籼稻的抗冷性与亲本的关系

四个籼稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）品种幼苗经１℃黑暗或光照２５０ μｍ ｏｌ·ｍ － ２·ｓ－ １处理后,抗冷的“桂山矮选３”比不抗冷的“青华６ 号”幼苗存活率高,其子代是以“桂山矮选３”为母本的比“青华６ 号”为母本的存活率较高。抽穗期剑叶经光照低温处理１２、２４ 和３６ ｈ 后,光合作用是“桂山矮选３”和以“桂山矮选３”为母本的子代比“青华６ 号”和以“青华６ 号”为母本的子代下降较少。呼吸作用是前者比后者在处理１２ ｈ 时有明显升高现象。荧光参数Ｆｖ／Ｆｏ和Ｆｖ／Ｆｍ比值在处理２４ ｈ 时前者比后者下降明显,但在常温下恢复则是前者比后者明显较快。自然低温（寒露风）对叶绿素荧光的影响亦有相似的规律。对水稻后代的抗冷性倾向于母本进行了讨论     

Genome characterization of glucose-isomerase-producingStreptomyces sp. NCIM 2730: detection of sequences homologous to a rice repeat sequence

Restriction analysis of the genomic DNA from a high glucose/xylose-isomerase-yieldingStreptomyces sp. NCIM 2730 revealed a number of distinct bands on a background smear, indicating the occurrence of repeated DNA sequences in the genome. Optical renaturation analysis indicated that 25% of the genome comprised rapidly reannealing sequences with a copy number of 50 and a kinetic complexity of 3×10³. Hybridization of theStreptomyces genomic library with theStreptomyces DNA, supported the estimate of the repetitive DNA content derived from the re-association kinetics of the DNA. Hybridization of DNA from three differentStreptomyces species with a rice repetitive DNA probe revealed the presence of homologous sequences, which is a unique finding.M.S. Ghatge was and V.V. Deshpande and P.K. Ranjekar are with the Division of Biochemical Sciences, National Chemical Laboratory, Pune -41108, India; M.S. Ghatge is now with the Department of Microbiology & Molecular Biology, The University of Kansas Medical Center, 36th and Rainbow Blvd, Kansas City, Kansas - 66103, USA.     

Distribution of toxigenic Bacillus cereus in rice samples marketed in Hong Kong

Eleven of 16 samples of rice on sale in rice shops and supermarkets in Hong Kong contained Bacillus cereus. Although B. cereus counts did not exceed 100 bacteria/g in most of the positive samples, a sample of Thai red rice and a poor quality rice originating from China contained between 300 to 1000 cells/g and 10⁴ to 2×10⁵ cells/g, respectively. Nine strains produced an enterotoxin responsible for the diarrhoeal-type B. cereus food poisoning and seven of these strains also produced a haemolysin (haemolysin BL), a dermonecrotic vascular permeability factor which may be a virulence determinant in diarrhoeal illness caused by this bacterium.P.K. Lee and J.A. Buswell are with the Department of Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong; K. Shinagawa is with the Department of Veterinary Medicine, Iwate University, Iwate, Japan.     

苯并［a］芘在土壤－水－水稻系统中传输动力学研究

建立了ＢａＰ在土壤水稻系统中传输模型,并对其在系统各组分中的含量变化做了定量分析。实验求得了ＢａＰ在系统各相间传输速度常数和分配系数。揭示了水中ＢａＰ向水稻体传输路径和它们的速度大小。水稻从水中吸收ＢａＰ的速度比其从土壤中吸收的速度高４倍,水中ＢａＰ向土壤沉积速度比水稻从水中吸收ＢａＰ的速度高７倍。水中ＢａＰ在迁移到达水稻体之前,绝大部分被土壤牢牢吸附而很难被水稻吸收。     

Sink anatomy in relation to solute movement in rice (Oryza sativa L.): A summary of findings

The results of studies on assimilate and water transport in the developing caryopsis of rice are summarised. Evidence is presented for a symplastic movement of solutes as far as the aleurone layer. However, transport into the apoplast at the nucellus/aleurone interface appears to be a necessary step due to the absence of plasmodesmata at this site. It is suggested that water leaves the caryopsis during grain filling by the isolated cell walls of the pigment strand, the suberised walls of these cells functioning to isolate the apoplast from the symplast and thereby allowing opposing fluxes of water and assimilates to occur in the dorsal region of the grain.     

