Fumigation Of Seedlings Research Articles

The phytohormone methyl jasmonate as an activator of induced resistance against the necrotroph Alternaria porri f. sp. solani in tomato plants

Exogenous application of 0.1 mM methyl jasmonate (MeJA) throughout seed soaking or fumigation of seedlings could induce resistance against the necrotrophic fungus Alternaria porri f. sp. solani in tomato. MeJA applied at 0.01, 0.1, and 1 mM was found to reduce spore germination and mycelial growth in vitro. This compound at 0.01 and 0.1 mM did not cause toxic responses in the tomato plants; however, ethylene production by seedlings was observed to increase after using of all concentrations. A significant increase in the levels of defense markers such as total phenolics, anthocyanins, and phenylalanine ammonia-lyase activity, in response to exogenous MeJA, was observed. Pretreatment of tomato by soaking the seeds in MeJA or treating them with gaseous MeJA efficiently reduced the development of disease caused by Alternaria only when MeJA was applied at 0.1 mM concentration. Seed priming is an easier method of resistance induction than exposure to gaseous MeJA.

Effects of vanadium, nickel and sulphur dioxide on polar lipid biosynthesis in jack pine

Biosynthesis of polar lipids (phospho- and glycolipids) from [1- 14C]acetate was observed in mature needles from hydroponically grown jack pine seedlings. Treatment of the seedlings with vanadium (V) or nickel (Ni) produced marked concentration-dependent inhibitions in the biosynthesis of all polar lipids. Nickel appeared to be more inhibitory than V at 10 ppm. Fumigation of seedlings with gaseous SO 2 (0.34 ppm) also resulted in reduced biosynthesis of polar lipids. Combined treatment of plant seedlings with metal (V or Ni) and SO 2 produced inhibitory effects that were very similar to those produced by metal alone; however, SO 2 did produce an additive inhibitory effect at 10 ppm V.

Peroxidase Activity as an Indicator of SO2 Injury in Jack Pine and White Birch

Summary Peroxidase (EC 1.11.1.7) activity in jack pine (Pinus banksiana) and white birch (Betula papyri fera) seedlings increased greatly during aging of the foliar tissues. Fumigation of seedlings with SO, caused a marked increase in enzyme activity and sulphur content of both species; these responses were, however, more pronounced in white birch than in jack pine. The stimulation of peroxidase in SO, -fumigated jack pine seedlings appeared to be due to increased production of the peroxidase isoenzymes rather than their activation. Increase in both peroxidase activity and sulphur content in the fumigated needle tissues appeared to be transitory in nature as shown by their decline during recovery in an SO2 free atmosphere. A possible role of peroxidase in SO2-initiated free radical process is discussed.