水稻蜡质基因5＇上游区缺失对基因表达的影响

为研究水稻蜡质基因（ｗａｘｙ）５＇上游调控区中存在的顺式作用元件,我们将水稻ｗａｘｙ基因翻译起始声、（ＡＴＧ）５＇上游３．４ｋｂ（－２１１８～＋１２９１ｂＰ）片段经外切核酸酶ＥｘｏⅢ部分酶解,得到一系列５＇端缺失的片段。将这些缺失片段分别与ｇｕｓ基因编码区连接,构建成融合质粒,经ＰＥＧ介导引入水稻原生质体,２６℃培养４８ｈ后,定量测定ＧＵＳ酶活力,并以同时导入的由３５Ｓ启动子指导的荧光素酶（ＬＵＣ）基因表达的酶活力作为内对照。结果表明,ＧＵＳ酶活性随５’上游调控区长度的减少而逐渐减弱。由─８６１ｂｐ缺失至─６４０ｂＰ时,ｇｕｓ基因表达水平有较明显的降低,推测在该区域中可能存在一个顺式作用元件区。     

Structure and expression of a rice hsp70 gene

A genomic hsp70 gene was isolated from a rice IR36 genomic library and 4 794 bp of the gene have been sequenoed. The 5' flanking region of the gene contained a putative TATA box and a typical heat shock element sequence 5'-CTcgGAAccTTCgAG-3'. The amino acid sequence of the rice HSP70 deduced from the coding region shared 84%-92% homologies with those of HSP70s from other plant species. An intron 1939bp long was identified in the coding region at the codon specifying amino acid 72 (Asp), the similar position introns occurring in other intron-containing hsp70 genes. In addition, another intron of 57 bp was found in the 3'-untranslated region in the rice hsp70 gene. Southern blot hybridization showed that rice hsp70 gene family contained at least three members. Analysis of the RNA leveis with the gene-specific and non-specific probes revealed that the rice hsp70 gene expressed at normal temperature and the expression was enhanced by heat shock treatment.     

红壤旱坡地桔园覆盖的生态效应及经济效益评价

柑桔是南方红壤地区栽培的主要果树种类,栽培面积达1126×106ｈｍ2。柑桔是一种常绿果树,生长量大,挂果期长,周年需要消耗大量的水分。我国南方红壤地区虽然雨水充沛,但降水季节分布不均,柑桔果实迅速生长的7～10月正是该地区雨水少、蒸发量大的伏秋干旱季节。经常性的伏秋干旱是制约我国柑桔产量和质量进一步提高的主要障碍因素之一。桔园夏秋进行秸秆覆盖可以降温[1]、保水[2]、防止杂草生长[3]等,但桔园应用地膜覆盖及常年连续覆盖对桔园的生态效应方面的研究较少,为此我们开展了这方面的工作,并通过连续3ａ的产量及产值分析覆盖桔园的经…     

北方稻田生态系统水量平衡及水分效率研究

１９９３～１９９５年研究了５种不同模式水稻田生态系统水量平衡及水分效率结果表明,不同水稻田模式其总耗水量之间有明显差异,其中节水模式和节水节肥模式较常规模式节省灌溉水达１５～２３％,水分生产效率增加３０％以上．各模式蒸发蒸腾耗水量在同一生长季内基本相同．田间结构及调控管理对其无明显影响实测水稻生育期田间蒸发蒸腾量与计算的可能蒸发蒸腾量相差不过５％。     

北方稻田生态系统研究Ⅱ．稻萍结合系统细绿萍共生固N量研究

对稻萍结合系统细绿萍共生固Ｎ量研究表明,萍的固Ｎ力在整个生长季不同时期有所变化．最高固Ｎ率出现在６月初,萍固Ｎ量随其接种量和水稻行距增加而增加．５０～１０ｃｍ宽窄行交替的水稻行距和１５００ｋｇ·ｈｍ－２的萍接种量的稻萍结合系统的总固Ｎ量为１０７．１ｋｇ·ｈｍ－２,而３０ｃｍ等行距的３２５ｋｇ·ｈｍ－２的萍接种量的稻－萍结合系统的总固Ｎ量仅为３６．０ｋｇ·ｈｍ－２     

