Acclimation abilities of three tropical rainforest seedlings to an increase in light intensity

Current practices in many nurseries involve the germination of tropical rainforest seedlings in shaded conditions and transferral, at a later date, to environments with greater light intensities. Determination of the ability of these seedlings to acclimate to increased light intensities will allow seedling stock to be processed with maximum efficiency within the nursery. The acclimation abilities of three species, Agyrodendron actinophyllum, Cardwellia sublimis, and Flindersia brayleyana, commonly found in north Queensland's rainforests were investigated in this study. These particular species are highly valued for their cabinet timber qualities and are being reared in nurseries for use in reforestation trials and programs in north Queensland. Seedlings were initially raised in greenhouse conditions under two layers of shade cloth (16% of full sunlight) and then transferred into full sunlight at three different ages (3 weeks, 10 weeks, 14 weeks). Upon transfer, organ ratios and the direction of dry matter distribution was determined for each species and age group. Approximately 3 months after the seedlings were transferred, the acclimation ability of each species and age group was then determined. Dry matter distribution was found to change with age, irrespective of light environment. Individuals within a species with larger root systems and thicker or more dense leaves had a greater acclimation ability than those with smaller root systems and thinner or less dense leaves. Furthermore, individuals within a species whose dry matter distribution upon transfer was directed towards developing a large root system, and a small photosynthetic area and mass, had a greater acclimation ability than those whose dry matter distribution was directed away from such morphologies. Awareness of these relationships allows a better understanding of seedling response to gap formation in natural forests, and also allows plant nursery operators to make a more informed decision about when to move seedlings to environments with a higher light intensity.     

植物在水分胁迫下脯氨酸积累的研究─—Ⅳ关于植物体内脯氨酸积累的直接触发因子

依据干旱胁迫下数种植物幼苗体内游离脯氨酸、叶气孔、叶水量的变化，剖析了植物与环境因子、气孔因子、氧气因子、酶因子及能量因子之间的相互依存关系，提出了ＰＲＯ积累系统（ＰＡＳ）。认为水分胁迫下植物体内ＰＲＯ的大量积累是氧化受抑和合成受激共同调控的结果。氧气最有可能为直接触发因子。     

胞质雄性不育性在叶用芥菜上的利用

以从美国威斯康星大学引进的叶用芥菜胞质雄性不育系叶用4-4为母本,以泰国清迈大学选育出的8个优良叶用芥菜品种为转育父本,杂交后连续回交4代(BC4),再将BC4与优良叶用芥菜品种40R2-3-4配制8个杂交组合,其中2个组合(4-4 × 19-H-12)×40R2-3-4和(4-4 × 2R2)×40R2-3-4结球率为100％,产量比商用品种分别高34％和13％,比其亲本分别高25％和5％。     

31个杂交杨无性系对青杨叶锈病的抗性评价

在大田条件下对从北美新引种的31个杂交杨无性系对青杨叶锈病的抗性进行调查和评价的结果表明:所引进无性系对杨树叶锈病的抗性表现出很大的差异,从高度抗病到高度感病均有,但没有免疫的无性系。HE-2,XMH-10,XMH-9,HE-1,XMH-1,XMH-11,XMH-12,XMH-2,MH-8,XMH-7这10个无性系表现出高度抗病性,MH-9,DMH-3,MH-10,MH-4,MH-1,MH-6,MH-7,MH-2这8个无性系表现为高度感病。DN、NE杂交的大多数无性系有较高的抗病性,而TD、TN杂交的绝大多数无性系为感病或高度感病。同一杂交组合的不同无性系间,其抗性存在很大差异,有高抗,也有高感。     

基于神经网络的树叶识别系统研究

在林业系统注册树木种类时,通常采用大量树叶上的可见外形特点来辨别数目繁多的树木种类。针对此问题,本文提出了基于神经网络的树叶识别方法,该方法建立并管理一个分等级的树叶图像体系,通过对不同种类树叶的边缘提取来识别每种树叶的特征点,从而得到树叶的外部轮廓来区分树木种类:给出了相应的改进型神经网络算法,并给出详细的论述过程:最后,通过Java语言给出了系统实现并做了大量的数值仿真。结果证明本文方法是可行有效的。图4表1参8。     

152个黄淮地区小麦主要品种(系)的多抗性鉴定

为给小麦抗病抗虫育种提供依据,于2004～2006年在山东济南对152份来自黄淮地区的小麦主栽品种(系)进行了抗小麦条锈病、叶锈病、白粉病及蚜虫鉴定.结果表明,在供试品种(系)中表现高抗条锈病的品种(系)占46.71%,中抗品种占25.66%;高抗叶锈病的品种占23.68%,中抗品种占24.34%;高抗白粉病的品种占28.29%,中抗品种占55.92%;高抗蚜虫的品种(系)占5.26%,中抗品种占13.16%.综合来看,对小麦条锈病、叶锈病和白粉病表现中抗以上的品种(系)47个,占30.92%;兼抗(中抗以上)小麦条锈病、叶锈病、白粉病和麦蚜的有5个品种(系),占3.29%.     

