土壤盐胁迫下杨树次生木质部的解剖特征

对生长在苏北沿海防护林不同土壤盐度下的主栽树种杨树(欧美杨无性系69杨)进行了解剖,描述了杨树次生木质部结构的特征,测量了次生木质部的16个数量特征：年轮宽度(ARW)、导管长度(VL)、早材和晚材的导管分子面积(VA)、导管周长(VP)、导管直径(VD)、导管单孔率(PSV)、导管频率(VF)、纤维长度(FL)、纤维宽度(FW)、射线高度(RH)和射线频率(RF)。实验结果表明,在不同的土壤盐度胁迫下：(1)杨树次生木质部形态特征的差别不明显,但是组成分子趋向于小型化。(2)次生木质部数量特征的变化比较明显,即当土壤含盐量从0．036％逐渐升高到0．289％,杨树的年轮宽度变小,0．91→0．77mm;纤维长度和宽度的变化分别为693．8→570μm和14．9→13．5μm,射线高度和频率的变化分别为284．3→249．2μm和58．9→75．5mm^-2,表明在盐胁迫下杨树的生长受到抑制。随着盐度的增加0．036％→0．289％,杨树导管长度减小,367．6→341．5μm;在早材和晚材中,导管面积变化分别为1575．6→1703．6μm^2和760．1→947．7μm^2,导管周长变化分别为167．7→195．1μm和120．8→143．7μm,导管直径的变化分别为41．8→43．4μm和29．1→33．1μm,导管频率的变化分别为141．8→144．2mm^-2和160→206．7mm^-2;导管单孔率的变化分别为65．9％→30．5％和59．4％→40．8％。这些都表明在盐胁迫下杨树的导管缩短变粗,呈聚集分布,输水效率和输水安全性都有所提高。     

从天葵药材的解剖结构探讨其形态本质

天葵"块根"是由主根及下胚轴共同膨大形成,天葵药材的形态本质应为肉质直根。天葵肉质直根的增粗主要原因是由于木薄壁细胞产生三生形成层,形成大量三生维管束;以及次生韧皮部和次生木质部中薄壁细胞的不断增加。     

Deficit irrigation based on drought tolerance and root signalling in potatoes and tomatoes

Agriculture is a big consumer of fresh water in competition with other sectors of the society. Within the EU-project SAFIR new water-saving irrigation strategies were developed based on pot, semi-field and field experiments with potatoes (Solanum tuberosum L.), fresh tomatoes (Lycopersicon esculentum Mill.) and processing tomatoes as model plants. From the pot and semi-field experiments an ABA production model was developed for potatoes to optimize the ABA signalling; this was obtained by modelling the optimal level of soil drying for ABA production before re-irrigation in a crop growth model. The field irrigation guidelines were developed under temperate (Denmark), Mediterranean (Greece, Italy) and continental (Serbia, China) climatic conditions during summer. The field investigations on processing tomatoes were undertaken only in the Po valley (North Italy) on fine, textured soil. The investigations from several studies showed that gradual soil drying imposed by deficit irrigation (DI) or partial root zone drying irrigation (PRD) induced hydraulic and chemical signals from the root system resulting in partial stomatal closure, an increase in photosynthetic water use efficiency, and a slight reduction in top vegetative growth. Further PRD increased N-mineralization significantly beyond that from DI, causing a stay-green effect late in the growing season. In field potato and tomato experiments the water-saving irrigation strategies DI and PRD were able to save about 20-30% of the water used in fully irrigated plants. PRD increased marketable yield in potatoes significantly by 15% due to improved tuber size distribution. PRD increased antioxidant content significantly by approximately 10% in both potatoes and fresh tomatoes. Under a high temperature regime, full irrigation (FI) should be undertaken, as was clear from field observations in tomatoes. For tomatoes full irrigation should be undertaken for cooling effects when the night/day average temperature >26.5 °C or when air temperature >40 °C to avoid flower-dropping. The temperature threshold for potatoes is not clear. From three-year field drip irrigation experiments we found that under the establishment phase, both potatoes and tomatoes should be fully irrigated; however, during the later phases deficit irrigation might be applied as outlined below without causing significant yield reduction:

•

Potatoes

°

After the end of tuber initiation, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

