
Percentage Points ◽  
Average Production ◽  
Oil Concentration ◽  
The Mean ◽  
Set Up ◽  
Returns On Investment

The oil concentration in tea-tree (Melaleuca alternifolia Cheel) twigs was measured over 8 consecutive days during November 1987, and over 10 out of 12 consecutive days in January 1989. The oil concentration, measured in units of volume of oil per unit dry weight of twigs (v/DW), varied markedly between successive days, from 2.9-1.8% v/DW (a 38% decrease) to 1.8-3.4% v/DW (a 89% increase). The reason for such variation is unknown but it had a pronounced effect on the profitability of growing the crop. The profit, which was expressed as a return on the total set-up cost of $A17 2591ha, was estimated for each of the measured oil concentrations and fixed values of biomass yield, the price of oil and average production costs. The extreme daily variations in oil concentration mentioned above caused the return on investment to decline by 11 percentage points and increase by 16 points, respectively. When measured at the same site, the mean oil concentration increased from 3.1% vPW in November 1987 to 5.8% v/DW in January 1989. As a consequence, the respective mean returns on investment increased from 0 to 26%.

scholarly journals Cover Crops, Mulch Lower Night Temperatures in Citrus

2000 ◽  
Vol 1 (1) ◽  
pp. 6
Author(s):  
N. V. O'Connell ◽  
R. L. Snyder
Keyword(s):  
Cover Crops ◽  
Cost Effective ◽  
Frost Damage ◽  
San Joaquin Valley ◽  
Effective Management ◽  
Cold Temperatures ◽  
Temperature Forecast ◽  
Economic Threat ◽  
Forecast Models ◽  
Nighttime Temperatures

Winter often brings cold temperatures that can damage fruit or foliage in the San Joaquin Valley, posing an economic threat to citrus producers. Our experiments show that cover crops or mulch can lower minimum nighttime temperatures 0.9°F to 2.2°F in orchards, increasing the threat of freeze (frost) damage. Wind machines are typically used to protect commercial acreage from frost by mixing warmer air aloft with colder air near the surface, thus maintaining warmer minimum temperatures within the orchard. In locations where wind machines are not cost effective, management of the orchard floor is even more important. By using temperature forecast models that adjust for cover crops and mulches, growers can use wind machines more efficiently. Regardless, the decision to use cover crops must take into account all of their cultural benefits and drawbacks.

scholarly journals Nitrogen and Crude Proteins in Beetroot (Beta vulgaris var. conditiva) under Different Fertilization Treatments

2012 ◽  
Vol 40 (2) ◽  
pp. 215 ◽  
Author(s):  
Marko PETEK ◽  
Mirjana HERAK CUSTIC ◽  
Nina TOTH ◽  
Sanja SLUNJSKI ◽  
Lepomir COGA ◽  
...  
Keyword(s):  
Protein Content ◽  
Beta Vulgaris ◽  
Crude Protein ◽  
Latin Square ◽  
Storage Period ◽  
Dry Weight ◽  
Fresh Weight ◽  
Mineral Fertilization ◽  
Stable Manure ◽  
Set Up

The research aim was to determine the influence of different organic and mineral fertilization treatments and post-harvest treatments on the content of nitrogen and crude proteins in the edible part of beetroot (Beta vulgaris var. conditiva). A field trial (2003-2005) was set up in a hilly part of Croatia according to the Latin square method with four types of fertilization (control, 50 t ha-1 stable manure, 500 and 1000 kg ha-1 NPK 5-20-30), while treatments involved harvested fresh beetroot and stored fresh beetroot. The highest dry weight (DW) content was determined in climatologically favourable 2004 (average 14.8% DW) and in the treatment with 1000 kg ha-1 NPK 5-20-30 (15.6% DW) in harvested beetroot. In 2004 and 2005, the highest levels of nitrogen and crude proteins in harvested beetroot were determined in the treatment with 1000 kg ha-1 NPK 5-20-30 (2.41 and 2.43 g N kg-1 in fresh weight and 15.07 and 15.21 g crude proteins kg-1 in fresh weight, respectively). Regardless of fertilization treatment or studied year, nitrogen and crude protein contents were higher in stored than in harvested beetroot, by 12% on average. The lowest crude protein content was determined in treatment with stable manure what confirmed that protein content decreased by organic fertilization. It can be concluded that beetroot lost some water during the storage period, which increased its content of nitrogen and crude proteins in fresh weight and thus increased the nutritional quality of beetroot as a functional food.

