What the researchers go in for is to establish models between root architecture （RA） changes and nutrition, mold ideal root architecture of apple trees, improve the nutrient uptake efficiency, and further explore th...What the researchers go in for is to establish models between root architecture （RA） changes and nutrition, mold ideal root architecture of apple trees, improve the nutrient uptake efficiency, and further explore the functional mechanism of nutrient elements during the course of RA construction. The cultivation system of filter paper is utilized to research the effect of nutrient deficiency on the RA of Malus hupehensis （Pamp.） Rehd. There may be eight types of RA. In complete Hogland solution, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂. With the lack of P, K or Ca, the main type of RA is ＂lateral roots clustering in the upper region primary root＂, and the ＂lateral roots clustering in the upper and middle regions of primary root＂ types of RA decrease. But with shortage of P, the type of lateral roots clustering in the upper and lower regions of primary root increases, and the type of lateral roots clustering in the middle region of primary root decreases, with the types of RA diversified. Under the condition of K deficiency, the type of no lateral root increases and types of lateral roots clustering in the middle region of primary root decrease, and the percentage of such types as ＂no lateral root＂, ＂lateral roots clustering in the upper region of primary root＂, and ＂lateral roots clustering in the upper and middle regions of primary root＂ accounts for 97.9% in all, with the types of RA simplified. With lack of Fe, Mg or Zn, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂, but the type of lateral roots evenly-distributed on primary root increases. The main type of RA is ＂lateral roots evenlydistributed on primary root＂, under the condition of N deficiency, and the types of RA turn out to be diversified. There exists a close relation between nutrient deficiency and RA changes. Owing to various forms of nutrient deficiency, correspondingly different types of RA have been produced.展开更多
Malus hupehensis （Pamp.） Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4＋ ratios （100/0, 50/50, and 0/100, molar basis） at total nitrogen （N） concentration of 8 mmoL L-1...Malus hupehensis （Pamp.） Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4＋ ratios （100/0, 50/50, and 0/100, molar basis） at total nitrogen （N） concentration of 8 mmoL L-1 in a nutrient solution on M. hupehensis seedlings. Plant biomass, NO3- and NH4＋concentrafion, chlorophyll con- tent, respiratory rate, and cellular structure were investi- gated. M. hupehensis seedlings at the NO3-/NH4＋ ratio of 50/50 had the highest level of fresh weight, dry weight, shoot length, and chlorophyll （a, b, and a ＋ b） content, but the lowest respiration rate in the leavesand roots. In addition, thickness and numbers of palisade and spongy tissue cells of the leaves were greater with this treatment than with other treatments. At the NO3-/NH4＋ ratio of 100/0, the leaves and roots had higher NO3- concentration and lower NH4＋ concentration. However, the opposite trend occurred at the NO3-/NH4＋ ratio of 0/100. Chloro- phyll （a, b, and a ＋ b） content was lowest at the NO3-/NH4＋ ratio of 100/0 than at the other ratios. At the NO3-/ NH4＋ ratio of 0/100, oxygen （02） consumption increased in the leaves and roots, and irregular epidermis and cortex cells were observed in the root apical meristematic and mature region. Our results indicated that the NO3-INH4＋ ratio at 50/50 was suitable for growth of M. hupehensis seedling to achieve the highest biomass production and efficiency.展开更多
文摘What the researchers go in for is to establish models between root architecture （RA） changes and nutrition, mold ideal root architecture of apple trees, improve the nutrient uptake efficiency, and further explore the functional mechanism of nutrient elements during the course of RA construction. The cultivation system of filter paper is utilized to research the effect of nutrient deficiency on the RA of Malus hupehensis （Pamp.） Rehd. There may be eight types of RA. In complete Hogland solution, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂. With the lack of P, K or Ca, the main type of RA is ＂lateral roots clustering in the upper region primary root＂, and the ＂lateral roots clustering in the upper and middle regions of primary root＂ types of RA decrease. But with shortage of P, the type of lateral roots clustering in the upper and lower regions of primary root increases, and the type of lateral roots clustering in the middle region of primary root decreases, with the types of RA diversified. Under the condition of K deficiency, the type of no lateral root increases and types of lateral roots clustering in the middle region of primary root decrease, and the percentage of such types as ＂no lateral root＂, ＂lateral roots clustering in the upper region of primary root＂, and ＂lateral roots clustering in the upper and middle regions of primary root＂ accounts for 97.9% in all, with the types of RA simplified. With lack of Fe, Mg or Zn, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂, but the type of lateral roots evenly-distributed on primary root increases. The main type of RA is ＂lateral roots evenlydistributed on primary root＂, under the condition of N deficiency, and the types of RA turn out to be diversified. There exists a close relation between nutrient deficiency and RA changes. Owing to various forms of nutrient deficiency, correspondingly different types of RA have been produced.
基金supported by the Agricultural Comprehensive Development Project of Hebei Province(No.2012ACDPHP01)
文摘Malus hupehensis （Pamp.） Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4＋ ratios （100/0, 50/50, and 0/100, molar basis） at total nitrogen （N） concentration of 8 mmoL L-1 in a nutrient solution on M. hupehensis seedlings. Plant biomass, NO3- and NH4＋concentrafion, chlorophyll con- tent, respiratory rate, and cellular structure were investi- gated. M. hupehensis seedlings at the NO3-/NH4＋ ratio of 50/50 had the highest level of fresh weight, dry weight, shoot length, and chlorophyll （a, b, and a ＋ b） content, but the lowest respiration rate in the leavesand roots. In addition, thickness and numbers of palisade and spongy tissue cells of the leaves were greater with this treatment than with other treatments. At the NO3-/NH4＋ ratio of 100/0, the leaves and roots had higher NO3- concentration and lower NH4＋ concentration. However, the opposite trend occurred at the NO3-/NH4＋ ratio of 0/100. Chloro- phyll （a, b, and a ＋ b） content was lowest at the NO3-/NH4＋ ratio of 100/0 than at the other ratios. At the NO3-/ NH4＋ ratio of 0/100, oxygen （02） consumption increased in the leaves and roots, and irregular epidermis and cortex cells were observed in the root apical meristematic and mature region. Our results indicated that the NO3-INH4＋ ratio at 50/50 was suitable for growth of M. hupehensis seedling to achieve the highest biomass production and efficiency.
