Plant Movement and Seed Dispersal of Russian Thistle (Salsola iberica)

Abstract

Russian thistle plant movement and seed dispersal were studied in 1991 and 1992 by placing Russian thistle plants in the center of wheat fields in eastern Washington. Three adjacent site treatments, with 24 plants on each site, were used each year; wheat stubble, summerfallow planted to winter wheat, and a “stationary” site. Plants in the “stationary” site were anchored to the ground to prevent tumbling. Plants in the stubble and summerfallow sites were allowed to tumble naturally. Individual plant movement was monitored and recorded weekly by satellite global positioning systems technology. Average estimated seed number per plant at the beginning of the experiment was 57,400 in 1991 and 66,000 in 1992. The direction plants moved correlated highly with wind direction. Some plants moved a maximum distance of 4069 m in 6 wks, while other plants moved only 60 m because of variable winds and being compressed by snow or frozen into wheat stubble. Average percentage seed loss in 1991 and 1992 for stationary plants was 15 and 26%, and for tumbling plants was 48 and 66%, respectively.

Identification of glyphosate resistance in Salsola tragus in north‐eastern Oregon

“…Salsola tragus plants are characterized by high seed production, i.e. over 50 000 seeds per plant, and the ability to spread seed widely due to tumbling at plant maturity …”

Tumbleweeds in the Western Australian cropping system: seed dispersal characteristics of Salsola australis

“…This indicates that S. australis plants moved and shed seed in a manner similar to that for S. iberica or S. kali (Young, 1991; Mallory‐Smith et al. , 1993; Stallings et al. , 1995).…”

“…Species of the Salsola genus that are agricultural weeds are often early successional species that engage in broad scale seed dispersal (Schmidt & Reeves, 1989; Mallory‐Smith et al. , 1993; Stallings et al. , 1995).…”

“…Movement of Salsola iberica (Sennen and Pau) Botschantzev ex Czerepanov in Washington State (Mallory‐Smith et al. , 1993; Stallings et al. , 1995) and Salsola kali L. in Idaho (Warren, 2001) was influenced by climate (mainly wind speed and direction), vegetation type, geography and artificial obstructions.…”

Weeds Resistant to Nontriazine Classes of Herbicides

“…Since resistance to ALS inhibitors can be spread both by seed and pollen, once the initial incident of resistance occurs, the resistant subpopulation will dominate the population in a very short period of time. Stallings et al (1995a) studied the Russian thistle plant movement and seed dispersal in order to follow the spread of chlorsulfuron-resistant biotypes. They found that 48% to 68% of the Russian thistle seed were lost as the plants tumbled across the fields, and they were carried by varying winds from 60m to more than 4 km.…”