Effect of submergence on translocation,starch content and amylolytic activity in deep-water rice

Submergence induces rapid internodal elongation in deep-water rice (Oryza sativa L. cv. Habiganj Aman II). We investigated the metabolic activities which help to support such fast growth. Three days of submergence in water under continuous light led to the mobilization of 65% of the starch from those regions of rice internodes which had been formed prior to submergence. Disappearance of starch was accompanied by a 70-fold enhancement of amylolytic activity. Similar increases in amylolytic activity were detected in response to ethylene and gibberellic acid. Submergence also caused a 26-fold increase in the translocation of newly synthesized photosynthetic assimilates from the leaves to the internodes and younger regions of the culms. These physiological processes are likely to provide the metabolic energy required for internodal elongation in response to submergence.Abbreviation GA₃ gibberellic acid     

Concentration of iron and manganese in rice plants as influenced by hexachlorocyclohexane applied to soil

Summary Application of a granular formulation of hexachlorocyclohexane (HCH) to the potted soil at flooding decreased the concentration of iron and. to some extent, manganese in rice plants, especially at concentrations above 3 ppm active ingredient (a.i.) Likewise, HCH, applied to rice fields at transplanting (several days after submergence) caused a significant decrease in the concentration of iron, and not manganese, in the rice plant but only at concentrations above 12.5 kg a.i./ha despite high levels of reduced iron in the soil. Inhibition of iron reduction by HCH was more pronounced when applied at flooding than at several days after flooding.     

Freeze-preservation of rice cells: A physiological study of freeze-thawed cells

Rice ( Oryza sativa L.) cells returning to in vitro culture after preservation at superlow temperature in liquid nitrogen are characterized by a number of physiological alterations. These include: reduction in respiration and glucose uptake, loss of intracellular potassium, decrease in the cellular level of key metabolites (ATP, glucose-6-phosphate and pyruvate) and fragility of protoplasts following the action of cell wall-degrading enzymes.
Nevertheless, cell growth resumes after a short lag phase (2–4 days) with an actual 70–100% cell survival, thus indicating that the observed damage is not lethal and can be repaired in a short time.     

Effect of drought on proteins and isoenzymes in rice during germination

Two drought tolerant varieties TKM-1 and TKM-2 and two drought susceptible varieties Jaya and Improved Sabarmati of rice were studied for soluble protein pattern and isoenzymes of malate dehydrogenase, glutamate dehydrogenase, esterase and peroxidase during germination at different water stress. MDH, GDH and esterase patterns were not affected, but the soluble proteins were changed. Peroxidase isoenzyme pattern from drought tolerant and susceptible varieties showed characteristic differences. The intensity of bands with higher electrophoretic mobility decreased in Jaya and Improved Sabarmati while in TKM-1 and TKM-2 the intensity of these bands did not change much after 72 hr water stress. In shoots of Jaya and Improved Sabarmati, the activity of the peroxidase isoenzymes decreased more than in TKM-1 and TKM-2 shoots with increase in water stress.     

Properties of a major α-globulin of rice endosperm

Globulin was isolated from milled rice (Oryza sativa, line IR480-5-9) by 5% NACl extraction and was precipitated by (NH₄)₂SO₂ or by dialysis against water. The extract was purified by repeated isoelectric precipitation at pH 4.5. The major globulin fraction (40%) exhibited one band by electrophoresis at pH 4.5 but two bands at pH 8.3. Similarly, one sharp peak was shown by sedimentation corresponding to 1.41S (α-globulin) in acetic acid (pH 2) and NaOH (pH 11.7) but a broad asymmetric peak was obtained at pH 6.7, 8.3 and 8.9. Gel filtration of the α-globulin at pH 6.5 exhibited 2 proteins with MW 20 000 and 98 000. The results suggest a pH dependent aggregation phenomenon. The two proteins could not be separated by DEAE-cellulose chromatography. SDS-polyacrylamide electrophoresis of α-globulin revealed one subunit with MW 18 000. This α-globulin is poorer in lysine and histidine but richer in cystine, methionine, arginine, tyrosine and glutamic acid than whole milled rice proteinfa]Taken part from the M.S. thesis of AAP from the University of the Philippine at Los Baños (1977).