The primary productivity and physiology of Ceratophyllum demersum. I. Gross macro primary productivity

1969 ◽  
Vol 20 (2) ◽  
pp. 115 ◽  
Author(s):  
JL Carr

An artificial laboratory stream was used to study production in Ceratophyllum demersum under various conditions of light intensity, light quality, day length, and water flow. An incandescent illumination of 1500 f.c. over a 12 hr day length gave optimum production. Moderate amounts of red light gave the greatest increase in wet weight but full red light was inhibitory. Blue light, rather than white light, controlled internode length, but small amounts of red light did not cause any inhibition of this internode lengthening. Production appeared to increase with water flows (current) up to 0.54 cm/sec, but this could have been due to temperature effects. Bud formation was arrested in the slowest water flow tested, viz. 0.46 cm/sec. This suggests that vegetative propagation is retarded by slow water flows. Neither length nor the number of leaves per node showed any response to current or temperature.

1969 ◽  
Vol 20 (2) ◽  
pp. 127 ◽  
Author(s):  
JL Carr

Photosynthesis in Ceratophyllum demersum has been measured in a Warburg respirometer containing a diethanolamine carbon dioxide buffer. Except in May, the photosynthetic activity of leaves is always greater than the buds. Production in the leaves rises from the minimum to the maximum during the period from May to October (winter to spring), probably as a response to increasing day length, while that in the buds remains practically constant throughout the year. With the onset of warmer temperatures in summer, vegetative growth declines. It is concluded that turions of Ceratophyllum are resistant not to cold but to heat and high light intensities of summer. Leaf photosynthesis occurs within a temperature range of 10-30�c and reaches a maximum at 20°C. The extracted chlorophyll content is greatest in plants collected from the surface of the lake and the ratio of chlorophyll a to chlorophyll b reaches a peak at 5 m depth. In Ceratophyllum it is suggested that the phenomenon of chromatic adaptation is occurring, and it is concluded that Ceratophyllum is a shade plant, being adapted to the quantity as well as the quality of light. Production in the leaves is depressed on the surface of the water and is greatest between 2.5 and 5.0 m depth. Also it is suggested that the compensation point for Ceratophyllum in Lake Ohakuri cannot be at a depth of much greater than 8 metres. The photosynthetic activity expressed on a dry weight basis is the greatest in the first mature leaves (6 cm behind the apex) and becomes progressively lower in the buds, leaves (1 ft behind the apex), and the stems. Furthermore, the rate of gross photosynthesis in leaves, buds, or stems exceeds the rate of respiration at all months of the year. Respiration in the dark is greater in the presence of carbon dioxide than in its absence. It is also greater in the dark than in the light. The rate of photosynthesis in Ceratophyllum is greatest at pH 5.0. From this, it is concluded that photosynthesis takes place at the greatest rate in a medium containing free CO2 rather than the bicarbonate ion. With only bicarbonate ion carbon dioxide present photosynthesis will still take place, although it is at a much lower rate.


2020 ◽  
Vol 13 (2) ◽  
pp. 83-92 ◽  
Author(s):  
A. Adam

SummaryEnhancement of the resistance level in plants by rhizobacteria has been proven in several pathosystems. This study investigated the ability of four rhizobacteria strains (Pseudomonas putida BTP1 and Bacillus subtilis Bs2500, Bs2504 and Bs2508) to promote the growth in three barley genotypes and protect them against Cochliobolus sativus. Our results demonstrated that all tested rhizobacteria strains had a protective effect on barley genotypes Arabi Abiad, Banteng and WI2291. However, P. putida BTP1 and B. subtilis Bs2508 strains were the most effective as they reduced disease incidence by 53 and 38% (mean effect), respectively. On the other hand, there were significant differences among the rhizobacteria-treated genotypes on plant growth parameters, such as wet weight, dry weight, plant height and number of leaves. Pseudomonas putida BTP1 strain was the most effective as it significantly increased plant growth by 15-32%. In addition, the susceptible genotypes Arabi Abiad and WI2291 were the most responsive to rhizobacteria. This means that these genotypes have a high potential for increase of their resistance against the pathogen and enhancement of plant growth after the application of rhizobacteria. Consequently, barley seed treatment with the tested rhizobacteria could be considered as an effective biocontrol method against C. sativus.


