The effect of soil salinity on the growth and competition among Helianthus paradoxus, H. annuus, and H. petiolaris was examined in a greenhouse experiment to determine the role competition might have in leading to the narrow endemism of H. paradoxus. Helianthus paradoxus (the Pecos sunflower or puzzle sunflower) is a threatened annual species that is federally listed and only found in a few are...

UNLABELLED • PREMISE OF THE STUDY Evolutionary changes in how flowering time responds to photoperiod cues have been instrumental in expanding the geographic range of agricultural production for many crop species. Locally adaptive natural variation in photoperiod response present in wild relatives of crop plants could be leveraged to further improve the present and future climatic ranges of cu...

The growth responses of a sunflower seedling (Helianthus annuus L.), subjected to repeated inversion, were characterized by time-lapse recording in conjunction with video image analysis. The investigation revealed a characteristic response pattern and established that the directional movement of the seedling is achieved by both inhibition and stimulation of growth in the normal growing regions....

the nutrient deficiency. The apparent narrow temperature range of maximum growth found in the old cultures of Chlorella and Anacystis also seem to be caused by such secondary effects. We have therefore prepared table I from the earliest clear pattern that developed. It should represent the optimum conditions for cultivating these algae. In figure 4 the development of a Chlorella pyrenoidosa and...

Much of our knowledge of speciation genetics stems from quantitative trait locus (QTL) studies. However, interpretations of the size and distribution of QTL underlying species differences are complicated by differences in the way QTL magnitudes are estimated. Also, many studies fail to exploit information about QTL directions or to compare inter- and intraspecific QTL variation. Here, we compre...

Many studies have shown that wind affects plant development, causing them to develop shorter and usually stronger stems. Many of these effects have been shown to be due to a response to mechanical flexing of the stem which is known as thigmomorphogenesis. However, it is not known how wind affects the hydraulic properties of stems, nor have the effects of air flow past leaves been examined in is...

The diploid hybrid species Helianthus deserticola inhabits the desert floor, an extreme environment relative to its parental species Helianthus annuus and Helianthus petiolaris. Adaptation to the desert floor may have occurred via selection acting on transgressive, or extreme, traits in early hybrids between the parental species. We explored this possibility through a field experiment in the hy...

A natural dye lawsone (2-hydroxy-1, 4-naphthoquinone) was isolated from dry leaves of Lawsonia inermis L., by extraction with clove oil, ethyl alcohol, water and its effectiveness as staining agent for angiospermic stem tissue was studied. Lawsonia revealed meta-chromatic property of staining. A 10%w/v crude extract of Lawsonia inermis L., leaves in ethyl alcohol and water were used for stainin...

Forecasting crop chemical characteristics based on soil properties is not only a possible way to spare supplementary sampling and testing, but also a potential method of instructing cultivation planning based on regional soil surveys. In this paper, taking the data of regional agricultural geological survey on Helianthus annuus sources in the western part of the Jilin province as an attempt, ra...

Leaf defenses are widely recognized as key adaptations and drivers of plant evolution. Across environmentally diverse habitats, the macroevolution of leaf defenses can be predicted by the univariate trade-off model, which predicts that defenses are functionally redundant and thus trade off, and the resource availability hypothesis, which predicts that defense investment is determined by inheren...