不同育秧方式和插植密度下晚籼稻群体动态结构的研究

不同育秧方式和插植密度下晚籼稻群体动态结构存在差异。旱育秧群体分蘖速度快,分蘖能力强。稀植可促进个体分蘖多发、有效穗数增多,但旱育稀植并无分蘖早发的优势。旱育稀植使主茎基部叶片变短而上部叶片变长,生育后期叶面积消长平稳,地上部干物质积累较多。旱育秧、稀植都使主茎叶总数增多,全生育期延长。     

水稻叶片对模拟酸雨伤害的生理反应

水稻暴露于ｐＨ２．５～４．２的模拟酸雨中２个月后测定表明：叶片叶绿素含量下降,细胞液离子外渗率增加,气孔阻抗增高,蒸腾速率降低。不同叶位的水稻叶片对模拟酸雨的敏感性不同,杂交稻（汕优６３）对模拟酸雨的敏感性较粳稻（中粳８６４）高     

Disruption of microfilaments alters laminin synthesis but not laminin trafficking in NHEKin vitro

Summary Laminin synthesis and deposition are concomitant with the development of a basal lamina between the human epidermis and the underlying dermis. One of the challenges in tissue engineering of human epidermal models is to develop substrates and conditions that encourage the development of a basement membrane. The purpose of this study was to determine if actin filaments and/or microtubules are involved in the synthesis/secretion of laminin by normal human epidermal keratinocytes (NHEK)in vitro. NHEK synthesize and secrete laminin subunits B1, B2, and M but little, if any, of laminin subunit A. Data indicate that disruption of microfilaments by the destabilizing agent, cytochalasin D, had no apparent effect on the relative synthesis rates of most cytosolic proteins as, revealed by one-dimensional sodium dodecyl sulfate (SDS) gel electrophoresis. This drug, however, increased laminin B2 synthesis several fold over untreated controls. This enhanced synthetic rate was independent of the type of collagen, matrix on which the NHEK were grown. Similar increases in synthesis of the M and B1 laminin chains were not observed. To determine if this increase in synthesis lead to increases in laminin B2 secretion, laminin B2 was immunoprecipitated from both the apical and basal domains of NHEK cells grown on microporous membranes. While more laminin B1, B2, and M were secreted basally than apically, an observation consistent with laminin’s role in basal lamina formation, cytochalasin D had no apparent effect on either basal or apical laminin B2 secretion. Experiments with the microtubule destabilizer, nocodazole, showed no similar effects on laminin synthesis and/or secretion. We conclude that (a) disruption of the actin network in NHEK selectively increases the synthesis of laminin B2, (b) the secretion of laminin B2 from NHEK cells is not governed by either the microfilamentous cytoskeleton or the amount of laminin synthesized by NHEK, and (c) disruption of the microtubular network does not alter laminin synthesis or secretion.     

Intraspecific Variation in Chemical Attraction of Rice to Insect Predators

The olfactory response of predators of the brown planthopper,Nilaparvata lugensStål, to different genotypes of rice (14 cultivars and breeding lines ofOryza sativaL. and 1 wild species,Oryza nivaraSharma et Shastry) was measured in an airflow olfactometer. Odor from rice plants attracted more females of the mirid predatorCyrtorhinus lividipennisReuter than plain air (control) on only 6 of the 15 rice genotypes. Orientation ofC. lividipennistoward volatiles of certain rice genotypes was apparent even when the plants were free of the brown planthopper. However, the predator distinguished between prey-infested and uninfested plants and preferred plants with eggs over plants with nymphs. The predator did not distinguish different stages of plant growth (vegetative, booting, or flowering). Plants artificially injured to simulate brown planthopper oviposition wounds were not as attractive to the predator as plants on which the planthopper had oviposited. The preassay preconditioning on the cultivar TN1 did not produce a predator bias for this genotype. This suggests that rearing effects or chemically mediated associative learning reported for some natural enemies did not influenceC. lividipennis'host response. Results with another predator, the coccinellidMicraspis hirashimaiSasaji, produced less consistent behavior. Planthopper-infested plants attracted more females ofM. hirashimaithan unifested plants in only 1 of the 12 rice genotypes evaluated. Implications for augmenting predators by rice cultivar selection and modification are discussed.