•

Fresh tomatoes

°

From the moment the 1st truce is developed, DI is applied at 85-80% of FI for two weeks. In the middle period, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

•

Processing tomatoes

°

From transplanting to fruit setting at 4th-5th cluster, the PRD and DI threshold for re-irrigation is when the plant-available soil water content (ASWC) equals 0.7 (soil water potential, Ψ_soil = −90 kPa). During the late fruit development/ripening stage, 10% of red fruits, the threshold for re-irrigation for DI is when ASWC = 0.5 (Ψ_soil = −185 kPa) and for PRD when ASWC (dry side) = 0.4 (Ψ_{soil, dry side} = −270 kPa).

The findings during the SAFIR project might be used as a framework for implementing water-saving deficit irrigation under different local soil and climatic conditions.     

Investigations on the inheritance of color and carotenoid content in phloem and xylem of carrot roots (Daucus carota L.)

Summary Investigations on the inheritance of root color in carrot (Daucus carota L.) were carried out by crossing uniformly colored roots to various tinge type roots, i.e. roots of which the xylem differs in color from the phloem.A single major gene (Y) was found to be responsible for the observed differences in progenies of orange x tinge orange-white (orange referring to phloem color, white to xylem color) crosses. Plants carrying the dominant Y-allele had either white or tinge orange-white roots, whereas plants with orange roots were of the genotype yy. Similarly one major gene (Y ₂) determined the segregation found in progenies of orange x yellow crosses. In the latter crosses, plants having the dominant Y ₂-allele had either yellow or tinge orange-yellow roots while the recessive would be orange. Variation in phloem color, i.e. differences between white and tinge orange-white or between yellow and tinge orange-yellow, was apparently caused by minor genes, modifiers, gene interactions, or by genes that are not involved in carotenogenesis in a direct way.When both the Y- and Y ₂-genes were present, the roots were always white. Usually white roots gave a digenic segregation pattern in the F₂ when crossed to orange, but there was some evidence that a third gene (Y ₁) was segregating in some crosses. Tinge orange-white x yellow crosses gave approximately the same results as orange x white crosses, confirming that the same Y- and Y ₂-genes were segregating.In crosses between orange lines and a light yellow line (RY) certain F₁ 's appeared to have a light orange xylem and a fairly dark orange phloem, which seems to be some evidence for the existence of recessive yellow. Although almost nothing is known yet about the genetics of RY it is assumed that it still carries a dominant inhibitor gene which may be leaky in heterozygous condition. The value of such a line as an aid in the selection of superior orange lines is discussed.Alpha- and beta-carotene were found to be the major pigments in orange carrot tissue; phytofluene, zetacarotene, gamma-carotene and xanthophylls were shown to be present in smaller amounts. Besides xanthophylls and a small amount of beta-carotene dark yellow carrot tissue appeared to contain an appreciable amount of an unidentified pigment (pigment I). Light yellow and white phloem or xylem tissue were low in total carotenoids.Research supported by the College of Agricultural and Life Sciences and by a grant from the Campbell Soup Company, Camden, New Jersey, USA. The investigation is a portion of a thesis submitted in 1978 as partial fulfillment of the requirements of the PhD degree.     

采用K均值聚类和环形结构的狭叶锦鸡儿木质部提取算法

针对木质部交互统计误差大、效率低、重现性差、劳动强度高和传统图像处理算法精度不理想等问题,该文以狭叶锦鸡儿木质部切片图像为研究对象,根据木质部特点提出基于K均值聚类算法和环形结构提取算法相结合,实现木质部准确提取的方法。首先通过动态巴特沃斯同态滤波法对30幅供试图像进行光照不均校正,然后采用K均值聚类法对光照补偿后图像初分割,最后采用环形结构提取算法实现木质部提取计数。试验结果表明:采用K均值聚类算法对光照补偿后的木质部图像初分割分割误差R(section error, R)、过分割误差OR(over-segmentation error, OR)和欠分割误差UR(under-segmentation error, UR)均值分别为5.15%、1.48%和6.46%,优于未光照补偿和3R-G-B算法;该文提出的环形结构提取算法对初分割后木质部图像检测的平均相对误差为2.26%,比分水岭法低11.69个百分点,比凹点匹配法低4.93个百分点。从速度上看,该算法平均耗时3.17 s,比分水岭法快1.40 s,比凹点匹配法快4.88 s。该算法检测的均方根误差RMSE(root mean squared error, RMSE)为0.52%,约相当于分水岭法的1/3,约相当于凹点匹配法的1/2,该算法优于其他2种分割算法;在图像结构复杂、光照不均匀、内部分布不均等缺陷条件下,该文算法也能很好地实现木质部的分割和提取。该方法不仅能对狭叶锦鸡儿木质部自动分割和提取,也可为其他植物木质部分割提取提供参考。     

