Development of rice seedlings grown from pre-hydrated seeds and irradiated with gamma rays

Abstract

Techniques used to induce mutations, such as ionizing radiation, are an effective tool in increasing genetic variability in breeding programs of species of economic interest. This study aimed to evaluate the effect of different doses of Co60 gamma radiation on previously soaked seeds on the emergence and early growth of seedlings of two rice cultivars. To do this, seeds (25% moisture) of BRS Querência and BRS Fronteira were irradiated with zero (control), 50, 100, 150 and 200 Gy, and then sown in trays containing soil and kept in a greenhouse. The results showed that gamma radiation affected seedling development, where the highest dose tested (200 Gy) significantly reduced the emergence and the index of emergence speed. Growth parameters were reduced greater reduction in cv. BRS Querência. For antioxidant enzymes, superoxide dismutase expressed little variation for the periods evaluated. Already ascorbate peroxidase and catalase showed a significant increase in horsepower cv. BRS Fronteira at 14 DAS, followed by an increase in both cultivars ascorbate peroxidase activity at 28 DAS. The highest antioxidant capacity observed in cv. BRS Fronteira conferred greater tolerance to stress caused by gamma radiation.

Morphophysiological and biochemical alterations in Ricinus communis L. seeds submitted to cobalt60 gamma radiation

“…The ESI presented showed a response similar to that of emergence at 200 Gy; at this dose, a significant decrease in ESI was noted in relation to the control group and the 50 and 100 Gy treatments, illustrating the negative effect of this radiation dose on seedlings (Figure 2b). Similar results were observed in two rice cultivars (Silva et al 2011). Thus, the decrease in germination may be related to the radiosensitivity of the embryonic axis, but the damage can occur in any part of the seed.…”

“…Although there was no significant difference in emergence in the intermediate doses (50, 100, and 150 Gy) when compared to the control group, but a decreasing trend was observed (Figure 2a). Previously, gamma radiation was found to reduce seedling emergence in wheat (Grover and Khan 2014), rice (Pons et al 2001, Silva et al 2011, and sesame (Sesamum indicum L.) (Boureima et al 2009). Seeds that were not irradiated showed better germination and there was a reduction in emergence as the Co 60 gamma radiation dose increased.…”

“…Bars represent the standard error of the mean of four replications. beans (Kon et al 2007), rice (Silva et al 2011), and wheat (Grover and Khan 2014). This decrease in growth may be attributed to a reduction in mitotic activity in meristematic tissues and a decrease in seed humidity (El-Sherif et al 2011).…”

“…These photons have a high penetrating power and can interact indirectly with matter, causing ionization and excitation. Previous studies in plants have reported modifications of growth and development, a decrease in reproduction capacity, metabolic alterations and DNA damage under radiation stress (Vanhoudt et al 2010, Silva et al 2011). In addition, gamma radiation, for example, through the radiolysis of water can result in the formation of reactive oxygen species (ROS) which on their turn potentially lead to cellular damage (Esnault et al 2010).…”

Rice mutants and their responses to suboptimal temperatures in the early stages of development

“…The choice of these genotypes was based on characters of agronomic interest that are superior to those of their cvs. of origin, previously assessed by Silva et al (2011) and Silva (2013), such as cycle reduction and reduction in the number of sterile spikelets and the height of plants, as well as increased amount of grains per panicle and 1000-grain weight. The seeds were harvested in 2012/2013 and selected based on size uniformity and absence of spots.…”