Can the Giberella zeae toxin zearalenone affect the photosynthetic productivity and increase yield formation in spring wheat and soybean plants?

Abstract

The seeds of soybean cv. Aldana and spring wheat cv. Torka were soaked for 24 h in solution of zearalenone [ZEN, 2,4-dihydroxy-6-(10-hydroxy-6-oxo-trans-1-undecenyl)-benzonic acid lactone, 4 mg dm -3 ] and then they were sown in the pot experiment in an open vegetation hall. The after-effects of ZEN on growth of plants, net photosynthetic (P N ) and transpiration (E) rates, stomatal conductance (g s ), photochemical efficiency of photosystem II (PSII) and on final seeds yield, were determined. A significant increase of seeds yield was revealed in plants of both cultivars i.e. by 22% and 19% of seed (grain) number and by 28 and 24% of seed (grain) mass, in soybean and in wheat, respectively. The photosynthetic rate (P N ) was stimulated during the juvenile and final phase by about 13.6% (average) in soybean plants. During other developmental stages, assimilation of CO 2 was retarded. The response of CO 2 assimilation in wheat plants was less pronounced as compared to that in soybean, but an increase of P N by over 24% near the final stage of development was observed. The quantum yield of PSII electron transport (Φ PSII ) in soybean plants was changed after the treatment of seeds by ZEN similarly as for the rate of CO 2 , whereas in wheat it continued to gradually increase i.e. during the whole growth period. Changes of Φ PSII both in soybean and in wheat plants, as the response to ZEN treatment, were accompanied with an increase in the efficiency of changes occurring within the antenna (F v '/F m ') as well as within centres of photochemical reactions (q p ). The conclusion is that ZEN can affect plant growth and development in many ways, as well as in the status and functioning of the photosynthetical apparatus. Some of the effects can be very longlasting, as e.g. stimulation of production of seed yield in response to treatment of seeds with this substance.

The effect of zearalenone on PSII photochemical activity and growth in wheat and soybean under salt (NaCl) stress

“…The increase in photochemical activity of PSII in soybean seedlings after soaking of seeds in ZEN solutions (Table 3) proved similar to that in leaf discs incubated in ZEN solutions. These results are consistent with the earlier observations (Kościelniak et al 2009) that ZEN treatment of plants was the resulted increase in photochemical activity of PSII at the early developmental stages in soybean. ZEN inhibited photochemical reactions in wheat discs, but did not affect PSII activity in wheat seedlings.…”

“…Studies revealed that ZEN induces reactions at many levels of animal cell organization (Hassen et al 2007). It was revealed that ZEN can be also toxic for plants causing chromosome damages and disorders in the synthesis of photosynthetic pigments (Kumar and Sinha 1995) as well as in photosynthesis and growth processes (Kościelniak et al 2009). On the other hand, it was found that ZEN was an endogenous regulator controlling plant development (Meng et al 1992), but as yet the mechanism of its action has not been explained.…”

“…ZEN can increase the number of ears, pods and seeds in wheat and soybean (Biesaga-Kościelniak et al 2006a, b). It can also affect plant growth and development in many ways, as well as in the status and functioning of the photosynthetic apparatus (Kościelniak et al 2009). The response of the photosynthesis process to ZEN and the participation of ZEN in the response of plants to environmental stress are less known.…”

The Interaction Effect of Drought and Exogenous Application of Zearalenone on the Physiological, Biochemical Parameters and Yield of Legumes

“…In drought conditions, ZEN reduced absorbed energy flux (ABS) and trapped energy flux (TRo) for single PSII reaction centers (RCs) while maintaining the level of the electron transport per active reaction center (ETo/RC) at the level of control plants. This demonstrates the more efficient use of energy for photochemical processes in drought stress in plants treated Koscielniak et al (2009) showed that pre-sowing soaking of soybean and wheat seeds in ZEN solution caused a higher PSII efficiency under salt stress and, as a result, an increase in their yield. However, scarce data available in the literature indicate that the stimulation of the photosynthetic process by ZEN probably does not occur in all species.…”