Rosette Phase Research Articles

Test results of the new herbicide Flex in soybean crops in Primorsky Territory

The biological and economic efficiency of the new herbicide Flex in post-emergence application to soybean crops of the variety Sphera was studied. The tests were carried out incompliance with the standard methods in the form of the plot experiment in 2017, 2018 on brown meadow podzolized soils in the south of the Far East. The preparation was tested in the consumption rates of 1.25 and 1.5 l/ha when the crop reached the development phase of two triple leaves as opposed to the standard herbicide Galaxy Top in the rate of 1.7 l/ha. It was found that Flex has a high herbicidal activity against all dicotyledonous annual and perennial species of weeds. Common ragweed (Ambrosia artemisiifolia L.) and Asian copperleaf (Acalypha australis L.) were highly sensitive to the preparation even in the minimum consumption rate. Especially strong toxic effect of Flex was produced on such weeds in the rosette phase as Asiatic dayflower (Commelina communis L.), lamb’s quarters (Chenopodium album L.), field milk thistle (Sonchus arvensis L.), creeping thistle (Cirsium setosum (Willd.) Bieb.) and common mugwort (Artemisia vulgaris L.). Consistent application of graminicide Fuzilade Forte in the rate of 1.5 l/ha after treatment of soybean crops with herbicide Flex contributed to an almost complete elimination of annual grass weeds. The high biological efficiency of the experimental preparation contributed to a significant increase in crop yield. In 2018, when it was applied in the minimum rate of 1.25 l/ha, the yield achieved was 0.94 t/ha, exceeding the control value by 3.3 times. The highest yield increase of soybean seeds (1.12 t/ha on average for 2 years) was obtained with the use of herbicide Flex in the maximum consumption rate of 1.5 l/ha. Application of herbicide Flex to soybean crops in the rates of 1.25 and 1.5 l/ha alongside with the preparation Trend 90 in the rate of 0.2 l/ha proved to be highly effective in eliminating annual and perennial dicotyledonous weeds (in early stages of development) from soybean crops.

Effect of the cutting date on blooming and fruit-bearing of Ostericum palustre Beesser

In fresh moist meadows, double-cut, located in the Bydgoszcz Canal Valley, you can find <i>Ostericum palustre</i>, a species of priority importance, which requires protection in the form of designation of Natura 2000 sites. The aim of the present research was to define the effect of the cutting date on blooming and fruit-bearing of <i>O. palustre</i> in meadows covered by the PO1b agro-environmental programme. Phenological observations included three populations of <i>O. palustre</i>. The first one occurs in a traditionally used meadow, not covered by the agro-environmental programme (2) where the date of the first cut falls in mid June. The second one is located in a meadow covered by the agro-environmental programme (1) where the first cutting date is possible from July 1, and the third population located in a natural meadow is not agriculturally used (0). The present research showed that individuals of <i>O. palustre</i> in the traditionally used meadows (2), prior to the first cut, reach the leaf rosette phase, while individuals which occur in the meadow covered by the agro-environmental programme (1), prior to the first cut, reach the generative tiller phase. Full bloom of <i>O. palustre</i> in the traditionally used meadows occurs after July 20, while individuals of <i>O. palustre</i> in the agro-environmental programme reach that phase only at the beginning of August. At the same time, about August 6, the first inflorescence in 70% of individuals in the agriculturally unused meadow (0) has ripe fruit, and in mid August all fruits are ripe. In mid August 70% of individuals in the meadow used for traditional cutting have ripe fruits of the first inflorescence, and right before the second cut, on August 27, almost 90% of fruits were ripe. Most <i>O. palustre</i> individuals in the meadows covered by the agro-environmental programme do not finish blooming of the first inflorescence before mid August. By the end of August, about 60% of individuals reach the phase of young fruits. The first ripe fruits occur as late as September 12. About September 20 most fruits are ripe. To sum up, delayed PO1b agro-environmental programme meadow cutting, after July 1, does not facilitate the production of ripe fruit in <i>O. palustre</i> individuals.