Author(s):  
Nora Augustien ◽  
Pawana Nur Indah ◽  
Purnawati Arika ◽  
Irsyad Irsyad ◽  
Hadi Suhardjono

Indian mustard plants are the main vegetable crops consumed by urban communities. The need for this vegetable increases along with the increase in culinary tourism in each region and the government's appeal on sustainable food home. One effort made to meet the needs of vegetable mustard in urban areas can be cultivated using polybags. The main problem of vegetable cultivation on polybags is the availability of soil media. To overcome the limitations of soil media it is attempted to substitute it with organic litter enriched with MOL (local microorganisms). The purpose of research is to find the right combination of planting media for mustard plants. The results showed that the composition of K7 = soil: compost: litter of hay: litter of maize (2: 1: 1: 1) best on plant length, number of leaves, length of root leaves and number of roots while the wet weight of mustard plant (g) K7 = soil: compost: litter of maize: litter of corn (2: 1: 1: 1) and K8 = soil: compost: litter of maize: litter of maize: cocopeat (2: 1: 1: 1: 1) or soil: compost + urea. Increased weights of wet mustard by 63% compared to soil media and 20% compared to soil composition: compost + urea. Organic straw in the form of straw: litter of corn stalk: cocopeat enriched with MOL are able to become ready-made planting media on the cultivation of indian mustard plants in polybags.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 447d-447
Author(s):  
Meriam Karlsson ◽  
Jeffrey Werner

Nine-week-old plants of Cyclamen persicum `Miracle Salmon' were transplanted into 10-cm pots and placed in growth chambers at 8, 12, 16, 20, or 24 °C. The irradiance was 10 mol/day per m2 during a 16-h day length. After 8 weeks, the temperature was changed to 16 °C for all plants. Expanded leaves (1 cm or larger) were counted at weekly intervals for each plant. The rate of leaf unfolding increased with temperature to 20 °C. The fastest rate at 20 °C was 0.34 ± 0.05 leaf/day. Flower buds were visible 55 ± 7 days from start of temperature treatments (118 days from seeding) for the plants grown at 12, 16, or 20 °C. Flower buds appeared 60 ± 6.9 days from initiation of treatments for plants grown at 24 °C and 93 ± 8.9 days for cyclamens grown at 8 °C. Although there was no significant difference in rate of flower bud appearance for cyclamens grown at 12, 16, or 20 °C, the number of leaves, flowers, and flower buds varied significantly among all temperature treatments. Leaf number at flowering increased from 38 ± 4.7 for plants at 12 °C to 77 ± 8.3 at 24 °C. Flowers and flower buds increased from 18 ± 2.9 to 52 ± 11.0 as temperature increased from 12 to 24 °C. Plants grown at 8 °C had on average 6 ± 2 visible flower buds, but no open flowers at termination of the study (128 days from start of treatments).


2010 ◽  
Vol 10 (5) ◽  
pp. 831-840 ◽  
Author(s):  
Ángel De Miguel ◽  
Eloy García ◽  
Irene De Buestamante

Virtual water is defined as the water needed to produce a product. We can use virtual water flow calculations to estimate the water efficiency of a country, as well as its economic dependence on water resources. Former studies on this area have focused on quantifying the virtual water flows between countries, in an international context. In this study we reduce the action framework to regions within a country, determining the virtual water balance between two Spanish regions: Castilla-La Mancha and Murcia. In 2004, Castilla-La Mancha exported to Murcia 2,453,442 tons of commercial products, from which 1,191,628 tons were agricultural goods. In terms of virtual water, it means 1,365 hm3, including food-processing, and industrial products. It is necessary to add 350 hm3 to the result, because of the water transfer (Tajo-Segura transfer) between the rivers basins of these regions, so the final virtual water number, in 2004, was 1,715 hm3. The other way round, Murcia exported in 2004 2,069,000 tons of products, from which 490,351 tons were agricultural goods. That supposes 712 hm3 of virtual water. Virtual water flow is unbalanced and displaced towards Murcia with a difference of 1,003 hm3.


2018 ◽  
Vol 14 (1) ◽  
pp. 439
Author(s):  
Alfrida ., Maninggolang ◽  
Jeany Sh. Polii-Mandang ◽  
Wenny ., Tilaar