转基因（反义ACS和反义Nr）番茄伤流中植物激素的运输＊

以转反义ACS（ACC合成酶）和反义NR（乙烯受体蛋白）基因番茄和普通番茄（Lycopersicon escclentum Mill．）作为试材，通过ELISA（enzyme-linked immunosorbent assay）方法研究了抑制乙烯合成的外源基因转入番茄后，伤流中植物激素的变化。发现转基因番茄和普通番茄在盛花期和盛果期伤流中各种植物激素的含量变化不显著；而到了成熟期伤流中IAA、GA，和CTKs（细胞分裂素）仍然没有显著变化，但转基因番茄伤流中ABA含量与普通番茄相比却显著减少，说明ABA和乙烯对番茄成熟衰老的控制是共同起作用的，乙烯释放量的改变和信号转导途径的抑制都会影响ABA的伤流运输。     

邻苯二酚对切花保鲜效果的影响

采用不同浓度的邻苯二酚及8-HQC和蔗糖组成的保鲜剂对香石竹、月季、换锦花、非洲菊进行保鲜处理,研究其对切花寿命的影响。结果表明:1m M邻苯二酚组成的保鲜剂可以显著延长香石竹、换锦花、非洲菊和月季切花的寿命。     

PP_(333)对温室葡萄枝条次生木质部细胞解剖结构的影响

为了研究设施栽培条件下葡萄木质部细胞的特征性结构及其受PP_(333)的影响,试验通过对温室葡萄喷施PP_(333)后的枝条次生木质部细胞的解离、观察,经统计分析,结果表明:(1)不同浓度PP333处理对各类型细胞的X形态结构没有明显影响;(2)浓度不同对各类细胞的长度和直径抑制作用不同,喷施1500mg/L浓度的PP_(333)对其营养生长的抑制效果最好。通过该试验的研究,为更好地探索设施栽培条件下果树的生理生态特征和化学调控技术提供了依据。     

Direct infection of potato tubers by the root parasite Orobanche aegyptiaca

Parasitic plants of the Orobanchaceae are known as obligate root parasites that develop haustoria that connect to roots of various host plants. This article describes, for the first time, a case where the root parasite successfully connected to potato tubers, i.e. to the swollen portion of an underground stem rather than to a root. The rhizosphere of Orobanche aegyptiaca and of its host Solanum tuberosum (potato) was carefully examined. In anatomical studies, the adventitious roots were directly connected to potato tubers. Numerous secondary haustoria, which developed along the adventitious roots in close vicinity to the potato tuber, penetrated the tuber epidermis and the perimedullary tuber parenchyma and developed xylem strands that are presumably connected to the minor xylem strands within the tuber cortex. These findings indicate that parasites of the Orobanchaceae that normally attack host roots may also parasitise underground stem tubers.     

马尾松茎木质部产生与水热关系的初报

在马尾松年生长周期中，定位逐月采样，比较解剖形成层活动的数量和产生木质部的结构与旬均温和旬雨量的关系．纺锤状原始细胞的分裂次数明显受温度控制，在月均温１３．５～２９．３℃的活动期中，以１７．１～２７．８℃分裂较快，并有一定抗旱性；在连续旬雨量１０ｍｍ以下，仍能形成纺锤状细胞．管胞分化的下限温度约１１℃，雨量是调节管胞腔径及壁、腔比值变化的主要因素．木射线细胞的生长受管胞结构的影响，其长和宽的扩大分别随管胞腔径和壁、腔比值提高而增加，在正常温度范围内，间隔性干旱有促进树脂道的形成．