Predicting walnut (Juglans spp.) crop yield using meteorological and airborne pollen data

Crop yield determines economy by influencing prices on the trade market, and so accurate forecasts of the yield are important for planning various aspects of agricultural production. The main aim of this study is to construct a model for predicting walnut yield in an important walnut production area (the region of Novi Sad in Northern Serbia). Relationships between the amount of walnuts produced annually (2000–2011) and abiotic (e.g. meteorological) and biotic (e.g. airborne pollen data) factors were examined using Pearson correlation analysis. Walnut yield data were then entered into linear regression models with variables that had the highest correlations. The models were constructed using 10 years of data, and tested using 2 years of data not included in constructing the model. This paper has shown that walnut yield is greatly dependent on weather conditions, particularly during fertilisation and seed growth, but the amount of available airborne pollen also plays an important role. The introduction of the seasonal pollen index, as a proxy for the amount of pollen available for fertilisation, improved the performance of models predicting walnut yield.     

Morphogenesis of Pistillate Flowers of Cercidiphyllum japonicum(Cercidiphyllaceae)

Floral morphogenesis and the development of Cercidiphyllum japonicum Sieb.et Zucc.were observed by scanning electronmicroscopy(SEM).The results showed that the pistillate inflorescences were congested spikes with the flowers arrangedopposite.Great differences between the so-called"bract"and the vegetative leaf were observed both in morphogenesis andmorphology.In morphogenesis,the"bract"primordium is crescent-shaped,truncated at the apex and not conduplicate,has no stipule primordium at the base but does have some inconspicuous teeth in the margin that are not glandular.Theleaf primordium is triangular,cycloidal at the apex,conduplicate,has two stipule primordia at the base,has one gland-toothat the apex occurring at first and some gland-teeth in the margin that occur later.In morphology,the"bract"is also differentto the vegetative leaf in some characteristics that were also illustrated in the present paper.Based on the hypothesis thatthe bract is more similar to the vegetative leaf than the tepal,we considered that the so-called"bract"of C.japonicum mightbe the tepal of the pistillate flower in morphological nature.Therefore,each pistillate flower contains a tepal and a carpel.We did not find any trace of other floral organs in the morphogenesis of the pistillate flower.Therefore we consideredthat the unicarpellate status of extant Cercidiphyllum might be to highly reduce and advance characteristics that make theextant Cercidiphyllum isolated from both fossil Cercidiphyllum-like plants and its extant affinities.     

小叶桦花序生长物候及其生态适应意义

小叶桦(Betula microphylla)是一种典型的荒漠和山地乔木植物,在中国仅分布于新疆。为了明确小叶桦花序生长物候规律及发育特征,该研究对小叶桦进行了花序物候观测,分析其生长规律及果实结籽情况。结果显示:小叶桦雄花序为越年生殖器官,物候周期为345d,其中营养生长期154d、休眠期158d、开花生长期33d;雌花序与果序为当年生殖器官,物候期为105d,其中雌花序生长期24d、果序生长期90d。虽然雄花序比雌花序的生长周期明显较长,但开花授粉均在4月中下旬,雄花序散粉期和雌花序可授粉期之间具有较高的同步性和协调性,表现出集中开花授粉模式,同时这种开花模式在自然条件下,果序的结籽数和结籽率分别为220和76.7%,种子库中具有活力的种子约每平米4万粒,表明小叶桦在荒漠极端环境中能顺利完成有性生殖过程。     

Comparative floral development in male and female plants of Palmer amaranth (Amaranthus palmeri)

Premise

Characterizing the developmental processes in the transition from hermaphroditism to unisexuality is crucial for understanding floral evolution. Amaranthus palmeri, one of the most devastating weeds in the United States, is an emerging model system for studying a dioecious breeding system and understanding the biological traits of this invasive weed. The objectives of this study were to characterize phases of flower development in A. palmeri and compare organogenesis of flower development in female and male plants.