This study aims to know the effect of Benzyl Amino Purine (BAP) and Coconut Water on shoot bud growth and Broccoli Sulforaphane content (Brassica oleracea L. var italic Plenck). The study was conducted in the laboratory of Biotechnology Department of Aquaculture, Faculty of Agriculture of Sam Ratulangi University, Manado, that conducted from August-December 2017. This study used a Complete Randomized Design (RAL), consisting of 8 treatments and each repeated as many 4 times, so we get 32 unit experiment. The variables observed were number of buds, number of leaves, plant height, wet weight, root number and Sulforaphane content analysis. The result of research shows that analysis of variance showed that in the use of Benzyl Amino Purine (BAP) concentration 3 ppm tends to increase the number of leaves aged 4 Weeks After Culture (MSK) and increase the number of shoots age 2 and 6 Weeks After Culture (MSK). Benzyl Amino Purine (BAP) 3 ppm can increase the wet weight of age 6W eeks After Culture ((MSK). Coconut water 20% tends to increase the number of leaves at age 6 Weeks After Culture (MSK) and increase the number of shoots aged 6 Weeks After Culture (MSK), while for combination of 3 ppm Benzyl Amino Purine (BAP) and coconut water 20% tends to increase the number of leaves aged 2 Weeks After Culture (MSK) and the number of shoots aged 2 Weeks After Culture (MSK). Combination of coconut water and Benzyl Amino Purine (BAP) is not detected by the content of Sulforaphane.


2018 ◽  
Vol 5 (1) ◽  
pp. 136-146
Author(s):  
Supriadi Hartanto ◽  
Irsal ◽  
Asil Barus

This research was conducted to determine the growth of red sugarcane seedling on pruning and frequency of watering. This research was conducted in the research field of Faculty of Agriculture University of Sumatera Utara (± 25 m asl) from June-October 2017 using Factorial Randomized Block Design with three replications. The first factor was pruning (control, 1, and 2 months/plant) as well as the second factor was the frequency of watering (1, 3, 5, and 7 days/plants). The variable observed were plant height, a number of leaves, stem diameter, a number of the tiller, shoot wet weight, root wet weight, and shoot-root ratio. The results showed that the frequency of watering treatment had a significant effect on the number of a leaf (4,6,8,10 and 12 weeks after plant), stem diameter (4,6,8,10 and 12 weeks after plant), shoot wet weight, and root wet weight. Pruning treatment had no significant effect on all variables observed. The interaction of both has no significant effect on all variables observed.


2021 ◽  
Vol 2 ◽  
pp. 234-239
Author(s):  
Nada Kholifah ◽  
Ardiana Kartika B ◽  
Teguh Pribadi

PGPR (Plant Growth Promoting Rhizobacteria) is a substance that helps plant growth with the help of rhizosphere microorganisms. PGPR propagation can be done with liquid media. This PGPR propagation needs to be done because this substance has many benefits for agricultural cultivation. The application of PGPR to the test plant, namely the pakcoy plant, proved that there was an effect of giving PGPR to the plant. Observations on the test plants were carried out by observing several observation variables such as plant height, root length, number of leaves, wet weight and dry weight. The results of these observations showed that the effect on the test plants was seen in the variables of root length, wet weight, and dry weight. Meanwhile, the variable plant height and number of leaves did not show a visible difference. 


1969 ◽  
Vol 22 (1) ◽  
pp. 53 ◽  
Author(s):  
D Aspinall

The acceleration of flowering in barley due to the inclusion of incandescent illumination in the light source has been shown to be due to the far�red content of the light. A linear relationship between floral development and intensity of far�red light in a 16�hr photoperiod has been established with the cultivar CI5611. Barley appears to be relatively unresponsive to blue light, however.


Nabatia ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Andy Pradana ◽  
Al Machfudz WDP

This study aims to determine the application of potassium fertilizer and chicken manure to the growth and production of shallots (Allium ascalanicum L.). The study used a randomized block design with 2 factors repeated 3 times. Factor 1: Potassium Fertilizer 40,60,80 kg/ha. Factor 2: Chicken Manure 5,10,15 tons/ha. The results showed that the application of potassium fertilizer and chicken manure did not interact with either the growth phase or the production phase of the plant on all observation variables, while the potassium fertilizer treatment showed significantly different results only on the plant vegetative growth parameters, namely the number of leaves at the age of 7 days after planting, namely ( 8,111 strands), while the vegetative phase had no significant effect on the number of tubers per clump, wet weight of tubers per clump, wet weight of tubers per plot, dry weight of sun-dried tubers per clump, and dry weight of sun-dried tubers per plot. While the treatment of chicken manure had a significant effect on the vegetative growth phase of plants, namely the length of plants at 28 DAP (30.278 cm) and 35 DAP (32.704 cm), on the number of leaves at 7 DAP (8,000 strands). While the generative phase (60 DAP) significantly affected the number of tubers per clump, namely (5,889 grams), wet weight of tubers per clump (38,333 grams), wet weight of tubers per plot (319,000 grams), dry weight of sun-dried tubers per clump. namely (23.074 grams), and the dry weight of sun-dried tubers per plot (191.889 grams).


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