Effect and Mechanism of Cold Tolerant Seed-Coating Agents on the Cold Tolerance of Early Indica Rice Seedlings

To better understand the effect and mechanism of cold tolerant seed-coating agents on the cold tolerance of rice seedlings, the physiological and biochemical effects of four cold tolerant seed-coating agents （HET, YKJ, YKZYJ, and the ABA seed coating agents） on two early indica rice varieties were studied under chilling stress. The results showed that the rice seedlings treated with cold tolerant seed-coating agents under chilling stress maintained dramatically higher root vigor, POD, CAT and SOD activities, and chlorophyll content, had lower MDA content and electrolyte leakage, and accumulated more soluble sugar and free proline, when compared with the control without the treatment, and finally showed lower plant injury rate. It was indicated that the cold tolerant seed coating agent improved the ability of rice seedlings in resisting to chilling stress. YKZYJ was ranked the first in terms of the efficiency in cold tolerance among the four cold tolerant seed-coating agents tested.

Effect of variety and seed dressing on emergence of high-oleic peanut under low temperature and high soil humidity conditions

Low temperature coupled with high soil moisture during sowing to emergence generally results in poor peanut stand,thereby posing a non-negligible threat to peanut production in north and northeast China.Five high-oleic(HO)peanut cultivars and 4 seed dressing treatments capable of controlling several diseases and insect pests along with untreated checks were used to find the best combinations to cope with the dual stresses during sowing to emergence period.High broad-sense hereditability estimates of seedling emergence indicated great potential for genetic improvement of this trait.Analysis of variance in the split-plot experiment showed that the main effects of variety and seed dressing and their interaction on seedling emergence were significant.Seed dressing treatments increased seedling emergence percentage by 2.09–35.00 percent points.Four of the 5 HO peanut cultivars yielded satisfactory results.For Huayu 665,Huayu 668 and Huayu 965,Huweisanbao may be the best option;for Huayu 962,Weilidan was highly acceptable.These combinations will be evaluated further in multiple environments before large-scale extension.

Regulation of Root-Knot Nematode Behavior by Seed-Coat Mucilage-Derived Attractants

Seed exudates influence the behavior of soil organisms,but howthis occurs remains unclear,particularly for multicellular animals.Here we show that compounds associated with Arabidopsis seed-coat mucilage regulate the behavior of soil-borne animals,specifically root-knot nematodes (RKNs).Infective RKN J2 larvae actively travel toward Arabidopsis seeds through chemotaxis.Analysis of Arabidopsis mucilage mutants demonstrated that the attraction of RKNs toArabidopsis seeds requires the synthesis and extrusion of.seed-coat mucilage.Extracted mucilage alone is not sufficient to attract RKNs,but seed-surface carbohydrates and proteins are required for this process.These findings suggest that the RKN chemoattractant is synthesized de novo upon mucilage extrusion but may be highly unstable.RKNs attracted by thismucilage-dependent mechanism can infect the emerging seedling.However,the attraction signal from seedling roots likely acts independently of the seed-coat signal and may mask the attraction to seed-coat mucilage after germination.Multiple RKN species are attracted byArabidopsis seeds,suggesting that this mechanism is conserved in RKNs.These findings indicate that seed exudate can regulate the behavior of multicellular animals and highlight the potential roles of seed-coat mucilage in biotic interactions with soil microorganisms.