Response of hoary alyssum (Berteroa incana L.) to UV-B radiation

This greenhouse experiment evaluated the response of hoary alyssum plants, up to the rosette phase, to different levels of UV-B radiation. The experiment was carried out in the chambers, equipped with UV-B lamps, emitting biologically effective UV-B radiation of 0 (control), 4, 6 or 8 kJ. As a result, specific traits of the plants such as: leaf number, lamina length, leaf area, specific leaf weight, relative chlorophyll content and shoot biomass were unaffected by any of the UV-B treatments. Significant reductions in the share of large leaves, leaf stalk length and root biomass were noted for plants growing under 8 kJ UV-B<sub>BE</sub>.

Content of Essential Oil and Valerenic Acids in Valerian (Valeriana offcinalis L.) Roots at the Selected Developmental Phases

The content of essential oil and valerenic acids and the yield of roots were analyzed in valerian cultivar ‘Polka’ and strain no. 4 during the nine following phases: the beginning of vegetation, spring rosette, pedicel development, the beginning of flowering, full bloom, seed harvest, three weeks after the seed harvest, fall rosette, and after the first frost. The yield of valerian roots was different at the investigated phases and in years of cultivation, while tested genotypes produced similar root yields. The highest contents of essential oil and valerenic acids were obtained at different phases by the tested genotypes: strain no. 4 in full bloom (1.3% and 0.266%, respectively) and cultivar ‘Polka’ three weeks after seed harvest (1.25%) and during seed harvest (0.218%). The lowest contents of the investigated substances were detected at the beginning of growth and after the first frost in both genotypes. The obtained results revealed significant differences in essential oil and valerenic acids content, which depend on genotype, plant age, harvest time and the year of cultivation. The results suggest that higher amounts of valerenic acids could be obtained in the second year of cultivation over the period from full bloom (0.278%) to fall rosette phase (0.316%).

A quantitative study of lateral branching in petunia.

The monopodial shoot axis of petunia (Petunia hybrida Vilm) has two different patterns of branch development. Basal lateral branching develops acropetally and is limited to a discrete number of nodes that correlate with the late rosette phase of growth (Zone II). Two zones of suppressed buds immediately precede and follow this zone of branching. Apical branching occurs in response to flowering, develops in a basipetal direction, and is restricted to the distal-most nodes on the monopodial axis. When grown under a short-day regime, an extension to the basal branching zone occurs, and growth of the main shoot axis is retarded. The sym1 mutant has an overall decrease in basal lateral branching compared with wild type whereas the three dad mutants have increased basal branching. The dad1-1 and dad2-1 mutants have no initial zone of suppressed branching whereas the dad3 mutant has a similar Zone II to wild type, but with a greater potential to form branches within this zone. The dad1-1 mutant exhibits delayed flowering, but the dad1-1 sym1 double mutant flowers at a similar node number to wild-type and branching is similar to dad1-1 indicating that these two aspects of the mutant dad1-1 phenotype are independent.

Morphogenetic variation for artemisinin and volatile oil in Artemisia annua

Seeds of Artemisia annua cv. Jeevanraksha were sown in the nursery in the middle of December in 1997, 1998 and 1999. About 1-month old seedlings were transplanted in the field having sandy loam soil in the subtropical agroclimate of Lucknow, India. The plant tops were sampled fortnightly for leaves during vegetative phase and for leaves and capitula during post-flowering stages for the estimation of artemisinin content. The A. annua plants continued to grow logarithmically in height from the end of rosette phase at about 9 weeks to the pre-flowering stage at about 44 weeks age and attained a height of 3.4 m. The artemisinin content of the leaves was observed to be high from 0.8 to 1.0% in May and 0.8 to 1.3% through late July to late September. Subsequently, plants entered the reproductive phase. While in the vegetative phase, 90% of artemisinin was in the leaves, in the mature plants, about 30% of the artemisinin was in the leaves and 40% was in capitula. In the vegetative stage plants the younger leaves born on the tops of secondary and higher order branches were richer in the artemisinin than the older leaves. The tops of A. annua plants in their vegetative growth phase possessed low levels of essential oil at about 0.2% as compared to 1.2% of essential oil in the full blooming stage plants. The extraction of artemisinin from leaves is more economic than from the mixture of leaves and capitula on account of higher levels of lipids in the extract of the latter. Since A. annua plants grew logarithmically all through vegetative phase from March to late September and artemisinin content in the leaves was high in May and from late July to late September, it is suggested that under the subtropical agroclimates, A. annua crops may be harvested more than once. The ratooning is expected to reduce losses in artemisinin yield resulting from senescence caused dropping of old leaves and favour preponderance of young leaves found richer in artemisinin content.

