Effect of the L-D_(1)alleles on leaf morphology,canopy structure and photosynthetic productivity in upland cotton(Gossypium hirsutum L.)

One of the most important objectives for breeders is to develop high-yield cultivars.The increase in crop yield has met with bottlenecks after the first green revolution,and more recent efforts have been focusing on achieving high photosynthetic efficiency traits in order to enhance the yield.Leaf shape is a significant agronomic trait of upland cotton that affects plant and canopy architecture,yield,and other production attributes.The major leaf shape types,including normal,sub-okra,okra,and super-okra,with varying levels of lobe severity,are controlled by a multiple allelic series of the D-genome locus L-D_(1).To analyze the effects of L-D_(1)alleles on leaf morphology,photosynthetic related traits and yield of cotton,two sets of near isogenic lines(NILs)with different alleles were constructed in Lumianyan 22(LMY22)and Lumianyan 28(LMY28)backgrounds.The analysis of morphological parameters and the results of virus-induced gene silencing(VIGS)showed that the regulation of leaf shape by L-D_(1)alleles was similar to a gene-dosage effect.Compared with the normal leaf,deeper lobes of the sub-okra leaf improved plant canopy structure by decreasing the leaf area index(LAI)and increasing the light transmittance rate(LTR),and the mid-range LAI of sub-okra leaf also guaranteed the accumulation of cotton biomass.Although the chlorophyll content(SPAD)of sub-okra leaf was lower than those of the other two leaf shapes,the net photosynthetic rate(Pn)of sub-okra leaf was higher than those of okra leaf and normal leaf at most stages.Thus,the improvements in canopy structure,as well as photosynthetic and physiological characteristics,contributed to optimizing the light environment,thereby increasing the total biomass and yield in the lines with a sub-okra leaf shape.Our results suggest that the sub-okra leaf may have practical application in cultivating varieties,and could enhance sustainable and profitable cotton production.

Effect of Spraying with GA₃on the Quality and Oil Content of Syrian Okra Seeds <i>Abelmoschus esculentus</i>(L.)

This study aimed to estimate the effect of spraying of okra plants, Abelmoschus esculentus (L.) with GA3 on the quality and oil content of the seeds. For this, the local okra variety was selected and used, which was growing widespread in the coastal region of Syria. This study was carried out in Al-Haffa area, Lattakia governorate, Syria (with 105 MSL elevation) for two seasons 2019-2020. The results showed that the effect of spraying with GA3 was more evident in the quality of the seeds as well as oil content at 75 ppm concentration with 68.7 g weight of 1000 seeds and 5.31% seed oil percentage. This study also showed that oil of local okra variety seed was rich in the essential fatty acids namely, linoleic, palmitic, oleic, stearic and linolenic, treatment with 75 ppm concentration of GA3 was more effective in the seed content of essential fatty acids with 42.30%, 32.55%, 9.20%, 6.73% and 5.72%, respectively. Finally, our results were indicated that treatment of okra plants at 75 ppm of GA3 enhanced the quality and oil content of seeds compared to the other concentrations.

陆地棉亚鸡脚叶种质耐干旱胁迫分析

为系统研究亚鸡脚叶种质的耐干旱能力,评价其在棉花遗传改良中的应用价值,本研究用聚乙二醇6000(PEG6000)模拟干旱胁迫,测定了干旱胁迫下亚鸡脚叶和常态叶材料幼苗形态、光合参数、叶绿素含量及叶绿素荧光最大光化学效率(Fv/Fm)、超氧化物歧化酶(SOD)、过氧化物酶(POD)过氧化氢酶(CAT)及抗坏血酸(APX)等抗氧化酶的活性及可溶性糖、脯氨酸、丙二醛(MDA)含量的差异。结果表明在15%PEG胁迫下,亚鸡脚叶和常态叶材料的差异最明显,亚鸡脚叶材料的蒸腾速率(Tr)、气孔导度(Gs)、净光合速率(Pn)、细胞间隙二氧化碳浓度(Ci)、叶绿素含量及Fv/Fm在胁迫及复水后均优于常态叶材料。亚鸡脚叶材料的SOD、POD、CAT及APX抗氧化酶活性及调节渗透物质(可溶性糖和脯氨酸)在胁迫过程中均高于常态叶材料。这说明无论是光合生理特性,还是干旱胁迫生理响应,亚鸡脚叶材料都优于常态叶材料,表现出更好的耐旱性,这为棉花耐旱新品种选育和遗传改良提供了材料支撑。