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Abstract
Observation of vegetation injury induced by exposure to air pollutants provides a simple and low cost means of monitoring pollutant emissions from a particular source as well as for determining the distribution of pollutants over a wide area. This use of plants has long been accepted and has been extensively reported (2, 7, 8, 14). However, many other environmental factors may also cause plant injury and their effects are often difficult to distinguish from pollution-induced damage (13). In addition, factors such as temperature, humidity, wind velocity, light, nutrition, water supply, and the presence of pesticides and other chemicals have all been shown to markedly influence plant sensitivity to air pollutants.
Abstract
The effects of 4 air and soil temperature regimes on plant growth and pea yield responses to applied P were investigated in controlled environments. The plants were grown in a low-P (4 ppm) Monroe silt loam, and harvested at 4 predefined stages of plant development. At the 6th node stage applied P increased vine (leaf and stem) weight only at the 21°/13°/18°C day/night/soil temperature regime. At the 10th node and full bloom stages P increased vine weight at all temperature regimes. Increases due to P were greater at the high soil temperature of 18° than at 10°. The increase due to P at the high soil temperature was greater at the cool air temperature of 21°/13° than at 30°/21°. At estimated marketable maturity of peas, P increased the dry weights of the root, vine, pod and pea seed at all temperature regimes, but the magnitude of such increases depended on the tissue and the temperature regime. Efficiency of P in promoting pea yield was greater at the high soil temperature, particularly at cool air temperature. The nearest optimum temperatures were a day/night air temperature of 21°/13° and a soil temperature of 18°. The nearest optimum P rate was 50 kg/ha.
Abstract
The effects of 4 air and soil temperature regimes and 3 levels of P on the concentrations and total contents of N, P, K, Ca and Mg in pea plant tissues were investigated in controlled environments. There were generally no significant interaction effects between temperature regimes and applied P when contents of these minerals were expressed as per cent of dry matter. When contents were expressed as total uptake into the various tissues there were significant interactions for all 5 minerals.
At the pre-fruiting growth stages, tissue concentration of P generally increased with applied P, particularly at the highest rate. P concentration responses at the 10th node stage were similar to those at the 6th node, but there was a reversal of these effects at full bloom. The warm air temperature of 30°/21°C (day/night) generally increased P concentration but depressed total uptake compared with a temperature of 21°/13°. The increases were largely due to concentration effects resulting from smaller plants. Increases in P concentration at the high soil temperature of 18°, compared with 10°, were absolute because they occurred regardless of plant size. Applied P increased the total uptake of minerals as well as their translocation into the seed.
Abstract
Atmospheric pollutants cause decreased yields, growth suppression and low product quality in both ornamental and vegetable crops, including petunias (23), begonias (45), snapdragons (1), onions (21), beans (70), cucumbers (53), radish (49), tomato (55) and several others (32). Fruit crops most widely injured are grapes (59) and citrus (69). Details of other sensitive plants have been discussed by Rich (57).
Abstract
In field trials at two locations in British Columbia, dimethyl sulfoxide applied as a 5% foliar spray, increased the yield of ‘Dark Skin’ Perfection’ peas by 11.5 and 25.3%. The foliar application of Cycocel at 50 ppm increased yield by 14.6 and 17.4%. The effects of DMSO and Cycocel were additive, there being no interaction.
Abstract
In 2 greenhouse experiments, 15-day old pea seedlings were sprayed with 1 or 100 ppm of Cycocel, Phosfon or B-Nine. The plants were grown to marketable maturity of peas.
Cycocel at 1 ppm increased plant height, internode length, pea yield and total dry matter, but decreased chlorophyll concentration as well as the ratio of chlorophyll a:b. Cycocel at 100 ppm decreased plant height, internode length and total dry matter, but had no significant effect on pea yield. Phosfon at 1 ppm had little effect on growth and yield, but 100 ppm markedly decreased plant height and pea yield while increasing chlorophyll concentration. B-Nine at both concentrations was relatively ineffective in altering the growth pattern of the pea plant.
Cycocel generally increased the concentrations of N, P and Mg in the pea vine. Phosfon generally increased P and Ca. B-Nine at 1 ppm decreased N and P while it increased both at 100 ppm. All 3 compounds generally decreased K.
Abstract
No appreciable signs of phytotoxicity were observed for 4 days following fumigation of plants (including begonias, petunias, snapdragons) with ozone of up to 80 parts per hundred million (pphm) or sulfur dioxide of up to 400 pphm for 2 hr. Thereafter, there was considerable necrosis, particularly on begonias fumigated with the highest concn of the pollutants. Growth suppression was reflected in reduced shoot and flower wt, and to a lesser degree in reduced flower number. Overall, begonias and petunias were the most sensitive. Coleus and snapdragons were moderately sensitive, while marigold, celosia, impatiens and salvia were tolerant. ‘White Tausendschon’ was the most sensitive begonia cultivar while blue-flowered ‘Capri’ was the most sensitive petunia. Mixed color petunias exhibited varying degrees of tolerance. ‘Scarlet Rainbow’ coleus was more sensitive than ‘Pastel Rainbow’. Measurements of growth alterations in plants were found very useful in determining latent forms of air pollutant injury.