FREE POLYAMINES CONTENT IN BRASSICA RAPA L. DURING GROWTHSTAGES

The content of free polyamines (putrescine, spermidine and spermine) was studied in the plant and organs of Brassica rapa during growth-stages. The putrescine level reduced in the stem and roots after the seedling phase, whereas in the leaves and shoot this occurred after the rosette phase. In the plant the concentration is at maximum during the rosette phase and minimum during the seed stage. The spermidine and spermine showed similar developments.

カスミソウ（Ｇｙｐｓｏｐｈｉｌａ ｅｌｅｇａｎｓ Ｂｉｅｂ．）の抽だいと開花に及ぼす播種期，日長および栽培温度の影響

1月から5月の間に播種したカスミソウは, 100%の株が播種後3ヵ月以内に抽だいした. 播種時期が8月以降になると抽だい率は急速に低下し, 9月から10月に播種した株は冬季ロゼット状態の生育を続け, 2月下旬に抽だいした. 到花日数は1月から6月まで播種時期が遅くなるにしたがって減少し, 9月に播種した場合に最も長かった.8時間と10時間日長では播種時期に関係なくロゼット状態の生育を続け, 日長が長いほど抽だい率が高かった. 長日の抽だい, 開花促進効果は日長が24時間まで長いほど連続的に増大し, 24時間日長では播種後5~8週間の短期間に開花して生育を終了した.また夏以降ロゼット状態にある株は, 長日処理によって抽だいと開花が促進され, その効果は16時間日長に比べて24時間日長の方が著しく高かった.冬季, 温度と日長を変えて栽培すると, 抽だい, 開花は高温, 長日条件で著しく促進された. 自然日長では短日期には抽だいせず, 2月下旬から抽だいして4月下旬に開花した. 最低気温15°Cでは切り花長が短く, 加温の温度は10°C以下が適した. カスミソウは10時間と12時間の間に抽だい, 開花のための限界日長をもつ絶対的長日植物であり, ロゼット化および抽だい, 開花は主として日長に規定され, 温度の影響は小さかった.

Growth and reproduction of Arabidopsis thaliana in relation to storage of starch and nitrate in the wild‐type and in starch‐deficient and nitrate‐uptake‐deficient mutants