Methods

Flower buds from male and female plants were dissected for light microscopy. Segments of male and female inflorescences at different stages of development were cut longitudinally and visualized using scanning electron microscopy.

Results

Pistillate flowers have two to three styles, one ovary with one ovule, and five obtuse tepals. Staminate flowers have five stamens with five acute tepals. Floral development was classified into 10 stages. The distinction between the two flower types became apparent at stage four by the formation of stamen primordia in staminate flowers, which developed female and male reproductive organs initially, as contrasted to pistillate flowers, which produced carpel primordia only. In staminate flowers, the putative carpel primordia changed little in size and remained undeveloped.

Conclusions

Timing of inappropriate organ termination varies across the two sexes in A. palmeri. Our study suggests that the evolution of A. palmeri from a cosexual ancestral state to complete dioecy is still in progress since males exhibited transient hermaphroditism and females produced strictly pistillate flowers.     

Floral anatomy of Paepalanthoideae (Eriocaulaceae, Poales) and their Nectariferous structures

BACKGROUND AND AIMS: Eriocaulaceae (Poales) is currently divided in two subfamilies: Eriocauloideae, which comprises two genera and Paepalanthoideae, with nine genera. The floral anatomy of Actinocephalus polyanthus, Leiothrix fluitans, Paepalanthus chlorocephalus, P. flaccidus and Rondonanthus roraimae was studied here. The flowers of these species of Paepalanthoideae are unisexual, and form capitulum-type inflorescences. Staminate and pistillate flowers are randomly distributed in the capitulum and develop centripetally. This work aims to establish a floral nomenclature for the Eriocaulaceae to provide more information about the taxonomy and phylogeny of the family. METHODS: Light microscopy, scanning electron microscopy and chemical tests were used to investigate the floral structures. KEY RESULTS: Staminate and pistillate flowers are trimerous (except in P. flaccidus, which presents dimerous flowers), and the perianth of all species is differentiated into sepals and petals. Staminate flowers present an androecium with scale-like staminodes (not in R. roraimae) and fertile stamens, and nectariferous pistillodes. Pistillate flowers present scale-like staminodes (except for R. roraimae, which presents elongated and vascularized staminodes), and a gynoecium with a hollow style, ramified in stigmatic and nectariferous portions. CONCLUSIONS: The scale-like staminodes present in the species of Paepalanthoideae indicate a probable reduction of the outer whorl of stamens present in species of Eriocauloideae. Among the Paepalanthoideae genera, Rondonanthus, which is probably basal, shows vascularized staminodes in their pistillate flowers. The occurrence of nectariferous pistillodes in staminate flowers and that of nectariferous portions of the style in pistillate flowers of Paepalanthoideae are emphasized as nectariferous structures in Eriocaulaceae.     

Morphogenesis of Pistillate Flowers of Cercidiphyllum japonicum （Cercidiphyllaceae）

Floral morphogenesis and the development of Cercidiphyllumjaponicum Sieb. et Zucc. were observed by scanning electron microscopy （SEM）. The results showed that the pistillate inflorescences were congested spikes with the flowers arranged opposite. Great differences between the so-called ＂bract＂ and the vegetative leaf were observed both in morphogenesis and morphology. In morphogenesis, the ＂bract＂ primordium is crescent-shaped, truncated at the apex and not conduplicate, has no stipule primordium at the base but does have some inconspicuous teeth in the margin that are not glandular. The leaf primordium is triangular, cycloidal at the apex, conduplicate, has two stipule primordia at the base, has one gland-tooth at the apex occurring at first and some gland-teeth in the margin that occur later. In morphology, the ＂bract＂ is also different to the vegetative leaf in some characteristics that were also illustrated in the present paper. Based on the hypothesis that the bract is more similar to the vegetative leaf than the tepal, we considered that the so-called ＂bract＂ of C.japonicum might be the tepal of the pistillate flower in morphological nature. Therefore, each pistillate flower contains a tepal and a carpel. We did not find any trace of other floral organs in the morphogenesis of the pistillate flower. Therefore we considered that the unicarpellate status of extant Cercidiphyllum might be to highly reduce and advance characteristics that make the extant Cercidiphyllum isolated from both fossil Cercidiphyllum-like plants and its extant affinities.     

