In many seeds, the micropyle of the ovule also persists as a small opening in the seed coat. The embryo , variously located in the seed, may be very small as in buttercups or may fill the seed almost completely as in roses and plants of the mustard family.
It consists of a root part, or radicle, a prospective shoot plumule or epicotyl , one or more cotyledons one or two in flowering plants, several in Pinus and other gymnosperms , and a hypocotyl, which is a region that connects radicle and plumule. A classification of seeds can be based on size and position of the embryo and on the proportion of embryo to storage tissue; the possession of either one or two cotyledons is considered crucial in recognizing two main groups of flowering plants, the monocotyledons and the eudicotyledons.
Seedlings, arising from embryos in the process of germination , are classified as epigeal cotyledons aboveground, usually green and capable of photosynthesis and hypogeal cotyledons belowground. It is difficult to evaluate sesame because it has a great ability to compensate for injury, stunting, and stand reduction. In many of the herbicide studies where sesame injury is severe following preemergence PRE and postemergence POST herbicide treatments, sesame yields are acceptable because the plants can compensate for open space by additional branches with capsules.
However, branching can only compensate for gaps of less than 30 cm. Wider gaps not only lead to lower yields, but also let light through the canopy to encourage late-season weed emergence and growth. The majority of sesame in the world is grown manually — manual planting, manual control of weeds, and manual harvest [ 23 , 24 ]. In countries where there is abundant, cheap manual labor, this methodology will persist. However, in countries such as the USA, the price of sesame will not allow for much manual labor.
Planting, cultivating, and harvesting are done mechanically; however, in some cases, manual labor is still required for weed control. The purpose of weed research over the past 23 years conducted by the authors has been to control weeds with the use of herbicides.
Preplant-incorporated herbicides such as trifluralin, pendimethalin, and ethalfluralin can provide good weed control, but a stand of sesame can be destroyed if precipitation moves the soil particles containing the herbicide into the root zone at an early growth stage [ 25 , 26 ]. There are numerous studies that have shown that alachlor can be and is used in most of the sesame growing countries around the world [ 31 , 32 ].
The POST graminicides, fluazifop-p-butyl and sethoxydim, provide good grass control at all stages of growth, while clethodim may cause injury when sprayed during the reproductive phase [ 29 ]. As for broadleaf weeds, diuron and fluometuron applied POST provide reasonable control but there is risk of injury to sesame [ 29 ].
With the exception of glyphosate, which will kill sesame when applied POST, most of these herbicides will moderately to severely damage sesame but will not kill it [ 7 ]. In the USA, the use of glyphosate or glufosinate-ammonium tolerant hybrids or varieties in most of the major field crops such as corn Zea mays L. New cotton and soybean transgenic varieties with traits conferring resistance to the synthetic auxin herbicides, 2,4-D and dicamba 2,4-DR and DR, respectively have been developed [ 40 - 42 ] and are expected to be quickly adopted by growers who will use these traits to control glyphosate- and glufosinate-ammonium-resistant weed species [ 43 - 46 ].
This type of methodology cannot be used for weed control in sesame because, similar to wheat Triticum aestivum L. There is a second issue with the universal use of POST herbicides. When the plants reach a certain height or size, the POST herbicides do not reach below the canopy or on the ground in the seed zone.
In the past, many US growers used directed sprays in traditional cropping systems, but much of that equipment has been idle for many years. However, because of weed resistance issues in many areas of the country [ 33 - 35 ], there has been a resurgence in the use of this type of equipment that might be utilized in sesame production.
The directed spray equipment covers fewer acres per hour compared to the newer over-the-top sprayers and thus has not been the preferred method of weed control; however, growers have begun to use directed sprayers on sesame.
Label the Diagram. Complete the Table. What Goes IN. Light Dependent. Light Independent. Calvin Cycle. Photosynthesis Worksheets and Printables enjoy reading, tracing, and coloring helpful diagrams as they learn about how plants use the sun to create energy. Introduction Sesame seed oil is a highly esteemed edible oil that is either consumed as edible oil, or used for pharmaceutical and health purposes.
Sesame Sesamum indicum L is a very drought-tolerant plant, partly due to its extensive root system and also due to its high temperature tolerance.
It is grown in many regions of the world [ 1 ]. Upon ripening, the sesame capsule splits open and releases the seed, therefore usually the plants are collected before ripening and stored vertically to prevent seed loss when the capsules split. Because of this shattering characteristic accompanied by its indeterminate growth, sesame is cultivated primarily on small plots that are harvested by hand. Due to this laborious harvesting sesame seeds are rarely produced in highly industrialized western countries.