ABSTRACTWe have investigated the interactions between resource assimilation and storage in rosette leaves, and their impact on the growth and reproduction of the annual species Arabidopsis thaliana. The resource balance was experimentally perturbed by changing (i) the external nutrition, by varying the nitrogen supply; (ii) the assimilation and reallocation of resources from rosette leaves to reproductive organs, by cutting or covering rosette leaves at the time of early flower bud formation, and (iii) the internal carbon and nitrogen balance of the plants, by using isogenic mutants either lacking starch formation (PGM mutant) or with reduced nitrate uptake (NU mutant).When plants were grown on high nitrogen, they had higher concentrations of carbohydrates and nitrate in their leaves during the rosette phase than during flowering. However, these storage pools did not significantly contribute to the bulk flow of resources to seeds. The pool size of stored resources in rosette leaves at the onset of seed filling was very low compared to the total amount of carbon and nitrogen needed for seed formation. Instead, the rosette leaves had an important function in the continued assimilation of resources during seed ripening, as shown by the low seed yield of plants whose leaves were covered or cut off. When a key resource became limiting, such as nitrogen in the NU mutants and in plants grown on a low nitrogen supply, stored resources in the rosette leaves (e.g. nitrogen) were remobilized, and made a larger contribution to seed biomass. A change in nutrition resulted in a complete reversal of the plant response: plants shifted from high to low nutrition exhibited a seed yield similar to that of plants grown continuously on a low nitrogen supply, and vice versa. This demonstrates that resource assimilation during the reproductive phase determines seed production.The PGM mutant had a reduced growth rate and a smaller biomass during the rosette phase as a result of changes in respiration caused by a high turnover of soluble sugars (Caspar et al. 1986; W. Schulze et al. 1991). During flowering, however, the vegetative growth rate in the PGM mutant increased, and exceeded that of the wild‐type. By the end of the flowering stage, the biomass of the PGM mutant did not differ from that of the wild‐type. However, in contrast to the wild‐type, the PGM mutant maintained a high vegetative growth rate during seed formation, but had a low rate of seed production. These differences in allocation in the PGM mutant result in a significantly lower seed yield in the starchless mutants. This indicates that starch formation is not only an important factor during growth in the rosette phase, but is also important for whole plant allocation during seed formation. The NU mutant resembled the wild‐type grown on a low nitrogen supply, except that it unexpectedly showed symptoms of carbohydrate shortage as well as nitrogen deficiency.In all genotypes and treatments, there was a striking correlation between the concentrations of nitrate and organic nitrogen and shoot growth on the one hand, and sucrose concentration and root growth on the other. In addition, nitrate reductase activity (NRA) was correlated with the total carbohydrate concentration: low carbohydrate levels in starchless mutants led to low NRA even at high nitrate supply. Thus the concentrations of stored carbohydrates and nitrate are directly or indirectly involved in regulating allocation.

AN ECOPHYSIOLOGICAL STUDY IN THE FIELD LAYER OF ASH COPPICE III INFLUENCE OF DIMINISHING LIGHT INTENSITY DURING GROWTH ON GEUM URBANUM AND CIRSIUM PALUSTRE

SUMMARY The adaptability of Cirsium palustre, a shade avoiding species, and Geum urbanum, a species avoiding exposed conditions in the ash coppice cycle, to a change from a high to a low light intensity was studied, in order to simulate the changes taking place in the light climate in a deciduous woodland in spring. Both the vegetative rosette phase and the generative phase were considered. In the rosette phase a rapid adaptation to the low light intensity took place in both species in a similar way. In the generative phase Geum adapted much better after the plants had been transferred from a high to a low light intensity. The dry weight increase of Cirsium ceased after the transfer, whereas Geum continued to grow. The leaf area ratio was much higher after the transfer, giving better assimilation in limiting light conditions. Cirsium when continuously grown in a low light intensity also had a high leaf area ratio, but the stems were too weak to support themselves, in contrast with Geum. So in the vegetative phase both species can be considered shade tolerant, but Cirsium palustre is not shade tolerant in the generative phase.

Inheritance of Field Reaction to Soil‐Borne Wheat Mosaic Virus1

A five‐parent incomplete winter wheat diallel cross was studied for inheritance of field reaction to Soil‐ Born Wheat Mosaic Virus (SBWMV).Resistance was found to be monogenic dominant over both susceptibility to mosaic and to mosaic‐rosette, and susceptibility to mosaic was, likewise, monogenic dominant over mosaic‐rosette susceptibility. The results were interpreted on the basis of the operation of a multiple allelic series consisting of three alleles, viz, (1) Rmr which governs resistance to mosaic and mosaic‐rosette, (2) γm which is recessive to Rmr and conditions susceptibility to mosaic but is resistant to the rosette phase and (3) γmr which is recessive to both Rmr and γm and is responsible for mosaic‐rosette susceptibility.