Flower structure and potential bisexuality in Freycinetia reineckei (Pandanaceae), a species of the Samoa Islands

In Freycinetia reineckei the staminate flower (on the staminate spikes) comprises 3 or 4 (sometimes 2) stamens and a pistillode with 2 (sometimes 4) carpellodes, and the pistillate flower (on the pistillate spikes) is formed of a pistil with 2 (sometimes 4) carpels and of 3 or 4 (sometimes 2) staminodes. This perfect floral homology, also observed in all the other species that were studied with both pistillate and staminate material, strongly suggests that the flower of Freycinetia is basically and potentially bisexual, and may explain the occasional sexual lability and bisexuality of that flower (occurrence of both pistillate and staminate inflorescences, and/or of bisexual inflorescences with bisexual flowers and/or unisexual flowers, on the same individuals) in some species, and also the frequent occurrence of bisexual spikes in this species. These may be partitioned into pistillate, staminate, mixed and sterile zones. In the pistillate zones the flowers have the same aspect and structure as the pistillate flowers. In the staminate zones the flowers generally comprise 3 or 4 (sometimes 2) stamens and a ‘semi-pistil’ some have both stamens and staminodes. The semi-pistils are intermediate between pistils and pistillodes in length, aspect and structure, but always have placentas and ovules. In the mixed zones the flowers are generally formed of a pistil and 3 or 4 (sometimes 2) stamens, and are therefore true hermaphrodite flowers; some have both stamens and staminodes. In the sterile zones the flowers comprise a semi-pistil and 3 or 4 (sometimes 2) staminodes. The staminodes are anatomically very similar to the stamens, especially in the staminate, mixed, and sterile zones, in which they exhibit a wide range of variation in length, aspect and structure. The perfect floral homology as generic character on one hand, and the occasional bisexuality both with and without bisexual flowers and other aspects of sex expression (e.g. occurrence of both pistillate and staminate shoots on the same individuals) in some species on the other hand, seem to indicate that Freycinetia is a basically monoecious, sex changing genus.     

黄瓜复雌花等6对基因间连锁遗传关系的研究

为探索黄瓜复雌花基因mp、有限生长基因de、叶片皱缩基因cr、叶片无毛基 因gl-2、果皮多刺基因ns和果实有棱基因Tu间的独立或连锁遗传关系,试验选用了带上述6对基因的黄瓜纯合亲本NCG128、NCG 157、WI 275 7和NCG 042,以这些亲本配制4个杂交组合,获得F1,F2,BC1a和BC1b代群体,采用孟得尔遗传公式和计算机程序分析参试性状在各杂交后代中的基因型分离情况。结果表明:基因mp和de,cr和gl-2,cr和Tu,Tu和gl-2,Tu和ns间存在连锁遗传关系,它们的基因间距离分别为0.21,0.12,0.38,0.24,0.32cM(厘摩)。 Abstract:To study the linkage inheritance among gene mp for multi-pistillate flowering,de for determinate growth type,cr for crinkled leaf,gl-2 for glabrous leaf,ns for numerous spine,and Tu for tuberculate fruit in cucumber,the inbred NCG128,NCG157,WI2757 and NCG 042 were used as parents for 4 coombinations in the experiment.The traits of these genes were measured in field and the data was analyzed with a computer program SASGENE.The result indicated that the gene mp and de,cr and gl-2,cr and Tu,Tu and gl-2,Tu and ns had linkage relationship,and the distance between them was 0.21,0.12,0.38,0.24,0.32cM,respectively.     

Sesquiterpene lactones of diploid and tetraploid Ambrosia camphorata

Diploid and tetraploid specimens of Ambrosia camphorata have distinct sesquiterpene lactone patterns; however, no direct correlation between chemistry and morphological patterns is detectable.