Agriculture and fishing are the primary source of almost all our food, as well as of many other products, so remain vital activities even though their share in the economy is small and in continuous decline. Partly for this reason public policy in these areas is almost entirely integrated at European level in the Common Agricultural Policy (CAP) and Common Fisheries Policy (CFP). Forestry policies are also heavily affected by EU-level decision-making. As agriculture dominates in terms of direct contribution to GDP and numbers of people engaged in it, as well as accounting for the largest amount of public support expenditure, it is agriculture that will receive the greatest attention here.

Agriculture, Forestry and Fisheries

Inoculation with Pseudomonas spp. Containing ACC-Deaminase Partially Eliminates the Effects of Drought Stress on Growth, Yield, and Ripening of Pea (Pisum sativum L.)

The effects of salt and drought stresses at the water potentials of -2, -4, -6 and -8 bars induced by NaCl and PEG 6000 (polyethylene glycol 6000) each, on germination and early seedling growth, were investigated for 3 pea cultivars (Bolero, Sprinter and Utrillo). Electrical conductivity (EC) values of the NaCl solutions were 4.5, 8.8, 12.7 and 16.3 dS m-1. Germination percentage, mean germination time, root and shoot length, and seedling fresh and dry weight were measured in the study. The objective was to determine genotypic differences among pea cultivars in terms of salt and drought stress and to determine factors (salt toxicity or osmotic stress due to PEG) inhibiting seed germination. The germination results revealed that the genotypes significantly differed for salt and drought stress. Bolero appeared to be more tolerant to salt stress, but Sprinter cv. gave higher values under drought stress. Both NaCl and PEG inhibited germination and seedling growth in all cultivars, but the effects of NaCl compared to PEG were less on germination and seedling growth. All cultivars were able to germinate at all NaCl levels without a significant decrease in germination, while a drastic decrease in germination was recorded at -6 bars of PEG. It was concluded that inhibition in germination at equivalent water potentials of NaCl and PEG was mainly due to an osmotic effect rather than salt toxicity.

/pdf/effects-of-salt-and-drought-stresses-on-germination-and-31k7g30vno.pdf

Effects of Salt and Drought Stresses on Germination and Seedling Growth of Pea (Pisum sativum L.)

A series of experiments were conducted to assess the effectiveness of rhizobacteria containing 1-aminocyclopropane- 1-carboxylate (ACC) deaminase for growth promotion of peas under drought conditions. Ten rhizobacteria isolated from the rhizosphere of different crops (peas, wheat, and maize) were screened for their growth promoting ability in peas under axenic condition. Three rhizobacterial isolates, Pseudomonas fluorescens biotype G (ACC-5), P. fluorescens (ACC-14), and P. putida biotype A (Q-7), were selected for pot trial on the basis of their source, ACC deaminase activity, root colonization, and growth promoting activity under axenic conditions. Inoculated and uninoculated (control) seeds of pea cultivar 2000 were sown in pots (4 seeds/pot) at different soil moisture levels (25, 50, 75, and 100% of field capacity). Results revealed that decreasing the soil moisture levels from 100 to 25% of field capacity significantly decreased the growth of peas. However, inoculation of peas with rhizobacteria containing ACC deaminase significantly decreased the "drought stress imposed effects" on growth of peas, although with variable efficacy at different moisture levels. At the lowest soil moisture level (25% field capacity), rhizobacterial isolate Pseudomonas fluorescens biotype G (ACC-5) was found to be more promising compared with the other isolates, as it caused maximum increases in fresh weight, dry weight, root length, shoot length, number of leaves per plant, and water use efficiency on fresh and dry weight basis (45, 150, 92, 45, 140, 46, and 147%, respectively) compared with respective uninoculated controls. It is highly likely that rhizobacteria containing ACC deaminase might have decreased the drought-stress induced ethylene in inoculated plants, which resulted in better growth of plants even at low moisture levels. Therefore, inoculation with rhizobacteria containing ACC deaminase could be helpful in eliminating the inhibitory effects of drought stress on the growth of peas.

https://www.koreascience.or.kr:443/article/JAKO200822179194535.pdf

D.R. Wilson

Papers

12 – models of growth and water use of field peas (pisum sativum l.)