Germination ecology of Leptochloa chinensis: a new weed in the Italian rice agro‐environment

Abstract

Summary Leptochloa chinensis is a new weed that has been found with increasing frequency in Italian rice paddies. The germination ecology of L. chinensis seeds was studied in order to investigate the development mechanisms and survival strategy of this weed in rice paddies of northern Italy. Leptochloa chinensis seeds showed no dormancy and exhibited germination even in anoxic conditions. Germination was strongly influenced by temperature (minimum around 15°C; optimal 25–35°C) and light (phytochrome dependent). Temperature fluctuation caused an increase of seed germination in the dark. Seed burial also strongly inhibited germination and emergence of this species. At 5 cm seed burial only 5% of seedlings emerged in flooded conditions, while at the same depth, but with no flooding, no seedling emergence was observed. This phenomenon was not due to oxygen depletion, as germination was not inhibited by complete anoxia, as demonstrated by the fact that some seedlings did emerge in flooding conditions when water was no deeper than 6 cm. Seed burial and concomitant flooding induced an unusual germination: first coleoptile emergence and subsequently emergence of the radicle was observed. The possible exploitation of this knowledge for weed management is discussed.

Germination Ecology of Chinese Sprangletop (Leptochloa chinensis) in the Philippines

“…This also indicates that the soil seed bank could be depleted by stale seedbed strategies before crop establishment. Similar results of high germination (95%) immediately after seed harvest were reported for an Italian population of Chinese sprangletop (Benvenuti et al 2004).…”

“…Flooding had a major suppressive effect on the emergence and dry matter of Chinese sprangletop. It is useful to mention here that germination and emergence responses to some factors (e.g., light and seed burial depth) were different between our study and the study conducted with seeds of the Italian population (Benvenuti et al 2004). This suggests that Chinese sprangletop could be polymorphic in its response to light and burial depth, and further studies are required to elucidate this.…”

“…It is a common weed in direct-seeded rice fields (Chin 2001) and is reported to occur in 16 countries in dry-seeded rice and in seven countries in wetseeded rice (Rao et al 2007). Chinese sprangletop has recently been reported as a new weed in Italy with increasing frequencies in rice fields (Benvenuti et al 2004).…”

“…Knowledge of weed seedling emergence in relation to soil depth is important for the application of soil herbicides to control the emerging weed seedlings. Some information on the germination ecology of Chinese sprangletop is available on an Italian population (Benvenuti et al 2004). Light stimulated germination, but some seeds germinated in the dark as well.…”

Tolerance and recovery responses of playa halophytes to light, salinity and temperature stresses during seed germination

“…Absence of light inhibits the seed germination either completely (Benvenuti et al, 2004), or partially (Zia and Khan, 2004), or may have no effect (Wei et al, 2008;Zheng et al, 2005). The interaction of light, temperature and soil moisture is also reported previously as a controlling factor for dormancy where seed germination was inhibited at extreme salinity or/and temperature regimes more in the absence of light (Baskin and Baskin, 2004;Benech-Arnold et al, 2000;Vleeshouwers et al, 1995).…”