[Physiological responses and tolerance to drought stress of different watermelon genotypes.] / ä¸åŒè¥¿ç“œåŸºå› åž‹å¯¹å¹²æ—±èƒè¿«çš„ç”Ÿç†å“åº”åŠå ¶æŠ—æ—±æ€§è¯„ä»·.

With the continuous drought stress treatment to 12 pot-grown watermelon genotypes originated from different regions, the influence of drought stress on plant height, root length, fresh mass and dry mass was studied, and the physiological responses of these genotypes to drought stress were compared. Drought resistance of these watermelon genotypes was preliminarily determined according to the drought injury, and then confirmed by membership function evaluation method. We found that the watermelon genotypes exhibited great difference in drought tolerance based on the occurrence of drought injury and the degree of injury severity. Drought stress reduced plant height, shoot- and root- fresh mass as well as shoot- and root- dry mass, while increased the root/shoot ratio for most genotypes; but for root length and root dry mass, it had both positive and negative effects depending on the tested genotype. Compared with the control, all drought-treated watermelon genotypes exhibited a decline in leaf relative water content and chlorophyll content, as well as increases in MDA, H2O2, O2-· and proline contents. Different watermelon genotypes displayed diversity in soluble protein content and antioxidant enzyme activity. Our results showed that three wild watermelon genotypes including M20, Y-2, and KY-3 were drought tolerant while Y34, 04-1-2 and Golden Girl were drought sensitive, and the rest genotypes were among the medium.

[Study on treatment of iron-deficiency anemia by shengxuening].

OBJECTIVE: To observe the therapeutic effect of shengxuening (SXN) in treating iron-deficiency anemia (IDA) and to explore its molecular mechanism on iron metabolism balance regulation. METHODS: Patients with IDA were randomly divided into the treated group and the control group, 50 in each group. They were treated with SXN (0.1 g, three times per day) and ferrous gluconate (0.1 g, three times per day) respectively, for 30 days. Levels of serum iron (Fe), total iron binding capacity (TIBC), transferrin saturation (TS), serum ferritin (SF), transferrin (Tf), soluble transferrin receptor (sTfR) and blood routine test, as well as scoring of TCM qi-blood deficiency Syndrome were conducted before and after treatment. RESULTS: The total effective rate in the treated group reached 92%, it was shown that SXN could improve the iron metabolism, increase levels of Fe, TS, SF and reduce levels of TIBC, Tf, sTfR, it has obvious effect in promoting erythrocyte generation and could promote formation of leucocytes and platelets. The total effective rate in the control group was 32%, which was significantly lower than that in the treated group (P < 0.01). CONCLUSION: The effect of SXN in treating IDA and qi-blood deficiency Syndrome is evident, it could improve the iron metabolism, increase levels of Fe, TS, SF and lower levels of TIBC, Tf, sTfR.

[Effects of soil compaction stress on respiratory metabolism of cucumber root].

A pot experiment with cucumber cultivar "Jingchun 4" was conducted to study the effects of soil compaction stress on the respiratory metabolism of cucumber root. Two treatments were installed, i.e. , soil bulk densities 1.20 and 1.55 g . cm-3. Under soil compaction stress, the activities of root pyruvate decarboxylase, alcohol dehydrogenase, and lactate dehydrogenase and the contents of root anaerobic respiration products alcohol, acetaldehyde, and lactate increased significantly, while the activities of the key enzymes involved in root aerobic respiration, including malate dehydrogenase, succinate dehydrogenase, and isocitrate dehydrogenase, decreased significantly, root pyruvate and succinate contents had significant increase, whereas root malate content decreased significantly. All the results illustrated that under soil compaction stress, the aerobic respiration of cucumber root was inhibited, while its anaerobic respiration was promoted.

[Effects of soil compaction stress on the growth and nitrogen metabolism of cucumber roots].

Taking cucumber cultivar 'Jinchun 4' as test material, a pot experiment was conducted to study the effects of soil compaction stress on cucumber root growth, respiration rate, activity, and nitrogen metabolism at different development stages. Two treatment were installed, i. e., bulk density 1.25 g x cm(-3) (loose soil, CK) and 1.55 g x cm(-3) (compacted soil). Under the stress of soil compaction, the total root length, root surface area, root forks, and root tips at different development stages decreased significantly, the root elongation growth and lateral root emergence were constrained remarkably, but the root radial growth was stimulated and the root average diameter was significantly increased. Meanwhile, both the root activity and the respiration rate decreased significantly, the root NO3(-), free amino acids, and soluble protein contents had a large decrease, the root nitrate reductase, glutamine synthetase, and glutamate synthase activities decreased significantly, whereas the root NH4(+) content had a significant increase. All the results indicated that under the stress of soil compaction, the uptake of nitrate by cucumber roots decreased, the nitrogen assimilation was inhibited, and the nitrogen metabolism was remarkably constrained.