Competition, Growth Rate, and CO2Fixation in Triazine-Susceptible and -Resistant Smooth Pigweed (Amaranthus hybridus)

Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 438-444 ◽  
Author(s):  
William H. Ahrens ◽  
E. W. Stoller
Keyword(s):  
Growth Rate ◽  
Dry Weight ◽  
Dry Matter Accumulation ◽  
Lower Growth ◽  
Amaranthus Hybridus ◽  
Relative Growth ◽  
Lower Growth Rate ◽  
Net Assimilation ◽  
Synthetic Capacity ◽  
Smooth Pigweed

Triazine-susceptible (S) and -resistant (R) biotypes of smooth pigweed (Amaranthus hybridusL.) were grown in the field under competitive conditions at varying initial proportions of S and R plants. R plants were less competitive than S plants as measured by accumulation of total above-ground dry weight and seed dry weight. S and R plants were also grown in the field under non-competitive conditions at 100, 40, and 10% light. Growth rate at 10% light did not differ between S and R plants. At the two higher light intensities, dry-matter accumulation 11 weeks after seeding was about 40% less in the R plants. At 100% light, relative growth rate and net assimilation rate were lower in the R plants by about 3.5 and 19%, respectively. The light- and CO2-saturated rates of CO2fixation in intact leaves of glasshouse-grown R plants were 20% less than those in S plants. An apparent 10 and 20% greater number of chlorophyll molecules per photosystem II reaction center in R plants (as compared with S plants) grown in the field at 40 and 100% light, respectively, did not explain differences between the S and R biotypes in photo synthetic capacity. The S and R plants did not differ in specific leaf weight or chlorophyll content on a leaf-area basis. Lower growth rate of R plants may be responsible for inferior competitive ability of R biotypes and could be the result of an impaired photosynthetic capacity.

scholarly journals Growth and Development of Stevia Cuttings During Propagation with Hormones in Different Months of the Year

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 294
Author(s):  
Ma Claudia Castañeda-Saucedo ◽  
Ernesto Tapia-Campos ◽  
Jessica del Pilar Ramírez-Anaya ◽  
Jaqueline Beltrán
Keyword(s):  
Root Development ◽  
Dry Weight ◽  
Growth Hormones ◽  
Shoot Biomass ◽  
Total Biomass ◽  
Different Seasons ◽  
Number Of Leaves ◽  
Growth Development ◽  
Set Up ◽  
Leaf Dry Weight

Stevia is an important non-caloric sweetener that has health-beneficial properties. The objective is to evaluate growth, development, and rooting of stevia plants during different seasons of the year using growth hormones. Eight experiments were set up in Ciudad Guzman, Jalisco, Mexico, with three treatments (T): T1, indol-3 butyric acid (IBA) 7.4 mM; T2, alphanaphthylacetamide (ANA) 6.4 mM + IBA 0.3 mM; and T3, control. The variables evaluated were rooted plantlets, plant height, root length, number of leaves, stem diameter, leaf dry weight, stem dry weight, root dry weight, leaf area, shoot biomass, total biomass, as well as development and growth indexes. Four samplings were conducted in each experiment. The results show that the most appropriate months for propagating stevia cuttings are February, March, April, May, and July, when 96% to 99% of the cuttings rooted. The hormones had the best results related to production of root development. The control was outstanding only in variables related to production of shoot biomass and not to root development. It is concluded that stevia can be propagated vegetatively using cuttings treated with IBA 7.4 mM or ANA 6.4 mM + IBA 0.3 mM, preferable in the period from February to July, with the exception of June.

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