The discovery of an in-dehiscent non-shattering mutant by Langham in allowed breeding of high yielding, shatter-resistant varieties being used in industrialized countries like the USA [ 1 ]. In many countries local native products are favored to foreign ones, as has been investigated in Korea with respect to beef [ 2 ]. Thus, methods to control the declared origin of food products to protect regional brands and enhance consumer confidence are increasingly gaining importance.
Since sesame seed oil of declared geographic origin is more highly valued by consumers than sesame oil without geographic designation, there is the danger of consumer deception by labeling or admixing cheaper sesame oil of a different geographic origin than indicated on the label to increase profit. Consequently methods are needed to control the declared origin of a produce and to identify the origin of sesame oil and seeds. There are already numerous publications on the authenticity of sesame oil with respect to adulteration [ 3 — 9 ], however, there are almost no studies on the geographic origin or isotopic data of sesame oil available.
Divalent cations and heat were used to fragment the purified poly- A mRNA before library construction. Light Independent. Mahgoub et al. Plot size was five rows 76 cm apart by 9. Materials and methods 2. Light reactions.
For sesame, so far only general molecular diversity analyses have been performed in collections from different countries such as Sudan [ 29 ], India [ 30 ], Turkey [ 31 ] or Vietnam and Cambodia [ 32 ] in order to determine genetic relations between germ plasm lines, or to estimate genetic diversity present [ 33 — 34 ]. Herbicides and spraying information Herbicides and doses included in the study are shown in Table 1.
Figures Abstract Waterlogging is a common adverse environmental condition that limits plant growth. Sesame self-defoliates while it is maturing and drying down, thus introducing another period of vulnerability to weeds once the sunlight is again able to reach the soil surface. For the stable carbon and hydrogen isotope data a positive correlation between both isotope parameters was observed, indicating a dominant combined influence of climate and water availability. Sesame Sesamum indicum is considered a drought-tolerant oil crop but is typically susceptible to harmful effects from waterlogging. Photosynthesis Worksheets and Printables enjoy reading, tracing, and coloring helpful diagrams as they learn about how plants use the sun to create energy.
Soil type at Uvalde was a Winterhaven silty clay loam fine-silty, carbonatic, hyperthermic Fluventic Ustochrepts with less than 1. To understand the effects of abiotic stress in an effort to maintain a stable food supply, a number of studies have investigated the responses of model plants and crops to stresses [ 7 ]. In some cases, the vines of these weeds start climbing the sesame plant from the ground line and are not covered by the glyphosate application.
The majority of sesame in the world is grown manually — manual planting, manual control of weeds, and manual harvest [ 23 , 24 ]. GO term and metabolic pathway enrichment analyses were performed according to Wang et al. The events just described constitute what is called the double-fertilization process, one of the characteristic features of all flowering plants. A nontreated control was included for comparison. The diagram given in this BiologyWise article is a small pictorial elaboration of the process of photosynthesis that will prove helpful for kids and teenagers to understand this vital process of the plant kingdom. This results in a reduced discrimination of the heavy C-isotopes, as compared to a situation without CO2 limitation where heavy isotopes are less likely to be incorporated in newly synthetized carbohydrates [ 22 ].
In mechanical harvest, weeds are cut at the same time as the sesame. Differences in isotopic patterns of samples from different origins therefore have the potential for the verification or control of geographic authenticity.
The critical period of weed control is the time interval where control is essential to avoid a yield loss and is the interval between the length of weed competition tolerated and the weed-free requirement [ 17 ].
This low yield may be attributed to several reasons, but waterlogging is a primary factor that has a severe effect in countries such as China and Korea due to changing climate. In some cases, the vines of these weeds start climbing the sesame plant from the ground line and are not covered by the glyphosate application. Kropff and Spitters [ 9 ] reported that the major factor influencing sesame yield loss in a competitive situation between the crop and weed is the ratio between the relative leaf area of the weed and the crop at the time of canopy closure. The second process explains the depletion in heavy isotopes in precipitation in inland areas compared to regions close to the sea due to the preferred out-raining of heavy isotopes, which passively enriches the remaining water vapor moving further inland in light isotopes. The pollen tube has three haploid nuclei, one of them, the so-called vegetative , or tube, nucleus seems to direct the operations of the growing structure. Fields were selected that had low weed populations so any plant response could be attributed to the herbicide treatment and not weed competition.