高光谱遥感森林叶面积指数估测研究现状

文中简要概述了叶面积指数和高光谱遥感的概念, 分析比较了高光谱遥感与传统的宽波段遥感估测森林叶面积指数的优势, 以及利用高光谱遥感数据估测森林叶面积指数的常用方法, 并对目前高光谱遥感估测森林叶面积指数存在的问题行了讨论。     

基于GF-6/WFV卫星遥感的大田冬小麦叶片氮素含量估测

为对大田冬小麦叶片氮素含量（LNC）进行快速、准确及无损监测,通过在江苏省泰州泰兴市、盐城大丰区和南通如皋市布设冬小麦遥感监测大田试验,在获取试验样点冬小麦冠层红光波段反射率（RED_ref）、近红外波段反射率（NIR_ref）和计算的十个光谱指数（RVI、NDVI、DVI、SAVI、OSAVI、MSR、RDVI、EVI2、NLI和SVI）基础上,将12个遥感光谱指标与冬小麦LNC进行相关分析,选出与LNC相关性较好的作为模型输入变量,构建基于BP神经网络的冬小麦LNC估测模型, 并利用GF-6/WFV卫星遥感影像对县域冬小麦LNC的空间分布开展监测。结果表明,12个遥感光谱指标与冬小麦LNC之间存在不同程度的相关性,其中NDVI、RVI、MSR、OSAVI和NLI与冬小麦LNC的相关性较好（相关系数不低于0.65）。将优选的5个遥感光谱指标作为模型输入变量,构建基于BP神经网络的冬小麦LNC估测模型（LNC-BPEM）,模型的估测精度r²=0.866,RMSE=0.246%,ARE=12.9%。将冬小麦LNC-BPEM估测模型和GF-6/WFV影像结合对县域冬小麦LNC的空间信息监测,获得了如皋县域冬小麦LNC的空间分布特征,该区域冬小麦LNC范围在0.9%~2.0%（长势正常）的种植面积为29 693.3 hm²,占冬小麦总种植面积的74%。这说明利用GF-6/WFV卫星的多个遥感光谱指标与神经网络结合建模可有效估测县域大田冬小麦叶片氮素含量。     

不同光照处理下外施营养液和激素对万圣节法师叶色变化的影响[1]

To study the effects of light, external nutrition, and hormones on the color changes of Aeonium aeonium "Halloween" leaves. In this study, the 1-year-old stem cuttings of the Aeonium aeonium "Halloween" were used as materials. The leaves were sprayed with 25mg/L methyl jasmonic acid, 3‰ potassium dihydrogen phosphate, and 1‰ calcium magnesium boron mixture for two consecutive times, with an interval of 3 days. The experiment consisted of CK (water control), LS, DS (dark culture for 1 week). After 1 week of treatment, the leaf color parameters and anthocyanin pigment content were measured every 7 days for 6 consecutive weeks. The results showed that the treatment time and method had a significant impact on the leaf color parameters. In terms of brightness value L, as the treatment time extended, all three treatments showed an upward downward upward trend. Among them, the highest value was reached after 2 weeks of treatment, gradually decreased after 3 weeks, and sharply increased again after 6 weeks; In terms of red green saturation a value, after 2-4 weeks of treatment, both LS and DS treatments were significantly higher than CK, and the effect significantly decreased after 5 weeks; Light has a significant impact on a value, with DS treatment showing a significant decrease in a value after one week of shading, and a sharp increase after re lighting; In terms of the b value of yellow and blue saturation, the change in CK value is relatively small with the extension of treatment time, while the fluctuation in LS and DS treatment is significant; In terms of color saturation c value, DS treatment significantly increased with the prolongation of treatment time, and there was no significant change in LS and CK treatment within 1-3 weeks. After 3 weeks of treatment, there was no significant difference between the three treatments; With the extension of treatment time, the anthocyanin content of each treatment showed a trend of first increasing and then decreasing. After 2-3 weeks of treatment, the anthocyanin content was higher, and gradually decreased after 4 weeks of treatment; Correlation analysis shows that anthocyanin content is highly significantly positively correlated with a and c values, and anthocyanin content is a key factor in the red color of Aeonium aeonium "Halloween".     

黄瓜叶面积测量方法的评价

采用方格纸法、等腰三角形法及数码相机拍照法测定黄瓜叶面积。结果表明,采用这3种方法测定的结果差异不显著。综合考虑耗时、信息量、先进性等因素,数码相机拍照法为最优测定方法。