澳洲坚果落果种子萌发力研究

澳洲坚果种子鲜播 17～ 2 0d后开始萌发 ,2 5～ 35d进入萌发高峰期 ,播后 60d尚有少数种子萌发 ,85d后种子不再萌发 ,不同品种的种子发芽率有差异。不同收获期的种子发芽率不同 ,品种 2 4 6在 6月下旬以后的落果种子有 60 %的发芽率 ,7月 2 6日的落果种子发芽率高达 84% ,此期种子可用来播种育苗。化学药剂对近成熟的澳洲坚果种子萌发有影响 ,以 2 0 μg mL的赤霉素和 80 μg

成熟度对诺丹冰草种子质量的影响

本文从种子萌发力、水分变化、百粒重变化等方面对成熟度与种子质量的关系进行分析。结果表明,诺丹冰草种子随着成熟度的提高,生活力逐渐增加,种子含水量不断下降,百粒重不断增大。同时对种子进行加速老化处理,结果表明老化处理后在15d～30d内收获的种子发芽率明显降低,而35d～40d收获的种子变化不明显,表明此阶段种子的活力已达到较高的水平。诺丹冰草种子最佳采收期的种子含水率约在20%～25%之间。

Allelopathic Potentials of Some Crop Residues on the Germination and Growth of Bidens pilosa. L.

The allelopathic potentials of the aqueous extracts of rice husk and sorghum stem were examined on the germination and growth ofBidens pilosa. L. The extracts inhibited the germination ofB. pilosa seeds and the growth lengths of its radicle and plumule. In both extracts, the severity of the inhibition increased with the increase in the concentrations of the extracts, indicating that the effects of the extracts were concentration dependent. The results obtained also showed that the degree of retardation appeared to be more pronounced in the rice husks extract-treated seeds than those of sorghum extract-treated seeds. However there were no significant differences （at 5% level） in the comparison of the degree of inhibitions of radicle and plumule growths at the varying extract concentrations as well as those of the control in both extracts treated seeds.

Imbibitions, energy test and accelerated ageing in primed and non-primed seeds of Peltophorum dubium

Peltophorum dubium seeds were set to imbibe with four treatments, soaked with solution Captan 0.2% under 10and 27℃,PEG 6000 -1.0 MPa under 10 and 27℃. For each treatment there were four replicates with 40 seeds incubated in 9-cm Petri dishes with double filter paper moistened with testing solution. The imbibition curves showed that the final weight increase were from 70% to 150% in the treatments when imbibition entered a lag phase. Seeds were tested for effects on germination of five treatments: control group (nonprimed), primed with PEG6000 -1.0 MPa at 10 and 27℃, primed with Captan 0.2% at 10 and 27℃. For each treatment, there were three sub-treatments: seeds were soaked in distilled water for 12, 24 and 36h before the energy test. Germination percentages of nonprimed seeds and primed in PEG 27℃ soaked in distilled water during 12 h were the highest, reaching 100%. The lowest germination percentage occurred primed seeds with PEG6000 27℃ and soaked in distilled water during 36 h, which was only 52%. Germination mean time of primed seeds in PEG at 10℃, soaked 24 h was 1.08 days, mean time of primed seeds in PEG at 27℃ soaked 12 h was 2.42 days. Accelerated ageing results showed low or no germination after ageing 72 h. Control group had a higher germination percentage and seeds were more resistant to deterioration than those in primed groups, both in Petri dish (27℃) and vermiculate (room temperature).

Study on Cadmium Tolerance Differences of Seed Germination and Seedlings in Different Varieties of Maize

To ascertain the genotypic difference of cadmium tolerance of different varieties of maize, effects of cadmium stress on the germination rate, germination index, vigor index, root length and fresh weight, and shoot length and fresh weight of seeds of 12 main varieties of maize widely cultivated in central Hunan were studied. The results showed that the cadmium stress had small impact on the germination rate and germination index of maize seeds, but it had obvious effects on the vigor index, root and shoot growth of maize seeds, and the inhibition effects on the roots were more obvious than the shoots. Among the 12 varieties of maize, Qiandan 12, Dushiliren, Nuobatianxia and Nongda 3138 were tolerant to cadmium stress, while Tianguan 218 was sensitive to cadmium stress, and the tolerance of other varieties of maize to cadmium stress was moderate.

Allelopathic Potential of Some Crop Residues on the Germination and Growth of Soybean （Glycine max L,） Merrill

Allelopathic potentials of aqueous water extracts from residues of sorghum stem, maize inflorescence and rice husks on the germination of soybeans （Glycine max. L.） were investigated. The result showed that the extracts brought about a considerable inhibition in the germination of soybean seeds, reductions in the radicle and plumule lengths of soybean seedlings. Whereas, the extracts of maize inflorescence and rice husk had more inhibitory effects on the growth of soybean radicle, all the three extracts demonstrated pronounced inhibitory effects on the growth of the plumule. The retardation of soybean germination, radicle and plumule growths were concentration dependents as the degree of retardations increases with increase in the concentration of the extracts. Statistical analysis （ANOVA, P = 0.05） revealed that there were no significant differences in the germination, radicle and plumule growths at 24 and 48 h experimental time when compared to the control. However, statistical differences abound in the growth parameters at 72 and 144 h experimental time.

Allelopathic Effect of Achillea （Achillea santolina） on Germination and Growth of Crop Plants

In order to investigate the likely allelopathic potential of an aqueous extract and powder of Achillea （,4chillea santolina） on the germination and seedling growth of pea （Cicer arietinum）, safflower （Carthamus tinctorius L.） and wheat （Triticum sativum）, an experiment was carried out at the laboratory and greenhouse of agriculture faculty of Sho3hid Bahonar University of Kerman, Iran, from October 2009 to March 2010. A completely randomized design with three replicates using five extract concentrations of achillea plant including 0, 25, 50, 75, and 100 g Ll and four amounts of powder of it including 0, 7.5, 15 and 30 g kg1 of soil was employed in laboratory and greenhouse experiments, respectively. All extract concentrations of achillea except 25 g Ll inhibited pea and wheat seed germination significantly, but had no inhibitory effect on the germination of safflower, The powder of mature achillea plants affected the fresh and dry weight and shoots length in these crops negatively compared with the control in all levels. Therefore use of this plant should be prevented in rotation or intercropping with these three crop plants. Further research conducted in the analytical laboratory as well as in the field is needed before a practical application of the extract and powder as weed inhibiting agent can be recommended.